GENERAL PRACTITIONER EXAM
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Question 1 of 100
1. Question
1 pointsA 29 year old female being treated for depression begins to exhibit muscle rigidity. Her posture becomes stooped, and a shuffling gait is noted when she walks. The patient´s facial expression becomes “mask like” and she begins to drool. This woman would be taking which of the following tricyclic antidepressants?
Correct
Incorrect
Explanation:
Although all of the drugs are used in the treatment of depression, only amoxapine is associated with complications that mimic Parkinson´s disease. These symptoms include muscle rigidity a stooped posture, a shuffling gait, and a “mask like” expression associated with drooling. -
Question 2 of 100
2. Question
1 pointsDrug that is associated with permanent discoloration of the teeth when given to children is
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Explanation:
Tetracyclines administered to the mother during the second half of pregnancy or to children up to about age eight cause permanent dental discoloration. The other agents have not been associated with such discoloration. -
Question 3 of 100
3. Question
1 pointsThe diuretic that works at the proximal convoluted tubule is
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Incorrect
Explanation:
Acetozolamide works at the proximal tubule and prevents HCO3- reabsorption, which can cause a metabolic acidosis (furosemide and thiazides may cause a metabolic alkalosis). Furosemide works at the ascending loop of Henle and may be ototoxic (the other choices are not commonly ototoxic). Thiazide diuretics work at the distal convoluted tubule and can cause hyperuricemia. Spironolactone is a K+ sparing diuretic that works at the distal tubule and collecting duct (the other diuretics are more likely to cause hypokalemia). -
Question 4 of 100
4. Question
1 pointsA 59 year old alcoholic male with COPD is receiving theophylline. Serum levels of theophylline are persistently lower than expected for the prescribed dose the patient is receiving. His wife has not missed any of the doses. What is the most likely explanation for these laboratory findings?
Correct
Incorrect
Explanation:
The patient is an alcoholic, and alcohol normally enhances the cytochrome P450 system in the smooth endoplasmic reticulum (SER) of the liver. This system is responsible for the metabolism of drugs hence the low theophylline levels are most likely due to enhanced liver metabolism. Specifically, theophylline is primarily metabolized by CYP1A2 isoenzmes, with a secondary pathway by CYP3A4; therefore, agents or pathologic processes altering this pathway will affect its metabolism. The hepatocyte SER undergoes hyperplasia as a response to alcohol ingestion and synthesizes the enzyme gamma glutamyl transferase (GGT). An elevation of GGT In this particular patient would help confirm the likelihood of increased hepatic drug metabolism as the cause of low drug levels. Cirrhosis of the liver would likely increase the serum levels of theophylline because of poor metabolism of the drug. Decreased absorption of the drug in the gastrointestinal tract is a possible choice. However, the history of excess alcohol intake and lack of a history of malabsorption suggest increased hepatic metabolism. Increased clearance of theophylline in the urine implies an increase in the glomerular filtration rate, which would not be expected in this patient. Since the patent´s wife is administering the medication, noncompliance is highly unlikely. However, in most circumstances, the lack of an expected response to a medication is due to patient noncompliance until proven otherwise. -
Question 5 of 100
5. Question
1 pointsA 68 year old woman feels “lightheaded.” ECG is non-diagnostic, but 24-hour monitoring reveals paroxysmal supraventricular tachycardia. Agent that is most likely responsible for causing this condition in this patient is
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Explanation:
Digoxin is a cardiac glycoside that can cause paroxysmal supraventricular tachycardia (PSVT) when toxic levels are reached. Digoxin can be given for PSVT but too much digoxin can result in PSVT. When this occurs, it is commonly associated with AV block and in patients without structural heart disease. The heart rate most commonly ranges from 160 to 220beats/min. When digoxin is implicated as the causative agent, initial treatment consists of discontinuing the medication, possible use of digoxin-F(ab) fragments, correcting any underlying electrolyte abnormalities (e.g., potassium), and initially performing cardioversion, which will terminate more than 90% of episodes. Atropine blocks cardiac muscarinic receptors, thereby increasing conduction through the AV node.
Adenosine is generally indicated as the first agent of choice for the treatment of PSVT. Diltiazem is indicated for PSVT patients unresponsive to adenosine. Esmolol is indicated for PSVT patient unresponsive to adenosine. Quinidine acts centrally to decrease vagal tone, thereby increasing AV conduction. This agent can be used as a preventative agent for supraventricular tachycardias; however, because other less toxic and more efficacious agents are available, it is not commonly used for this condition. -
Question 6 of 100
6. Question
1 pointsA 56 year old is diagnosed with type 2 diabetes. A drug is prescribed that regulates the release of adipokines (resistin and adiponectin). The mechanism of action by which this medication acts can be described as which of the following?
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Explanation:
Thiazolidinediones, such as pioglitazone, are antidiabetic agents that increase insulin sensitivity through a variety of mechanisms, resulting in decreased hepatic gluconeogenesis and increased insulin dependent muscle glucose uptake. Specifically, drugs of this class sensitize peripheral tissues to insulin because they regulate the release of the adipokines (resistin and adiponectin) from adipocytes. Adiponectin secretion is stimulated, which sensitizes tissues to the effects of insulin, and resistin secretion is inhibited which reduces insulin resistance. The net result is an enhancement of glucose uptake by the muscle cells. The pharmacologic effects of thiazolidinediones also include increased glucose transporter expression (GLUT1 and GLUT4), decreased freefall acid levels, decreased hepatic glucose output and increased differentiation of pre-adipocytes into adipocytes. Alpha-glycosidase inhibitorssuch as acarbose, act by decreasing carbohydrate absorption from the intestinal tract which in turn lowers postprandial glucose levels. Chlorpropamide, glyburide, and tolbutamide are sulfonylurea oral hypoglycemic agents that stimulate the secretion of insulin from the pancreatic beta cells. -
Question 7 of 100
7. Question
1 pointsAfter cholecystectomy a 46 year old female has develops severe right upper quadrant pain. Investigation reveals elevated bilirubin with severely elevated AST and ALT. Ultrasound shows an enlarged liver with no anomalies in the biliary tree. Her hepatic failure is best explained by which one of the following?
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Incorrect
Explanation:
Halothane was the first halogenated volatile anesthetic produced; and shortly after its introduction the first cases of “halothane hepatitis” were reported. After exposure to this inhaled anesthetic agent, patients may experience hepatitis with focal to massive hepatic necrosis. Mechanisms that have been proposed for halothane associated hepatitis include the formation of hepatotoxic metabolic intermediates and immune hypersensitivity. In this case, the elevated bilirubin results from the mildly obstructed biliary tree. Obstruction results from disruption of hepatic architecture secondary to swelling. The elevated AST and ALT reveal that hepatocellular death has occurred, since hepatocytes release these enzymes as they lyse. A dislodged cystic duct staple would not produce hepatic failure and necrosis. Bile leaking into the peritoneal cavity would produce severe peritoneal irritation and peritonitis. ALT and AST would not be significantly elevated, as no hepatocellular death is occurring. A retained common duct stone presents as continued episodes of colicky right upper quadrant pain and jaundice. Endoscopic retrograde cholangiopancreatography (ERCP) will provide diagnostic imaging as well as the therapeutic opportunity to manually remove the stone. Postoperative aminoglycoside antibiotics do not cause massive hepatic necrosis. They may, however, produce nephrotoxicity and ototoxicity. Adequate hydration may decrease the incidence of nephrotoxicity. Postoperative ketorolac does not produce massive hepatic necrosis. Metabolized in the kidney, this nonsteroidal anti-inflammatory agent produces the same toxicities as other drugs in this class: gastric ulcers and renal failure. Renal failure is precipitated by NSAIDs because they inhibit the production of prostaglandins in the afferent arterioles; prostaglandins normally maintain vasodilation and GFR. -
Question 8 of 100
8. Question
1 pointsA 36 year old man is undergoing treatment to prevent liver transplant rejection. Along with corticosteroid therapy he is also given a drug that reduces the activation of cytotoxic T lymphocytes by inhibiting is interleukin IL-2 production. Which IL-2 inhibitor would be indicated in this patient?
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Explanation:
Tacrolimus is a soil fungus derived macrolide that inhibits calcineurin mediated transcription of IL-2. Tacrolimus binds to an immunophilin called FR binding protein 12 (FKBP12), and produces immunosuppression by a mechanism that involves inhibition of the first phase of T-cell activation. Azathioprine is converted to 6-mercaptopurine, which inhibits DNA synthesis and subsequent cell proliferation. Cyclophosphamide inhibits cell proliferation by alkylating DNA. 6-Mercaptopurine is a purine antimetabolite that acts during S-phase and is bio-activated by HGPRT. Sirolimus is approved for use in renal transplantation and inhibits T cell proliferation by binding a specific serine-threonine kinase (mTOR) that is necessary for cell cycle. -
Question 9 of 100
9. Question
1 pointsA 65 year old female has been taking salicylates and other NSAIDs for the past 18 months without adequate relief of her arthritis symptoms. Her physician decides to start methotrexate therapy. Over the next 7 weeks she receives prednisone as a form of “bridging therapy” to help prevent pain and inflammation while waiting for the pharmacologic benefits of methotrexate to begin. She is likely to experience which one of the following secondary to her glucocorticoid therapy?
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Incorrect
Explanation:
. Methotrexate is a type of disease-modifying antirheumatic drug (DMARD). DMARDs are a varied group of drugs, including methotrexate, azathioprine, penicillamine, hydroxychloroquine and chloroquine, organic gold compounds, and sulfasalazine, that are thought to slow the progression of rheumatoid arthritis by modifying the disease itself. However, these drugs can take several weeks to several months to produce therapeutic effects. In rheumatoid arthritis, prednisone is used when persistent synovitis is seen in multiple joints despite sufficient; dosage of NSAIDs. It is also used for “bridge” therapy when DMARD therapy with methotrexate is first initiated. Because it takes a long time for the therapeutic effect of DMARDs to become evident, agents like prednisone needed to “bridge the gap” between NSAID therapy and DMARD therapy. The major disadvantage of using glucocorticoids for an extended period of time is the severe side effect profile. For example, long-term use of prednisone is associated with hypocalcemia, fluid retention (not dehydration), hypokalemia (not hyperkalemia), hyperglycemia (not hypoglycemia), and hypernatremia (not hyponatremia). Other adverse reactions include adrenal suppression, muscle weakness and atrophy, gastritis, nausea, vomiting, Cushingoid state (moon face, buffalo hump, central obesity), immunosuppression, hypertension, psychosis, osteoporosis, glaucoma, and posterior subcapsular cataracts. -
Question 10 of 100
10. Question
1 pointsA 16 year old presents after suffering a generalized tonic-clonic seizure. He is restless and irritable and has nausea and headache. He had been experimenting with cocaine earlier that day. Examination reveals a heart rate of 130/min and a blood pressure of 150/95 mm Hg. What is the mechanism for the cocaine induced hypertension?
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Explanation:
Cocaine is a stimulant that causes hypertension and tachycardia by blocking norepinephrine uptake. This leads to an accumulation of norepinephrine in the synapse, causing greater stimulation of postsynaptic receptors. The receptors that mediate the systemic vasoconstriction are alpha-1 adrenergic receptors, and the receptors that mediate the increases in heart rate and inotropic state are beta 1 adrenergic receptors. Symptoms of cocaine toxicity include CNS stimulation, anxiety, tachycardia, hypertension diaphoresis, mydriasis, and psychosis, as well as hyperactivity of the muscles, leading to metabolic acidosis and rhabdomyolysis. Direct stimulation of alpha-1 receptors would increase blood pressure, but this is not cocaine´s mechanism of action.
Direct stimulation of beta-1 receptors could increase blood pressure by increasing the inotropic state, but this is not cocaine´s mechanism of action. Direct stimulation of beta-2 receptors would cause vasodilation in the skeletal muscle vasculature, leading to a decrease in blood pressure. Induction of norepinephrine release would increase blood pressure, but this is the mechanism of action of amphetamine, not cocaine. -
Question 11 of 100
11. Question
1 pointsA pregnant lady aged 38 years with a past medical history significant for chronic hypertension presents with a blood pressure of 158/105mm Hg. Which antihypertensive agent would be most suitable for initial therapy in this patient?
Correct
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Explanation:
Pregnant women with chronic hypertension “require” antihypertensive therapy when the diastolic pressure is greater than 100 mm Hg; however some clinicians may decide to treat patients with diastolic blood pressures less than 100 mm Hg. For the initiation of therapy, methyldopa is still considered to be the agent of choice. Methyldopa is converted intraneuronally to α-methylnorepinephrine, an alpha 2 adrenergic agonist, which is subsequently released. Release of alpha methylnorepinephrine in the medulla leads to a decrease in sympathetic outflow thus lowering blood pressure. Methyldopa has been safely used in the treatment of hypertension during pregnancy; this agent is not associated with the development of teratogenic or other fetal abnormalities. Diuretics, such as bumetanide and hydrochlorothiazide, are often avoided because these agents can produce hypovolemia, leading to reduced uterine blood flow. Although these agents can be used during pregnancy, methyldopa and hydralazine are the drugs of choice for hypertension during pregnancy. Fosinopril is an angiotensin converting enzyme (ACE) inhibitor that should not be administered to pregnant women, especially in the second or third trimesters. These agents have been associated with severe fetal and neonatal injury, such as hypotension, neonatal skull hypoplasia, anuria, renal failure and death. Along the same lines, the use of the angiotensin II receptor antagonists, such as valsartan, is not recommended because these agents cause fetal complications similar to the ACE inhibitors. -
Question 12 of 100
12. Question
1 pointsA 27 year old woman has shortness of breath and dyspnea when she jogs. She is diagnosed with exercise induced asthma and prescribed zileuton. Which location on the diagram below best describes the mechanism of action of this agent?
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Incorrect
Explanation:
There leukotriene pathway can be interrupted by inhibiting 5-lipoxygenase, thereby preventing leukotriene synthesis (action of zileuton) and by inhibiting the binding of LTD4 to its receptor on target issues thereby preventing its action (action of zafirlukast and montelukast). Zileuton selectively inhibits 5-lipoxygenase, an enzyme necessary´ for the conversion of arachidonic acid to leukotrienes. It is an orally active drug that is efficacious in exercise, aspirin-, and antigen- induced asthma. LTD4 is responsible for producing asthma symptomatology, such as bronchoconstriction, increased bronchial reactivity, mucosal edema, and mucus hypersecretion.
Glucocorticoids (option A) inhibit phospholipase A2
NSAIDs (option B) inhibit cyclooxygenase. There are also specific inhibitors of COX-2, e.g., COXibs, glucocorticoids. Zafirlukast and montelukast are leukotriene antagonists (option D). These agents are also used to treat asthma. -
Question 13 of 100
13. Question
1 pointsA 42 year old female presents with signs and symptoms of fibromyalgia. She would likely face which medication related side effects after the most appropriate therapy is instituted?
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Incorrect
Explanation:
Fibrositis (fibromyalgia) is most commonly seen in women between the ages of 20 and 50 and is associated with widespread chronic musculoskeletal pain (that improves with exercise), chronic fatigue, and sometimes severe headaches. Examination typically reveals painful trigger points produced by palpation of the trapezius and the lateral epicondyle of the elbow. Objective signs of inflammation are absent, and laboratory studies are normal. Patients with this disorder are likely to respond to treatment with tricyclic antidepressants on skeletal muscle relaxants with strong anticholinergic side effects, such as cyclobenzaprine. One of the most effective agents in the treatment of this disorder is amitriptyline, a tricyclic antidepressant commonly used in the treatment of depression and as an adjunctive pain medication. The tricyclic antidepressants are also associated with the development of strong anticholinergic side effects, such as dry mouth, tachycardia, urinary retention, and decreased gastrointestinal motility. The corticosteroids are associated with the development of adrenal suppression, immunosuppression, hypernatremia, hypocalcemia, and water retention. Prednisone is a corticosteroid indicated for the treatment of a variety of disorders caused by inflammation. Because this disease is not an inflammatory condition, prednisone would be not indicated for this patient.
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Question 14 of 100
14. Question
1 pointsA drug with oxytocic activity is given to a pregnant woman in order to induce cervical ripening. This agent, which is administered as a vaginal insert, contains prostaglandin E2. Which drug was administered to her?
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Incorrect
Explanation:
When given as a vaginal insert, dinoprostone (prostaglandin E2) causes the cervix to dilate and the uterus to contract. This prostaglandin softens the cervix by increasing proteoglycan content and changing the biophysical properties of collagen. Thus, dinoprostone is an effective labor inducing agent. This agent is approved for inducing abortion in the second trimester of pregnancy, for benign hydatidiform moles, and for ripening of the cervix for induction of labor in patients at or near term.
Alprostadil, or prostaglandin E1 is a vasodilator used to treat erectile dysfunction. Epoprostenol, which is used to treat pulmonary hypertension, causes vasodilation of pulmonary blood vessels. Latanoprost increases aqueous humor outflow and is therefore used in the treatment of glaucoma.
Misoprostol is an analogue of prostaglandin E1 used to prevent gastric and duodena ulcers caused by nonsteroidal anti-inflammatory drugs. -
Question 15 of 100
15. Question
1 pointsA 10 months infant presents with high fever, runny nose, wheezing and loss of appetite. The infant has lung problems due to prematurity. He is diagnosed with respiratory syncytial virus (RSV) infection. Which one of the following medication is indicated?
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Explanation:
Respiratory syncytial virus (RSV) can cause serious lower respiratory tract illness in infants, and incidence is particularly high during winter months. RSV is a paramyxovirus that causes annual outbreaks of pneumonia, bronchiolitis, and tracheobronchitis. In RSV bronchiolitis, proliferation and necrosis of bronchiolar epithelium occur, which produces obstruction from sloughed epithelium and increased mucus secretion. RSV infection is associated with fever, tachypnea, wheezes, hyperinflated lungs, decreased gas exchange, and labored breathing. It is important to note that RSV is the only respiratory pathogen that produces its most serious illness at a time when maternal antibodies are still present. Palivizumab is a monoclonal antibody directed against the fusion protein of RSV, thereby preventing infection of the host cell. Palivizumab exhibits neutralizing and fusion- inhibitory activity against RSV. This agent is directed at an epitope in the A antigenic site of the F protein on the surface of RSV. Abatacept is a selective costimulation modulator that inhibits T-cell activation and is indicated for rheumatoid arthritis. Daclizumab is a monoclonal antibody with high affinity for the IL-2 receptor on activated T cells. This drug is used to prevent tissue rejection in transplant patients. Prednisone induces lipocortin, which inhibits phospholipase activity and subsequent prostaglandin synthesis. Prednisone can also inhibit transcription of numerous proinflammatory cytokines. Sirolimus inhibits T-cell proliferation by binding a specific serine threonine kinase (mTOR), which is necessary for cell cycle progression.
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Question 16 of 100
16. Question
1 pointsA man has essential hypertension. He is starting diuretic therapy. A history of calcium oxalate renal stones is present. The diuretic that would be most appropriate for this patient is which one of the following?
Correct
Incorrect
Explanation:
A thiazide diuretic would be the drug of choice for this patient because it is the only class of diuretic that decreases urinary secretion of calcium. Thiazide diuretics, like hydrochlorothiazide, inhibit the Na+/Cl- cotransporter in the distal convoluted tubule and promote the reabsorption of calcium. Acetazolamide, a carbonic anhydrase inhibitor, and furosemide, a loop diuretic, induce diuresis at the expense of all three major cationic electrolytes (Na+, K+, and Ca2+), which are secreted in increased amounts. Spironolactone (choice D) and triamterene, so called potassium sparing diuretics, block Na+/K+ exchange in the collecting duct. Although they decrease K+ secretion, they elevate Na+ and Ca2+ secretion. -
Question 17 of 100
17. Question
1 pointsA 53 year old man with peptic ulcer disease has been on drug therapy for 3 months and has noticed changes in his bowel habits, increasing headaches, dizziness, skin rashes, loss of libido, and gynecomastia. The medication that is likely responsible for these side effects is
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Incorrect
Explanation:
Cimetidine, an H2-receptor antagonist, can produce all the side effects exhibited when taken in high doses over a long period of time. In addition, cimetidine can alter the hepatic metabolism of several drugs by inhibiting CYP450 enzyme. Famotidine is also an H2-receptor antagonist, but it does not have the side effects of cimetidine. Metronidazole is an antibacterial and antiprotozoal drug that may present with the adverse effects of headaches, dizziness, diarrhea, and rashes, but not gynecomastia. Omeprazole is a proton pump inhibitor, and sucralfate is a physical barrier to gastric acid. Neither has been associated with effects on sexual function or breast development. -
Question 18 of 100
18. Question
1 pointsA hypertensive male aged 56 years who had been treated with reserpine for many years. On a routine BP check, he was found to have an increase in blood pressure. When told about this, patient reported that since his visit he had taken an additional medication, and he admitted to recreational drug use. Which medication was likely responsible for his increase in blood pressure?
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Explanation:
Reserpine acts by blocking vesicular uptake of monoamine neurotransmitters (norepinephrine, dopamine, serotonin), thus making the neurotransmitter vulnerable to the catabolic effects of monoamine oxidase (MAO) present in the nerve terminal. High doses of reserpine can even destroy synaptic vesicles. Chronic administration of reserpine causes depletion of norepinephrine. Therefore, for a drug to raise blood pressure after norepinephrine depletion, it must act directly on the alphas adrenergic receptors present on arterioles. Phenylephrine, a direct alpha1 agonist, is such a drug. Amphetamine is an indirect acting sympathomimetic. It raises blood pressure by causing the release of endogenous norepinephrine. Bethanechol, a muscarinic agonist, decreases blood pressure by stimulating the noninnervated muscarinic receptors present on arterioles. Cocaine is an indirect acting sympathomimetic that raises blood pressure by blocking the reuptake of norepinephrine. Guanethidine is an adrenergic neuron blocker that acts by blocking the release of norepinephrine. -
Question 19 of 100
19. Question
1 pointsA drug is designed to lower cholesterol levels. Of the 1,000 patients who are involved in this study, half receive the drug and half receive a placebo. Neither the physicians in charge of the study nor the patients are permitted to know what the patients have received. Which step in the drug development process does this scenario most closely describe?
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Explanation:
Phase III trials consist of large, double blind, controlled studies using patients for whom the drug is targeted. Typically, 500-5,000 patients participate in the study, which is designed to determine whether the drug is more efficacious than placebo and to compare it with older therapies. Drug toxicity is also monitored; infrequent toxicities have a greater likelihood of appearing in this phase (because of the greater number of subjects) than the previous two phases.
For human testing to commence, an IND Application must be submitted by the manufacturer to the Food and Drug Administration (FDA). This application includes chemical and manufacturing information about the drug, data from animal testing, and designs for clinical testing. The NDA, which contains the results of the clinical studies, must be submitted following human testing to gain approval for general marketing of a drug for prescription use. Phase I trials are the first phase of clinical testing. Approximately 20 to 30 normal volunteers are used to determine the safety and pharmacokinetic properties of a new drug. Occasionally, patients are used in this phase (e.g., cancer patients who are tested with new chemotherapeutic agents). Phase II trials test a new drug on a small group of selected patients (100-300) with regard to therapeutic efficacy, dose range, kinetics, and metabolism. -
Question 20 of 100
20. Question
1 pointsA patient under treatment for a hypertensive crisis that occurred 2 hours ago is medicated with IV nitroprusside. The expected action of this drug is which one of the following?
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Incorrect
Explanation:
Nitroprusside is somewhat tricky to use, but is a very useful IV agent that causes dilatation of both arterioles and venules. It has a very rapid onset of action and is typically used in an emergency department or intensive care unit situation. The typical setting is a patient with acute or chronic low cardiac output and high ventricular filling pressures due to poor systolic left ventricular function. Underlying causes for the poor ventricular function may be diverse: malignant hypertension, dilated cardiomyopathy, acute myocardial infarction, chronic coronary heart disease, or aortic or mitral incompetence. Nitroprusside can improve perfusion of vital organs and reduce the work-load of the heart. Problems sometimes encountered with this drug include hypotension (best avoided by starting with a low dose and continuously monitoring systemic arterial and pulmonary capillary wedge pressures) and accumulation of toxic metabolites of cyanide in patients with liver or renal failure. Many physicians prefer to use IV nitrate rather than nitroprusside because of its lesser toxicity. -
Question 21 of 100
21. Question
1 pointsA 72-year-old man is treated for chest infection. For past 6 months,he is receiving Warfarin for atrial fibrillation with normal INR. However, his most recent INR was 5.2 (<1.4).Which one of the following drugs is responsible?
Correct
Incorrect
Explanation:
Clarithromycin induces the anticoagulant effect of warfarin, whereas rifampicin would reduce the anticoagulant effect. Ciprof1oxacin and sulphonamides will also increase the anticoagulant effect of warfarin. Temazepam, digoxin and codeine have no appreciable effect. -
Question 22 of 100
22. Question
1 pointsA 63-year-old female presents with deteriorating arthralgia associated with long-standing Rheumatoid arthritis. She was prescribed Celecoxib in place of naproxen. Which of the following concerning Celecoxib is correct?
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Incorrect
Explanation:
Celecoxib is a COX (Cyclo-oxygenase)-2 inhibitor differing from the other NSAIDs such as Naproxen which affects both COX-1 and COX-2. COX-1 is involved in platelet aggregation and inhibition of this by the NSAIDs produces its beneficial cardiovascular effects. However platelet aggregation is not affected by COX-2. Rofecoxib, Vioxx has been withdrawn due to its increased cardiovascular events compared with Naproxen. -
Question 23 of 100
23. Question
1 pointsA 76-year-old being treated for heart failure has potassium=6.9mEq/L. He was recently commenced on Amiloride. The interaction of Amiloride with which of his drugs listed below is likely to have caused the hyperkalaemia?
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Incorrect
Explanation:
The co-administration of a potassium-sparing diuretic and an ACE inhibitor, in this case Perindopril, may result in profound hyperkalaemia, as has occurred in this patient. Thus patients on both these drugs should have their potassium monitored closely. Metolazone may result in profound hypokalaemia. -
Question 24 of 100
24. Question
1 pointsWhich term best describes the affinity of a drug for its receptor?
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Explanation:
Affinity is the measure of the net molecular attraction between a drug (or neurotransmitter or hormone) and its receptor. The receptor´s affinity for binding a drug determines the concentration of drug required to form a significant number of drug-receptor complexes. Affinity and intrinsic are determinants of potency.
Efficacy contributes both to potency and to be the maximum effect of the agonist.
Efficacy is a measure of the efficiency of the drug-receptor complex in initiating the signal transduction process. -
Question 25 of 100
25. Question
1 pointsRegular hematologic monitoring for the development of granulocytopenia is required in patients who are being treated with which one of the following?
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Incorrect
Explanation:
Clozapine is one of the so-called second-generation antipsychotics, which are believed to be less likely to cause extrapyramidal side effects than the first-generation drugs such as haloperidol or the phenotiazines (e.g., fluphenazine). A 2003 meta-analysis concluded that clozapine was the most efficacious second generation antipsychotic, followed by risperidone and olanzapine. However, clozapine use is associated with an approximately 1% incidence of granulocytopenia or agranulocytosis. Early detection by monitoring blood counts every 1-2 weeks has led to a reduction in agranulocytosis-related death, but clozapine is generally considered second-line therapy, to be used in cases unresponsive to other drugs. -
Question 26 of 100
26. Question
1 pointsWhich of the following is a centrally acting antihypertensive agent?
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Incorrect
Explanation:
Moxonidine is centrally acting and is licensed for mild to moderate hypertension not controlled by beta blockers, ACE inhibitors, calcium channel antagonists and thiazides. Moxonidine is a selective agonist at the imidazoline subtype1 receptor. This receptor subtype is found in the medulla oblongata. Moxonidine causes a decrease in sympathetic nervous system activity and therefore, a decrease in blood pressure. Hexamethonium and trimethaphan are nicotinic blockers that act in the ganglia and are very efficacious but have too many side effects. Guanethidine and reserpine block adrenergic nerve terminals. -
Question 27 of 100
27. Question
1 pointsThe most helpful medication in a bulimic patient is
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Incorrect
Explanation:
Bulimia nervosa is recurrent episodes of binge eating followed by self- induced vomiting, laxative or diuretic abuse, vigorous exercise, or fasting.
Most symptoms and physical complications result from purging. Self- induced vomiting leads to erosion of dental enamel of the front teeth and to painless salivary gland enlargement. Serious fluid and electrolyte disturbances, especially hypokalemia, occur occasionally.
The diagnosis is suspected when patients express marked concern about weight gain and have wide fluctuations in weight, especially with excessive laxative use or unexplained hypokalemia. Swollen parotid glands, scars on the knuckles (from induced vomiting), and dental erosion are danger signs.
Treatment is with psychotherapy and SSRIs, especially fluoxetine. -
Question 28 of 100
28. Question
1 pointsWhich of the following is a typical side effect of Olanzapine?
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Incorrect
Explanation:
Akathisia is a typical side effect associated with the use of the atypical antipsychotic Olanazapine.
- Agranulocytosis
- Hyperprolactinemia
- Hyperglycemia
- Depression
- Anxiety
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Question 29 of 100
29. Question
1 pointsA 62 year old woman suffering from rheumatoid arthritis has been on long term therapy to control her disease. She now presents to you with history of increasing shortness of breath and a chest radiograph reveals “bilateral interstitial shadowing”. Investigations for infections were negative. Her symptoms are caused by which one of the following medications?
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Explanation:
Methotrexate is a recognized cause of pulmonary fibrosis. However, it is sometimes used in the treatment of idiopathic pulmonary fibrosis as a steroid sparing agent. “Pulmonary parenchymal or pleural reactions to chemotherapeutic agaents used in the management of patients with malignant disease are being recognized with increasing frequency. Alkylating agents, asparaginase, bleomycin, methotrexate and procarbazine have all been implicated” West J Med. 1977 October; 127(4): 292298. “Drug-related interstitial pneumonia should also be considered in rheumatoid arthritis patients on methotrexate or newer drugs such as lerlunomide. “Curr Opin Pulm Med 2006 Sep; 12 (5): 346-53. -
Question 30 of 100
30. Question
1 pointsWith which of the following is hyperprolactinaemia associated?
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Incorrect
Explanation:
Hyperprolactinaemia may manifest as a milky discharge from the breasts. The causes include:- Prolactinoma
- Hypothyroidism (far increased thyrotropin-releasing hormone [TRH])
- Non-functional tumour with stalk compression and
- Drugs, in particular dopamine antagonists such as chlorpromazine, haloperidol and domperidone or fluoxetine.
Pregnancy is a particularly common cause of hyperprolactinaemia. Other drugs that are occasionally reported include selective serotonin reuptake inhibitors (SSRIs). Polycystic ovary syndrome (PCOs) is often associated with idiopathic hyperprolactinaemia.
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Question 31 of 100
31. Question
1 pointsWhich of the following best describes the mode of action of Alendronate?
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Incorrect
Explanation:
Simple bisphosphonates such as clodronate and etidronate inhibit bone resorption through induction of osteoclast apoptosis. Clodronate, and perhaps etidronate, triggers apoptosis by generating a toxic analog of adenosine triphosphate, which then targets the mitochondria. For nitrogen-containing bisphosphonated, the direct intracellular target is the enzyme farnesyl diphosphate synthase in the cholesterol biosynthetic pathway. Its inhibition suppresses a processes required osteoclastic bone resorption. Although nitrogen containing bisphosphonates can induce osteoclast apoptosis, this is not necessary for their inhibition of bone resorption. -
Question 32 of 100
32. Question
1 pointsHypertensive encephalopathy is a serious complication of which of the following medications?
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Incorrect
Explanation:
The most common cause of hypertensive encephalopathy is abrupt blood pressure elevation in the chronically hypertensive patient. Other conditions predisposing a patient to elevated blood pressure can cause the same clinical situation. For example, ingestion of tyramine-containing foods or tricyclic antidepressants in combination with monoamine oxidase inhibitors (MAOIs). -
Question 33 of 100
33. Question
1 pointsA 30 year old lady returns to your office for a 6 week follow-up for depression. She started fluoxetine (Prozac) six weeks ago and she now complains that her libido has become worse which was already decreased when she started the drug. Which of the following strategy would be appropriate?
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Explanation:
Fluoxetine and other SSRIs (e.g. sertraline) can cause or worsen loss of libido. This is also true with tricyclics such as imipramine. Bupropion does not inhibit libido. -
Question 34 of 100
34. Question
1 pointsAll of the following are side effects of methylphenidate (Ritalin), except
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Explanation:
Ritalin is the most frequently prescribed stimulant drug for Attention Deficit Disorders. Possible side effects of Ritalin include reduced appetite, headache, sleep difficulty, anxiety, increased blood pressure and heart palpitations. -
Question 35 of 100
35. Question
1 pointsA common early side effect of fluoxetine (Prozac) is
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Incorrect
Explanation:
Fluoxetine, a selective serontonin reuptake inhibitor, has no effect on the norepinephrine system; therefore, it does not produce the side effects common to the tricyclic antidepressants. These include antibolinergic side effects (dry mouth, constipation), orthostatic hypotension, cardiac conduction disturbances, and drowsiness. Loss of appetite is often seen in patients who take fluoxetine, and can be especially troublesome in the elderly. Skin rash is uncommon. -
Question 36 of 100
36. Question
1 pointsA patient is brought to the emergency with ingestion of 20 tablets of Acetaminophen. The antidote of choice is
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Incorrect
Explanation:
N-acetylcysteine regenerates glutathione and prevents toxic metabolism of acetaminophen. Ethanol is an antidote for ethylene glycol and methanol toxicity. Glucagon is an antidote for beta-blocker toxicity. Methylene blue is an antidote for methemoglobinemia, which can occur after the ingestion of nitrites, nitropruside, dapsone, or antimalarials. Naloxone is an antidote to opioids. -
Question 37 of 100
37. Question
1 pointsA beta blocker that exerts its effect by slowing the ventricular rate.
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Incorrect
Explanation:
Propranolol is the only beta-blocker listed and it works by binding to beta receptors in the ventricle to directly slow the ventricular rate. -
Question 38 of 100
38. Question
1 pointsAll of the following medications can cause renal dysfunction EXCEPT
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Explanation:
Amiodarone is an anti-arrhythmic agent which has many side effects. Some of them are thyroid abnormalities, pulmonary fibrosis, hepatitis, and prolongation of the Q-T interval. Renal abnormalities are not seen. Nonsteroidal anti-inflammatory drugs and Methicillin can cause renal dysfunction with interstitial nephritis. Aminoglycosides cause oliguric nephrotoxicity in large doses and may even cause tubular necrosis. Amphotericin B is an anti-fungal drug which can cause renal dysfunction in high cumulative doses. It can also cause renal tubular acidosis. Allopurinol is used to prevent uric acid production and it can cause interstitial nephritis. -
Question 39 of 100
39. Question
1 pointsThe anti tuberculous drug that causes optic neuritis is which one of the following?
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Incorrect
Explanation:
Isoniazid causes both liver damage and peripheral neuropathy (the neuropathy can be prevented with B6 supplementation). Ethambutol may cause an optic neuritis (decreased green color perception, reduced visual acuity). Streptomycin, like all aminoglycosides, may be ototoxic. Rifampin´s side effects include rash, hepatitis, and mild GI disturbance. Pyrazinamide´s major side effect is hepatotoxicity. -
Question 40 of 100
40. Question
1 pointsA pharmacologist is gathering pharmacokinetic data during clinical trials of a new antimicrobial agent. The half-life of this drug as determined by him is 4 hours. A continuous intravenous drip was started 24 hours ago at a rate of 10 mg/min. Blood tests after 24 hours reveal that the patient´s drug plasma concentration is 20 mg/L. The clearance of this agent is
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Incorrect
Explanation:
You must be familiar with the maintenance dose equation to answer this question:
MD = Cl x Cpss /F, where
MD = maintenance dose
CI = clearance
Cpss = plasma concentration at steady ─ state
F = bioavailability
In this case, MD is 10 mg/min; F, or how much drug is absorbed, is 1 (100%) because drugs administered IV are completely absorbed. (F becomes important when drugs are given orally.) CpSS = 20 mg/L; it takes four to five half-lives to achieve steady-state, so this drug has been administered for a time period equaling six half-lives.
Solving,
10 mg/mL = Cl x20 mg/mL
Cl= 0.5 L/min -
Question 41 of 100
41. Question
1 pointsA 66 year old with a documented penicillin and macrolide allergy is diagnosed with Lyme disease. She also has chronic renal failure. Most appropriate for this patient is which one of the following?
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Incorrect
Explanation:
Tetracyclines, such as doxycycline, are antibiotics commonly used to treat rickettsial infections, such as Rocky Mountain spotted fever and typhus, and Lyme disease caused by a spirochete. They are also used for acne various sexually transmitted diseases, and for susceptible organisms in penicillin allergic patients. Doxycycline and minocycline are tetracyclines excreted largely by non-renal routes. Their half lives and serum concentrations are net significantly increased in patients with renal Impairment. Both doxycycline and minocycline are secreted in an inactive form into the Intestinal lumen and eliminated in the feces; therefore their half lives are largely independent of renal function. The other tetracyclines listed are concentrated by the liver the bile and excreted in the urine and feces unchanged. Therefore dosage adjustments need to be made in patients with renal impairment because of the accumulation of the drug in the body. In other words demeclocycline, methacycline, oxytetracycline, and tetracycline will accumulate in patients with renal impairment. Hence doxycycline would be the best treatment option for this patient. -
Question 42 of 100
42. Question
1 pointsA 39 year old man has had his blood pressure measured on three different occasions in the clinic, yielding values of 145/95, 160/105, and 150/100 mm Hg. Careful history indicates that he has problems with asthma since childhood. Decision to treat the patient with a beta-blocker is made. The physician should prescribe which one of the following?
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Incorrect
Explanation:
Beta 1 selective antagonists are often used to control hypertension in patients, such as asthmatics, who might experience bronchoconstriction with nonselective beta antagonists (e.g. propranolol). Remember that beta 1 receptors predominate in the heart, while beta2 receptors predominate in the lungs. A mnemonic to help you remember the main beta 1 blockers is: Beta blockers begining with the letters A through M are beta-1 selective, and the ones beginning with the letters N through Z are beta nonselective. Remember that the letter C (carvedilol) and L (labetalol) are exceptions. Labetalol blocks alpha, beta1, and beta2 receptors and is useful in treating hypertensive emergencies and the hypertension of pheochromocytoma. Nadolol blocks both beta1 and beta2 receptors and is known for its very long half life (14 to 24 hours). Prazosin blocks alpha1 receptors and is used primarily in the treatment of hypertension. Timolol blocks both beta1 and beta2 receptors and is frequently used for the treatment of open-angle glaucoma. -
Question 43 of 100
43. Question
1 pointsA patient with kidney transplant aged 45 years is being treated with sirolimus. In addition to headache and nausea, what is the most likely side effect to occur in him?
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Incorrect
Explanation:
Sirolimus inhibits T-cell proliferation by binding mTOR, a serine- threonine kinase instrumental in cell cycle progression. Hyperlipidemia is a particular concern in renal patients. Other common side effects include thrombocytopenia and leukopenia. Additional serious adverse effects associated with sirolimus include atrial fibrillation, heart failure, hypervolemia, and palpitations. Cytokine release syndrome is associated with muromonab-CDS therapy. Hepatotoxicity can occur with either cyclosporine or azathioprine. Nephrotoxicity is primarily a concern when sirolimus and cyclosporine are taken together (within 24 h of each other). Cyclosporine and tacrolimus are limited by nephrotoxicity and can be associated with neurotoxicity. -
Question 44 of 100
44. Question
1 pointsA 47 year old female presents to have a mole removed. She had an allergic reaction to a local anesthetic the last time she had dental work performed. She received procaine for a tooth extraction. Which drug would be appropriate for the present procedure?
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Explanation:
There are two classes of local anesthetics: esters and amides. The rule of thumb is that; If you are allergic to one drug of given class (usually the ester class), you also will be allergic to other drugs of the same class. The proper course of action would be to switch over to the other drug class. In this question, the patient received procaine which is an ester. Therefore, you need to identify the amide in the list of answers. The only amide listed is mepivacaine. Other amide local anesthetics include lidocaine, bupivacaine, etidocaine, prilocaine, and ropivacaine. An easy way to distinguish between the amides and esters are as follows: the amides have two” I´s” in their names and the esters have either one or no “I´s” in their name. -
Question 45 of 100
45. Question
1 pointsA 46 year old man with venous thromboembolism is started on an agent that accelerates the activity of antithrombin III to inactivate thrombin. Several days later, profound hematuria is noted. Agent indicated to treat his current condition is
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Explanation:
This patient received heparin, which acts by accelerating the activity of antithrombin III (ATIII) to inactivate thrombin; however heparin does not lyse existing clots. Protamine sulfate is a positively charged basic protein that inactivates heparin, which is negatively charged. Inactivation of heparin stops the bleeding. Protamine sulfate binds to heparin and forms an inactive salt compound. Side effects of protamine sulfate include hypotension, pulmonary edema, and anaphylaxis. Aminocaproic acid competitively blocks plasminogen activation and is therefore used to treat bleeding induced by Fibrinolytic agents. Aspirin inhibits platelet aggregation and is used to prevent thromboembolic disorders. Enoxaparin is a low molecular-weight heparin that potentiates antithrombin III; thus, as with heparin, it can cause bleeding and thrombocytopenia. Urokinase is a fibrinolytic drug and therefore convert´s plasminogen to plasmin, which subsequently degrades the fibrin clot. -
Question 46 of 100
46. Question
1 pointsA 35 year old woman is diagnosed with generalized anxiety disorder. The pharmacologic treatment for her condition that will most likely produce the fewest the fewest side effects is which one of the following?
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Explanation:
Generalized anxiety disorder is the term reserved for patients who have had excessive, virtually daily, anxiety about many activities and events for more than 6 months. This condition affects 3% to 5% of the general population, and often begins in childhood or adolescence. The condition is also characterized by restlessness, unusual fatigability, difficulty concentrating, irritability, and difficulty sleeping. The level of anxiety is often exhausting, and these patients may do poorly in their environment because of difficulties with concentration and fatigue. Behavioral therapy is usually ineffective. While tricyclics and benzodiazepines had traditionally been used for treatment, both selective serotonin reuptake inhibitors (SSRIs) and buspirone are becoming first line therapy due to their lower side effect profiles. Many physicians who treat these patients start them on benzodiazepines (that act quickly) and then switch them to buspirone (which does not cause dependency but takes about 2 weeks to work). Sumatriptan is a serotonin receptor agonist. It is mainly used for acute migraines and cluster headache attacks. Its half life is less than 2 hours. Thiopental is a barbiturate that facilitates GABA function by increasing the duration of Cr channel opening. While barbiturates can be used as sedatives, thiopental is most commonly used for induction of anesthesia. -
Question 47 of 100
47. Question
1 pointsA 47 year old man presents for evaluation 3 months after starting on an antihypertensive medication. His blood pressure is 128/83 mm Hg. Lipid profile is: total cholesterol 280 mg/dL, HDL 34 mg/dL, LDL 188 mg/dL, and triglycerides 191 mg/dL. His lipid profile was normal prior to beginning his antihypertensive medication. Which medication is most likely caused his dyslipidaemia?
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Explanation:
The question states that the patient began antihypertensive therapy 3 months earlier and now elevated total cholesterol, LDL and triglyceride levels, as well as a low HDL level. Therefore, there is a strong possibility that the antihypertensive medication caused the dyslipidemia. Metoprolol is a beta adrenergic blocking agent that is known to cause dyslipidemia in patients. Although thiazides also cause hyperlipidemia, none of the other medications given as choices are associated with the development of dyslipidemias. The ACE-inhibitor benazepril and the calcium channel blocker diltiazem are both used to treat essential hypertension and are not associated with the development of dyslipidemias. Both clonidine a centrally acting alpha 2 -receptor agonist, and prazosin a peripherally acting alpha receptor blocking agent, can be used to treat hypertension. However, due to their side effect profiles, these agents are generally used in patients unresponsive to other antihypertensive therapies. -
Question 48 of 100
48. Question
1 pointsThe mechanism that best describes the action by which Botox (botulinum toxin) weakens the muscle is which one of the following?
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Explanation:
Botulinum toxin is a protein toxin produced by the gram positive, spore forming, obligate anaerobe Clostridium Botulinum. Botulinum toxin type A blocks neuromuscular conduction by binding to receptor sites on motor nerve terminals, entering nerve terminals, and inhibiting the release of acetylcholine (ACh). Inhibition of ACh release occurs because the neurotoxin cleaves a protein (SNAP-25) that is essential to the successful docking and release of acetylcholine from vesicles located within nerve endings. After intramuscular injection of Botox, botulinum toxin type A produces partial chemical denervation of the muscle, resulting in a localized reduction in muscle activity. Additionally, the muscle may atrophy, axonal sprouting may occur, and extra-junctional acetylcholine receptors may be expressed. Botulinum toxin does not block nicotinic cholinergic receptors, it prevents ACh release. Local anesthetics, such as lidocaine, block voltage-gated sodium channels in neurons. Dantrolene inhibits calcium release from intracellular stores. Choline, rather than acetylcholine, is taken up into neurons through a high-affinity choline uptake transporter, and this transporter is inhibited by hemicholinium. -
Question 49 of 100
49. Question
1 pointsA surgeon excises a breast lump of a 45 year old female and also notices nodal involvement. The tumor has estrogen receptors and she is started on tamoxifen therapy. She has increased risk of which one of the following?
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Explanation:
Some breast cancers show sufficient differentiation to display estrogen receptors. Tumors that display these receptors may rely on estrogen stimulation for survival. Thus, treatment of these tumors includes blocking estrogen receptors with tamoxifen, a selective estrogen receptor modulator (SERM). Because the tumor depends on estrogen signaling, it regresses. Tamoxifen, however, is a partial agonist to the estrogen receptor. Stimulation of the estrogen receptor by tamoxifen increases the risk of endometrial cancer in patients receiving the drug. As a side note, raloxifene is another SERM that does not increase the risk of endometrial cancer; it is also indicated for the treatment and prevention of osteoporosis. Contralateral breast cancer, endometriosis, leiomyoma and leukemia are not associated with tamoxifen therapy. -
Question 50 of 100
50. Question
1 pointsA liver transplant patient aged 42 years is identified as having an increased risk for renal dysfunction. The immunosuppressive therapy selected includes prednisone, mycophenolate mofetil, and a drug that inhibits T-cell activation and proliferation. Which is most likely the identity of the third drug?
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Explanation:
Sirolimus inhibits Tcell proliferation by binding a specific serine-threonine kinase (mTOR), which is necessary for cell cycle progression. Cyclosporine and tacrolimus inhibit calcineurin-mediated transcription of IL-2 and subsequently reduce I cell activation. Cyclosporin and tacrolimus are limited by nephrotoxicity, whereas sirolimus has the advantage of minimal nephrotoxicity. However, sirolimus synergistically enhances cyclosporine-induced nephrotoxicity.
Cyclophosphamide inhibits cell proliferation by alkylating DNA. Methotrexate is also an antimetabolite which inhibits DNA synthesis. Nephrotoxicity is not a primary concern with either cyclophosphamide or methotrexate. -
Question 51 of 100
51. Question
1 pointsA 20 year old girl presents with nausea, vomiting, and weight gain. Her urine tests positive for hCG. She has been compliant with her oral contraception use. Her medical history is significant for asthma, hypothyroidism, and positive PPD test 2 months ago. Which drug interfered with her contraceptive method?
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Explanation:
Rifampin is an antituberculosis agent that can be given as part of treatment for latent tuberculosis (diagnosed by a positive PPD test) in a 4 month course along with isoniazid. However, rifampin also increases cytochrome P450 activity, and thus promotes the metabolism of oral contraceptive medications. Physicians must therefore advise patients to use alternative forms of contraception while taking rifampin. Fluticasone is an inhaled corticosteroid for asthma. It has no known effect on, hormonal contraception effectiveness. Isoniazid, like rifampin, is an antituberculosis agent. However, it has no interactions with oral contraceptives. In fact, isoniazid is known to reduce P450 activity and may, in principle, promote the efficacy of oral contraceptives. Levothyroxine is a thyroid replacement medication used to treat hypothyroidism. There is no contraindication for its concurrent use with oral contraceptives. Phenytoin is an antiseizure medication that also increases cytochrome P450 activity and reduces oral contraception effectiveness. However, since the question does not mention a history of seizures, it is not likely that this patient would be taking this medication. -
Question 52 of 100
52. Question
1 pointsA 36 year old male with fever, chills,WEIGHT LOSS AND
night sweats is diagnosed with lymphoma. He is started on chemotherapy, including Cyclophosphamide. What is its mechanism of action?
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Explanation:
Cyclophosphamide is an alkylating agent that causes DNA crosslinking. Cyclophosphamide is used to treat non-Hodgkin lymphoma, breast cancer, and ovarian carcinomas. Its toxicities include hemorrhagic cystitis and myelosuppression. Blocking microtubule formation is the mechanism of action of vinblastine and vincristine. These alkaloids, derived from the genus Vinca bind tubulin and prevent polymerization into microtubules. Thus, the chromosomes cannot be separated into daughter cells and cell division cannot be completed. Inhibiting purine synthesis is the mechanism of action of 6-mercaptopurine. This agent, used to treat leukemia and lymphoma, causes bone marrow and gastrointestinal toxicity. Inhibiting pyrimidine synthesis is not the mechanism of action of cyclophosphamide. DNA intercalation is accomplished by several cancer chemotherapeutic agents, including bleomycin and doxirubicin. -
Question 53 of 100
53. Question
1 pointsA 69 year old female´s only complaint is mild, occasional swelling in her ankles. Serum sodium is 139 mEq/L; potassium is 3.5 mEq/L; and chloride is 105 mEq/L. A diuretic is prescribed. The most likely target of this medication is which one of the following?
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Explanation:
Potassium is responsible for maintenance of intracellular tonicity, transmission of nerve impulses, contraction of muscle (striated and smooth), and maintenance of renal function. The normal blood level of potassium ranges from 3.5 to 5.0 mEq/L. In potassium depletion, a decrease in the blood potassium level of 1 mEq/L equals a loss of 100-200 mEq from potassium stores in the body. Depletion can result in the development of muscular weakness, paralysis, and mental confusion. Since this patient is borderline hypokalemic, she most likely received a potassium sparing diuretic, such as spironolactone, amiloride, or triamterene. Among these, spironolactone acts as a competitive antagonist of the aldosterone receptor in the cortical collecting tubule, while triamterene and amiloride act at the same part of the tubule by blocking sodium channels. Drugs, such as acetazolamide inhibit carbonic anhydrase which causes a self limited bicarbonate diuresis and reduction in total body bicarbonate stores. Thiazide diuretics, such as hydrochlorothiazide, inhibit NaCl reabsorption in the early distal convoluted tubule. Loop diuretics, such as furosemide, act on the Na+ /K+/Cr- cotransporter in the thick ascending limb of the loop of Henle (hence “loop” diuretics). Tubular fluid osmolarity can be changed by osmotic diuretics, such as mannitol. -
Question 54 of 100
54. Question
1 pointsA hospitalized patient with dysuria and suprapubic pain is treated with ciprofloxacin. The mechanism of action of this antibiotic is which one of the following?
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Explanation:
This is a straightforward question in which the introductory clinical details are really irrelevant. Ciprofloxacin and norfloxacin belong to a category of antibiotics called the fluoroquinolones. They are bactericidal and work by inhibiting topoisomerase II (DNA gyrase). They are effective against gram negative rods and are the only oral agents effective against Pseudomonas. Ciprofloxacin is effective for treating urinary tract infections, gonorrhea, diarrheal diseases, and soft tissue infections. It is also used to treat Pseudomonas infections in cystic fibrosis. Inhibition of dihydrofolate reductase is the mechanism of action of trimethoprim, which is typically used in combination with sulfonamides (trimethoprim-sulfamethoxazole). Sulfonamides inhibit an earlier step in folate synthesis (dihydropteroate synthase), so the combination with trimethoprim is an effective “one-two” punch. Trimethoprim-sulfa is used in the treatment of Shigella, Salmonella, recurrent urinary tract infections, and Pneumocystis carinii pneumonia. Inhibition of DNA-dependent RNA polymerase is the mechanism of action of rifampin. Rifampin is used (along with other drugs) in the treatment of tuberculosis. You should also remember that rifampin can be used to treat individuals exposed to the meningococcus or Haemophilus influenzae type B. Inhibition of the 30S ribosomal subunit is the mechanism of action of two important classes of antibiotics the tetracyclines (tetracycline, doxycycline, demeclocycline) and the aminoglycosides (gentamicin, tobramycin, streptomycin, etc.). The tetracyclines inhibit the attachment of the aminoacyl tRNA to the ribosome, whereas the aminoglycosides inhibit the formation of the initiation complex. Inhibition of the 50S ribosomal subunit is the mechanism of action of the macrolides (e.g., erythromycin), the lincosamides (e.g., lincomycin, clindamycin), and chloramphenicol. Chloramphenicol inhibits the 50S peptidyl transferase, whereas erythromycin blocks translocation. -
Question 55 of 100
55. Question
1 pointsA physiologist is studying the consequences of diminished brain perfusion in an experimental animal. Carotid artery is occluded, and brain function is monitored by positron emission tomography. Which drug would be effective in reversing the change in heart rate produced by the experimental occlusion?
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Explanation:
The first thing that you have to know is the effect that carotid occlusion will have on this animal. A carotid occlusion blocks blood flow to the carotid baroreceptors, thereby simulating a low blood pressure. The animal´s response will be to initiate a baroreceptor response, which will increase sympathetic output and decrease parasympathetic output. The net result will be an increase in blood pressure and heart rate. The second thing to determine is which drug will oppose this increase in heart rate. Propranolol, a nonspecific beta antagonist, will prevent norepinephrine from acting on the beta, receptors on the heart following an increase in sympathetic output, thus opposing the reflex increase in heart rate. Atropine, a muscarinic antagonist, might further increase heart rate. However, because part of the baroreceptor reflex involves withdrawing parasympathetic output, the effect of atropine would be negligible. Metaproterenol, a beta2 agonist, does not have much of a direct effect on heart rate because the predominant adrenergic receptor on the heart is beta1. Metaproterenol decreases blood pressure by producing vasodilatation in the skeletal muscle vasculature, which is sensed at the aortic arch baroreceptors. This in itself elicits a baroreceptor reflex that is additive to the reflex produced by the carotid occlusion. Neostigmine, a carbamylating acetyl cholinesterase inhibitor, may slow the heart slightly. However, because parasympathetic output is withdrawn during a carotid occlusion, there is not a sufficient amount of acetylcholine present even if its metabolism is prevented by a cholinesterase inhibitor. Phenoxybenzamine, an alpha adrenergic antagonist, does not affect heart rate directly because there are no alpha adrenergic receptors in the heart. It acts to decrease blood pressure by blocking alpha receptors in the vasculature. This true decrease in blood pressure is sensed by the aortic arch baroreceptors, contributing further to the baroreceptor reflex initiated by the carotid occlusion and further increasing heart rate. -
Question 56 of 100
56. Question
1 pointsA 25 year old farmer is rushed to a nearby emergency department after exposure to parathion. He is in respiratory distress and is bradycardic. Which of the following drugs can be given to increase the activity of his acetylcholinesterase?
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Explanation:
Pralidoxime (2-PAM) is an acetylcholinesterase (AChE) reactivating agent. It is useful only for counteracting AChE inhibitors that act by phosphorylating the enzyme (organophosphates). Pralidoxime can remove the phosphate group from AChE, thus regenerating the enzyme. This must be done in a timely fashion because normally after the phosphate group is bound to the enzyme, it undergoes a chemical reaction known as “aging.” Once this bond ages, pralidoxime will no longer be effective. Atropine is a nonselective muscarinic antagonist. Although atropine would be an appropriate agent for this patient, it acts by preventing the excess ACh from stimulating muscarinic receptors rather than altering the activity of AChE. Deferoxamine is a chelator used for iron poisoning.
Dimercaprol is a chelator used alone for arsenic, mercury, and gold poisoning. It is also used in conjunction with edetate calcium disodium (EDTA) to treat severe lead poisoning. N-acetylcysteine is used to treat acetaminophen overdose. -
Question 57 of 100
57. Question
1 pointsA patient has been given an anticoagulant. Which one of the following finding that suggests that he was given warfarin, not heparin?
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Incorrect
Explanation:
The following chart summarizes the differences between heparin and warfarin:Heparin Warfarin Increased effect of antithrombin III on thrombin Interferes with synthesis of vitamin K clotting factors Monitored by PTT Monitored by PT Given IV or SQ Given orally Toxicity treated with protamine sulfate Toxicity treated with vitamin K and fresh frozen plasma Rapid anticoagulation 2-3 days before anticoagulation Can be used in pregnancy Can´t be used in pregnancy -
Question 58 of 100
58. Question
1 pointsA 31 year old pregnant female has a history of rheumatoid arthritis, which has been managed successfully with NSAIDs. She has recently visited her general practitioner complaining of burning epigastric pain worsened by food intake. Which ulcer medication is most likely contraindicated in her?
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Explanation:
Although misoprostol would be best indicated in NSAIDs induced ulcers, prostaglandin analogs are abortifacient and are contraindicated during pregnancy. Famotidine is an H2 blocker that does not affect liver metabolism. Misoprostol is a prostaglandin E1 analog used in peptic ulcer disease. It does not affect hepatic metabolism. Omeprazole is a proton pump inhibitor used to decrease acid production in patients with peptic ulcer disease or reflux. It does not affect drug metabolism by the liver. Ranitidine is another H2 blocker. It does not inhibit liver enzymes as strongly as cimetidine does. -
Question 59 of 100
59. Question
1 pointsA 33 year old is spraying malathion on trees. While resting, he reaches down to grab his drink and accidentally takes a swig of malathion instead. He is quickly taken to emergency department. Which drug could be given to induce emesis?
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Explanation:
Apomorphine is a dopamine and opioid agonist that stimulates the chemoreceptor trigger zone in the medulla of the brainstem to induce vomiting. It must be administered parenterally and, because it is a respiratory depressant, it should not be given to patients with compromised respiration. If necessary, the apomorphine induced respiratory depression can be reversed by naloxone. Loperamide is an over the counter antidiarrheal. Metoclopramide is a dopamine receptor antagonist used to stimulate upper gastrointestinal motility. Because it is a dopamine antagonist, it also acts as an antiemetic used in chemotherapy. Ondansetron, a 5HT3 antagonist, is an antiemetic. Ranitidine, an H2 antagonist, reduces histamine-induced gastric acid release. -
Question 60 of 100
60. Question
1 pointsA 52-year-old man is being treated for hypertension and epilepsy and has been told by his dentist that he has gingival hyperplasia. Which of the following medications is the most likely to be the cause?
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Explanation:
Gingival enlargement may also be associated with the administration of three different classes of drugs, all producing a similar response:
- Anticonvulsants (such as phenytoin, phenobarbital, lamotrigine, valproate, vigabatrin, ethosuximide, topiramate and primidone)
- Calcium channel blockers, such as nifedipine and verapamil. The dihydropyridine derivative isradipidine can replace nifedipine and does not induce gingival overgrowth.
- Ciclosporin, an immunosuppresant.
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Question 61 of 100
61. Question
1 pointsAll of the following are features of cannabinoids except?
Correct
Incorrect
Explanation:
Cannabinoids are derived from the resin of Cannabis sativa and 9-tetrahydrocannabinol (9-THC) is its most important pharmacologically active constituent. If cannabis is ingested, 25-50% of the cannabinoids are absorbed, with effects occurring 0.5-3 hours later. Naloxone and other opioid receptor antagonists block the analgesic actions of cannabinoids. Synthetic cannabinoids reduce arachidonic acid-induced inflammation by inhibiting eicosanoid production. -
Question 62 of 100
62. Question
1 pointsA 63-year-old female presents with deteriorating arthralgia associated with long-standing Rheumatoid arthritis. She was prescribed Celecoxib in place of naproxen. Which of the following concerning Celecoxib is correct?
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Incorrect
Explanation:
Celecoxib is a COX (Cyclo-oxygenase)-2 inhibitor differing from the other NSAIDs such as Naproxen which affects both COX-1 and COX-2. COX-1 is involved in platelet aggregation and inhibition of this by the NSAIDs produces its beneficial cardiovascular effects. However platelet aggregation is not affected by COX-2. Rofecoxib, Vioxx has been withdrawn due to its increased cardiovascular events compared with Naproxen. -
Question 63 of 100
63. Question
1 pointsA 76-year-old being treated for heart failure has potassium=6.9mEq/L. He was recently commenced on Amiloride. The interaction of Amiloride with which of his drugs listed below is likely to have caused the hyperkalaemia?
Correct
Incorrect
Explanation:
The co-administration of a potassium-sparing diuretic and an ACE inhibitor, in this case Perindopril, may result in profound hyperkalaemia, as has occurred in this patient. Thus patients on both these drugs should have their potassium monitored closely. Metolazone may result in profound hypokalaemia. -
Question 64 of 100
64. Question
1 pointsA 29 year old man was bitten by a rattlesnake. He presents to Emergency Department after 2 hours with complains of weakness, abdominal cramping, left leg pain, and left leg swelling. He has slurred speech and his breath smells of alcohol. Physical Findings: Temperature 37.0°C (98.6°F), Blood pressure 100/60 mm Hg, Pulse 122 beats/min, Respirations 24/min – Skin diaphoretic; ecchymoses on both forearms; Extremities visible swelling of left leg and thigh; bite puncture site just above left lateral malleolus; skin tightness of left leg which one of the following therapeutic interventions is indicated?
Correct
Incorrect
Explanation:
This patient presents with a history of snakebite, swelling of an entire extremity, weakness, and ecchymosis. This is consistent with a grade III envenomation and merits antivenin therapy. Production of equine-derived antivenin has stopped, but may still be indicated where available. The ovine product, CroFab, is less allergenic but still scarce due to limited production.
Venom extractors are thought to be useful only in the first few minutes after a bite. Two hours is too late to be of any use. Tourniquets are thought to be contraindicated when used to compress an artery. Low- pressure constriction of lymphatic and venous vessels is controversial. Fasciotomy has not proved useful. Antivenin is indicated before any consideration of compartment syndrome. Pressure measurements would be required because of the clinical similarities between envenomation injury and compartment syndrome. Coagulation factors and blood products are rapidly inactivated. They are indicated only in the presence of exsanguinations. -
Question 65 of 100
65. Question
1 pointsAll of the following neurological symptoms are produced by antipsychotics, except
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Incorrect
Explanation:
Conventional antipsychotics produce several adverse effects, such as sedation, cognitive blunting, dystonia and muscle stiffness, tremors, elevated prolactin levels, and weight gain. Akathisia (motor restlessness) is particularly unpleasant and may lead to noncompliance. These drugs may also cause tardive dyskinesia, an involuntary movement disorder most often characterized by puckering of the lips and tongue and/or writhing of the arms or legs. The incidence of tardive dyskinesia is about 5%/year of drug exposure among patients taking conventional antipsychotics. In about 2%, tardive dyskinesia is severely disfiguring. In some patients, tardive dyskinesia persists indefinitely, even after the drug is stopped. -
Question 66 of 100
66. Question
1 pointsRegular hematologic monitoring for the development of granulocytopenia is required in patients who are being treated with which one of the following?
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Incorrect
Explanation:
Clozapine is one of the so-called second-generation antipsychotics, which are believed to be less likely to cause extrapyramidal side effects than the first-generation drugs such as haloperidol or the phenotiazines (e.g., fluphenazine). A 2003 meta-analysis concluded that clozapine was the most efficacious second generation antipsychotic, followed by risperidone and olanzapine. However, clozapine use is associated with an approximately 1% incidence of granulocytopenia or agranulocytosis. Early detection by monitoring blood counts every 1-2 weeks has led to a reduction in agranulocytosis-related death, but clozapine is generally considered second-line therapy, to be used in cases unresponsive to other drugs. -
Question 67 of 100
67. Question
1 pointsWhich of the following is a typical side effect of Olanzapine?
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Incorrect
Explanation:
Akathisia is a typical side effect associated with the use of the atypical antipsychotic Olanazapine.
- Agranulocytosis
- Hyperprolactinemia
- Hyperglycemia
- Depression
- Anxiety
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Question 68 of 100
68. Question
1 pointsOut of the following, which drug which works by inhibiting the tumor necrosis factor (TNF)?
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Incorrect
Explanation:
Montelukast works as leukotriene receptor antagonists, and is used in treatment of asthma. Etanercept and infliximab inhibit TNF and are licensed in the treatment of rheumatoid arthritis. Infliximab is given with methotrexate and is associated with development of tuberculosis.
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Question 69 of 100
69. Question
1 pointsA 33 year old engineer has been uncharacteristically active for several weeks. He spends most of his time at work and gets little sleep. He has told another engineer that he is involved “in a research project that will earn me the Nobel Prize”. The engineer is irritable, and it is hard to hold his attention. His classmate from graduate school recalls that the patient behaved in a similar manner twice during stressful periods at school. Which of the following drug therapy would be appropriate in this patient for long term?
Correct
Incorrect
Explanation:
Schizophrenia is characterized by psychosis (loss of contact with reality), hallucinations (false perceptions),-delusions (false beliefs), disorganized speech and behavior, flattened affect (restricted range of emotions), cognitive deficits (impaired reasoning and problem solving), and occupational and social dysfunction. The cause is unknown, but evidence for a genetic component is strong. Symptoms usually begin in adolescence or early adulthood. One or more episodes of symptoms must last 2-6 months before the diagnosis is made. Treatment consists of drug therapy (haloperidol, clozapine), psychotherapy and rehabilitation. -
Question 70 of 100
70. Question
1 pointsThe drug that is contraindicated with tyramine rich food (eg cheese) is
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Incorrect
Explanation:
Phenelzine (sold as Nardil) is a monoamine oxidase inhibitor (MAOI) used as an antidepressant drug. As with other MAOIs, tyramine containing foods cause a hypertensive crisis, so users of phenelzine should adhere to certain dietary guidelines, primarily consisting of avoiding certain aged wines and spirits, and certain aged cheeses. The prescribing physician will advise patients on this issue. The tyramine induced hypertensive crises is estimated to effect only a few percent of the population. It is possible to test patients to see if they are at risk. -
Question 71 of 100
71. Question
1 pointsA drug that will cause hemolytic disease and resultant jaundice in all individuals in high dose is which one of the following?
Correct
Incorrect
Explanation:
Drugs such as phenacetin, acetanilide, alpha-methyldopa, and other organic substances such as lead and arsenic will cause hemolysis in every individual. However, drugs such as p-amino salicylates (C), sulfonamides (B), anti-malarial drugs (E), penicillin (A), and streptomycin will only cause hemolysis in sensitive individuals. -
Question 72 of 100
72. Question
1 pointsAn increased risk for deep venous thrombosis is associated with which one of the following?
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Explanation:
Oral birth control pills have been associated with an increased incidence of deep venous thrombosis. No association between the other agents and thrombosis has been described. -
Question 73 of 100
73. Question
1 pointsA 26 year old male with manic depression is started on lithium treatment. Which of the following is NOT a potential side effect of the drug?
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Incorrect
Explanation:
The use of lithium in bipolar disorder is contraindicated for individuals with preexisting renal disease, owing to lithium´s renal toxicity In addition, lithium can also cause gastric distress, cardiac conduction aberrancies, hypothyroidism, arid tremor. Seizures are not typically seen as a complication of lithium treatment. -
Question 74 of 100
74. Question
1 pointsHallucinations are most commonly associated with overdose of which one of the following agents?
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Explanation:
LSD is most commonly associated with hallucinations. The other compounds are not. -
Question 75 of 100
75. Question
1 pointsBlood pressure of a 35 year old man is found to be 150/1 20 mm Hg on routine physical examination. Ultrasound shows massively enlarges kidneys with many cysts of varying sizes. What drug class would most directly address his pathology?
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Incorrect
Explanation:
The disease is adult polycystic kidney disease an autosomal dominant disorder. The cysts impair perfusion of glomeruli, which triggers the secretion of renin by the juxtaglomerular complexes. The renin secretion triggers the renin/angiotensin/aldosterone system. ACE (angiotensin-converting enzyme) inhibitors directly interrupt this system by blocking the conversion of angiotensin I to angiotensin II. Calcium channel blockers (e.g., nifedipine, verapamil, Diltiazem) control hypertension by blocking calcium entry into cells, thereby inhibiting vascular smooth muscle contraction. Centrally acting sympatholytics (e.g., clonidine) lower blood pressure by stimulating adrenergic receptors (alpha 2) in the brain, thus reducing sympathetic outflow. Nitrates (e.g., nitroglycerin) release nitric oxide in smooth muscle cells, stimulating guanyiate cyclase. The subsequent increase in cGMP leads to smooth muscle relaxation and vasodilation. Thiazide diuretics (e.g., hydrochlorothiazide) act on the early distal tubule and would not directly address the cause of the hypertension. -
Question 76 of 100
76. Question
1 pointsBelow graph shows plasma cholecystokinin (CCK) concentration after intraduodenal meal perfusion with and without intravenous administration of Drug X. Drug X was also shown to markedly decrease gallbladder contractions. Drug X is also likely to increase which substance?
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Incorrect
Explanation:
Since Drug X enhances plasma CCK levels but blocks one of its major physiologic effects, it must be a CCK receptor antagonist. CCK acts via vagal afferent pathways to stimulate somatostatin inhibition of gastric acid secretion. It the CCK receptors are blocked, gastric acid secretion will increase.
Decreased gallbladder contraction will lower bilirubin levels. Since CCK stimulates pancreatic amylase and lipase secretion, these would be expected to decrease. OCR also stimulates vagal afferents, so it the OCR receptors are blocked, there would be decreased vagal afferent activity. -
Question 77 of 100
77. Question
1 pointsA 58 year old man has nosebleed for the past 2 hours. 5 months ago he received a prosthetic heart valve and is currently taking warfarin (7.5 mg per day) and oral antibiotics. Investigation reveals an INR of 6.4. The patient is most likely taking which antibiotic?
Correct
Incorrect
Explanation:
The patient is most likely experiencing a potentiation of the effects of Warfarin by norfloxacin, which decreases the metabolism of the Warfarin. Warfarin is stereoselectively metabolized by hepatic cytochrome P450 (CYP). Warfarin inhibits the synthesis of vitamin K-dependent coagulation factors II, VII, X and anticoagulant proteins C and S. The increased Warfarin effect produces an increase in the INR. (The target INP for patients with prosthetic heart valves is usually 1.5 to 4, depending on the type of valve.) Although among the choices given norfloxacin is the most likely drug to cause this effect in this patient, the antibiotics most commonly associated with this type of interaction are the macrolides, such as erythromycin, metronidazole, and the sulfonamide antibiotics. Oral doses of penicillins, such as ampicillin, are generally not associated with a potentiation of warfarin´s effect although large IV doses of penicillin may be. Cephalexin is a first generation cephalosporin that can be used in the treatment of acute cystitis. Although this agent is generally not associated with an increased hypoprothrombinemic effect when given with Warfarin, the cephalosporins that have a methyltetrazoiethiol side chain, such as cefazolin, cefmetazole, and cefoperazone, are known to increase warfarin´s therapeutic effect. Nitrofurantoin is a urinary anti-infective agent that does not interact with Warfarin. Phenazopyridine is a urinary tract analgesic that does not interact with Warfarin, although it commonly changes the color of urine to a bright orange red color, which the patient may mistake as blood in the urine. -
Question 78 of 100
78. Question
1 pointsA newlywed 24 year old female is undergoing elective surgery. Her physician decides to place her on preventative anticoagulation therapy with a drug that inhibits the production of clotting factors II, VII, IX, and X. He should first obtain which test result?
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Incorrect
Explanation:
Warfarin is an anticoagulant that interferes with the synthesis of the vitamin K dependent clotting factors (II. VII, IX, X). The antithrombotic effects of this medication are not fully seen until 2to 5 days (mean: 3 to 4 days) after the first dose. It is indicated for the treatment/prevention of a variety of hypercoagulation disorders such as deep venous thrombosis. This agent is contraindicated in pregnancy (FDA Pregnancy Category X) since it can cross the placental barrier and cause fetal hemorrhages, embryopathy, optic atrophy, and brain abnormalities. Hence, this agent should never be given to pregnant women, or to women who are attempting to conceive. Antinuclear antibodies are associated with autoimmune diseases such as systemic lupus erythematosus, scleroderma, Sjogren syndrome, and inflammatory´ myopathies. The test would be of no value in this case. A barium swallow is not indicated prior to the administration of warfarin.
Esophageal manometry is used to evaluate the competency of the lower esophageal sphincter, and to assess esophageal motor activity. The osmotic fragility test is performed by placing erythrocytes into a low-salt solution. An increased susceptibility to osmotic lysis is found in hereditary spherocytosis. -
Question 79 of 100
79. Question
1 pointsA 73 year old man had a 9-pound weight loss over the past few weeks. He is currently undergoing treatment for small cell carcinoma. According to him even though his wife is preparing his favorite meals, he is not hungry. Which would be the best medication to improve his appetite?
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Incorrect
Explanation:
One of the most common side effects of any antineoplastic therapy is weight loss secondary to decreased appetite and/or nausea and vomiting. Furthermore, weight loss due to decreased food intake tends to occur more frequently in elderly patients receiving antineoplastic therapy. One medication that has consistently helped to increase appetite in such patients is megestrol acetate. This agent is a progestational hormone with antineoplastic properties used in the treatment of advanced carcinoma of the breast and endometrium. Megestrol, when given in relatively high doses, can substantially increase the appetite in most individual, even those with advanced cancer. Amitriptyline is a tricyclic antidepressant used in the treatment of depression. There is nothing mentioned in the case study to suggest that the patient is clinically depressed; hence, this agent would provide no benefit. Methotrexate is an antimetabolite and folic acid antagonist; commonly used in various neoplastic disorders and in the treatment of rheumatoid arthritis. Since nausea, vomiting, and ulcerative stomatitis are common side effects of this medication, use in this patient would not be recommended. Neostigmine is a carbamylating acetylcholinesterase inhibitor that; would not increase appetite. Prochlorperazine is a phenothiazine derivative used primarily to control severe nausea and vomiting. This patient is not experiencing nausea. Furthermore, this agent does not possess appetite stimulating properties. -
Question 80 of 100
80. Question
1 pointsA 23 year old marine was bitten by female phlebotomine sandfly on his hand 45 days earlier near Persian Gulf. The bite progressed to an ulcerated lesion that would not heal. He also has chronic fatigue, weakness, dysphagia, and dyspnea. Which medication should he be prescribed for his condition?
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Explanation:
In this question, you must make the correct diagnosis, then determine the most optimal therapy. The patient is suffering from viscerale leishmaniasis. The disease is associated with fever, which can be persistent, of a long duration (weeks), and may cycle irregularly. Night sweats, fatigue weakness, anorexia, weight loss scaly, or gray, dark, ashen skin, and thinning of the hair also occur. Skin manifestations include erythematous macules or papules, and skin ulcers, which form at the site of original lesion and heal slowly (over a period of months). Ulcers of the mouth, tongue, gums, lips, nose, and nasal septum may also occur. Dysphagia with esophageal involvement and dyspnea can also occur. Death, often within 2 years in untreated individuals, usually results from complications (such as other infections) rather than from the disease itself. Cases of leishmaniasis have been reported on all continents except Australia. In the Americas, Leishmania can be found in Mexico and south into the South American continent. Leishmaniasis has been reported among some military personnel returning from the Persian Gulf. Antimony containing compounds are the principal medications used to treat leishmaniasis, and include sodium stibogluconate and meglumine antimonate. Other medications that may be used include pentamidine and amphotericin B. Acyclovir is an antiviral agent indicated for the treatment of herpes virus infections. Ganciclovir is used in the treatment of cytomegalovirus infections. Isoniazid and rifampin are the drugs of choice for the treatment of classical tuberculosis. Loracarbef is second generation cephalosporin indicated for variety of gram- negative and gram-positive bacteria. -
Question 81 of 100
81. Question
1 pointsA worker is brought in respiratory distress. He had been spraying an insecticide in the fields, and today he began to feel sweaty and dizzy. When brought to the hospital he was drooling, gasping, and becoming agitated. His symptoms are due to the action of the insecticide on which one of the following?
Correct
Incorrect
Explanation:
Organophosphate insecticides such as parathion function as acetylcholinesterase inhibitors, producing increased acetylcholine levels at all cholinergic synapses. Although both muscarinic and nicotinic receptors are stimulated, the muscarinic effects are usually identified first. Treatment with atropine is generally indicated with organophosphate intoxication. Muscarinic and nicotinic receptors are not directly affected by organophosphates. The drug´s actions are completely indirect; increased stimulation is due to the lengthened half life of acetylcholine at the synapse. The neuronal lipid bilayer is disturbed by inhalational anesthetic drugs. Although the mechanism of action is poorly understood, it is believed to be a consequence of altered neuronal transmission and ion channel dysfunction. Nerve conduction is blocked when local anesthetics bind to and inactivate voltage gated sodium channels. -
Question 82 of 100
82. Question
1 pointsA 72 year old woman with shortness of breath is diagnosed with congestive heart failure. One of the drugs she is given is spironolactone. The drug acts at which of the following areas of the nephron indicated in the diagram below?
Correct
Incorrect
Explanation:
Potassium sparing diuretics act as antagonists at the intracellular aldosterone receptor located in the collecting tubule. By doing so, they decrease the expression of the genes for sodium channels and the Na+/K+ ATPase.
No known diuretics act at the glomerulus. Carbonic anhydrase inhibitors, such as acetazolamide, inhibit sodium bicarbonate reabsorption from the proximal tubule.
Ethacrynic acid is a loop diuretic that acts by inhibiting the Na+/K+/2C1- transporter located in the ascending loop of Henle. Thiazide diuretics inhibit the Na+/Cl- transporter in the early segment of the distal convoluted tubule. -
Question 83 of 100
83. Question
1 pointsA 59 year old female has a sudden onset of orthopnea, paroxysmal nocturnal dyspnea, and nocturia. Exam reveals tachycardia and both pulmonary rales and a third sound (S3) are noted. If she is receiving therapy for breast cancer, which drug did she most likely receive?
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Explanation:
Dilated (congestive) cardiomyopathy results in a diminution in the contractile function of the left, right, or even both ventricles of the heart. The loss of heart muscle function frequently results in the development of congestive heart failure. This patient is presenting with classic signs and symptoms of congestive cardiomyopathy/congestive heart failure; orthopnea, paroxysmal nocturnal dyspnea, nocturia, tachycardia, pulmonary rales, and a third heart sound (S3) are noted. The anthracycline antibiotics doxorubicin and daunomycin both are commonly associated with the development of congestive cardiomyopathy; however, the incidence is much higher with doxorubicin therapy. Doxorubicin is an antibiotic antineoplastic agent commonly used in the treatment of sarcomas, multiple myeloma, malignant lymphoma, acute leukemias, and ovarian, breast, testicular, gastric, bladder, and throat cancer. Bleomycin is classified as an anticancer antibiotic and is one of the few chemotherapeutic agents that does not cause bone marrow suppression. Bleomycin, along with busulfan, carmustine (BCNU), and methotrexate, are commonly associated with the development of pulmonary toxicity´. Bleomycin is indicated for the treatment of squamous cell carcinomas of the head, neck, penis, cervix, and vulva, as well as several types of lymphomas. Carmustine is an alkylating agent commonly used in the treatment of Hodgkin´s disease and other lymphomas. The most notable side effects of this agent are “delayed” myelosuppression and pulmonary toxicity. Cisplatin is an alkylating agent indicated for the treatment of metastatic testicular and ovarian tumors in combination with other agents. This agent can cause severe bone marrow suppression as well as profound renal toxicity. Methotrexate is an antimetabolite and folic acid antagonist commonly used in various neoplastic disorders, such as pediatric acute lymphocytic leukemia, Burkitt´s lymphoma, non-Hodgkin´s lymphoma, breast, head, neck, and small cell lung cancer. The most common side effects seen with this agent are mucositis, gastrointestinal ulcer, hepatotoxicity, bone marrow suppression, and pulmonary toxicity. -
Question 84 of 100
84. Question
1 pointsA patient develops severe hypocalcemia and hyperphosphatemia after thyroidectomy resulting in carpopedal spasms, muscle and abdominal cramps, and tingling of his lips and hands. Tapping his face in front of the ear elicits tetany of his facial muscles. Which drug would likely ameliorate his signs and symptoms?
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Incorrect
Explanation:
The patient is presenting with signs and symptoms highly suggestive of hypoparathyroidism. This condition occurs most frequently after thyroidectomy or the removal of a parathyroid adenoma. Hypoparathyroidism is characterized by severe hypocalcemia and hyperphosphatemia, resulting in tetany, carpopedal spasms, muscle and abdominal cramps, and tingling of the lips and hands. A positive Chvostek sign (tapping the Lace in front of the ear elicits tetany) and Trousseau sign (abnormal muscular contractions elicited by applying a blood pressure cuff) will often be noted. Since the blood calcium levels are often very low, either calcium gluconate or vitamin D preparations should be administered to correct the condition. Vitamin D preparations, such as ergocalciferol (Vitamin D2), elevate calcium levels, and decrease phosphate levels. Bumetanide is a loop diuretic used to treat various edematous states. This product is contraindicated in patients with hypoparathyroidism because it decreases blood calcium levels, which will worsen the condition. Levothyroxine is used as replacement therapy for diminished or absent thyroid function. Although patients with hypoparathyroidism may also be hypothyroid, the use of levothyroxine will not correct the hypocalcemia and hyperphosphatemia. Niacin is used to treat pellagra and as an adjuvant agent to treat hyperlipidemia. The use of pamidronate in a patient with hypoparathyroidism is contraindicated since this agent is used to treat hypercalcemia and would subsequently worsen the patient´s hypocalcemia. -
Question 85 of 100
85. Question
1 pointsA 63 year old male presents complaining of difficulty urinating and “dribbling” at the end of urination. He is diagnosed with benign prostatic hyperplasia. Which drug would be most appropriate for treating this man´s condition?
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Incorrect
Explanation:
Finasteride, an inhibitor of 5-alpha-reductase, prevents the conversion of testosterone to dihydrotestosterone (DHT). Because dihydrotestosterone is essential for the normal growth and development of the prostate gland, finasteride is an effective treatment for benign prostatic hyperplasia, which is a DHT-dependent process. (A better choice would have been an alpha blocking agent, but none was available as an answer.) Leuprolide is a gonadotropin releasing hormone (GnRH) analog. It is used at times for the palliative treatment of advanced prostate carcinoma. Mifepristone, also known as RU486, is a competitive inhibitor at progesterone receptors. It has been used as a contraceptive or as an abortifacient to terminate early pregnancy. Pergolide, a synthetic ergoline, is a direct agonist at dopamine D1 and D2 receptors. It has been used in association with levodopa in the therapy of Parkinson disease. Tamoxifen is a competitive antagonist at estrogen receptors located in the breast. This drug is used in reducing the recurrence of estrogen receptor positive breast cancer, particularly in postmenopausal women. -
Question 86 of 100
86. Question
1 pointsA 34 year old male receiving chemotherapy for testicular carcinoma develops signs of renal tubular damage. Which medication is most likely responsible for this nephrotoxicity?
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Incorrect
Explanation:
Cisplatin is an antineoplastic drug used in the treatment of carcinoma of the testes (along with bleomycin and vinblastine), ovaries, bladder, and lung (especially small cell). Along with the typical side effects of nausea, vomiting, and bone marrow suppression, cisplatin is notable for its dose-limiting nephrotoxicity and ototoxicity. Bleomycin is very effective against testicular tumors and is used in combination with cisplatin and vinblastine. The most noteworthy side effect of bleomycin is pulmonary toxicity that can progress to pulmonary fibrosis. Cyclophosphamide is a commonly used chemotherapeutic that is effective in the treatment of lymphomas, multiple myeloma, lymphoblastic leukemias, carcinomas (e.g., breast, ovary, lung, cervix), mycosis fungoides, and neuroblastoma. Note that it is not used in the treatment of testicular cancer. In addition, its most notable side effect is hemorrhagic cystitis (not nephrotoxicity).
Vinblastine is used for the treatment of testicular tumors. It is also used for Hodgkin disease, lymphomas, and Kaposi sarcoma. Vinblastine is notable for its dose-limiting bone marrow suppression. Vincristine, also known as Oncovin, is used as part of the MOPP (mechlorethamine, Oncovin, procarbazine and prednisone) regimen for the treatment of Hodgkin disease. It is also used in the treatment of acute lymphocytic leukemia (ALL), sarcoma, CNS tumors, and Wilms tumor. Vincristine´s noteworthy side effect is its dose limiting neurotoxicity. -
Question 87 of 100
87. Question
1 pointsThe following are pharmacokinetic parameters of a new antibiotic that were previously determined:
Clearance = 100 mL/min
Volume of distribution (Vd) = 50 L
Half-life = 3 hours
Assuming that the drug is being administered intravenously, what loading dose (LD) should be given to quickly obtain a plasma concentration of 10 mg/L?Correct
Incorrect
Explanation:
The object of a loading dose (LD) is to “load up” the volume of distribution in order to quickly achieve the desired. plasma concentration. You can calculate it by the following equation:
LD=Vd x Cp
(Vd = volume of distribution; Cp = plasma concentration)
In this case, LD = (50 L) x (10 mg/L) = 500 mg -
Question 88 of 100
88. Question
1 pointsTeacher of a 6 year old boy noticed that the child has become inattentive. Her son frequently stops what he is doing and “stares blankly into space” before resuming his activities. EEG reveals a 3/second spike and slow wave pattern of discharges. Which medicine would most effectively treat his disorder?
Correct
Incorrect
Explanation:
The child has absence seizures. The age of onset is typically from 3 to 7 years; seizures may continue into adolescence, but generally subside before adulthood. These seizures have been known to occur up to 100 times a day. Ethosuximide is indicated for this type (but no other type) of seizure. Other drugs used in the treatment of absence seizures are valproic acid, clonazepam, and lamotrigine. Carbamazepine is used in the treatment of tonic clonic (grand mal) and partial (focal) seizures. Diazepam has long been the drug of choice for status epilepticus. Recently, lorazepam (a shorter acting benzodiazepine) has also been accepted as a drug for this condition. IV phenytoin is used if prolonged therapy is required. Phenobarbital has also been used, especially in children. If the status epilepticus is very severe and does not respond to these measures general anesthesia may be used. Methylphenidate (Ritalin) is a stimulant used to treat children with attention deficit disorder. This child has no history of hyperactivity, and the underlying cause of his “inattentiveness” is his seizure disorder. Phenytoin is effective in all seizure types except for the one in this question (absence). Note that phenytoin has some idiosyncratic side effects, including hirsutism and gingival hyperplasia. -
Question 89 of 100
89. Question
1 pointsA 30 year old newlywed has a sharp, burning epigastric pain. She recently started NSAID therapy to relieve pain caused by rheumatoid arthritis. Misoprostol is recommended to relieve her gastric distress. Before prescribing this drug, the physician should first obtain the result of which test?
Correct
Incorrect
Explanation:
Misoprostol, a methyl analog of prostaglandin E1, is approved for the prevention of ulcers caused by the administration of NSAIDs. Because this drug is a potential abortifacient, it should not be given to pregnant women, or to women who are attempting to conceive. Antinuclear antibodies are associated with autoimmune diseases, such as systemic lupus erythematosus, scleroderma, Sjögren syndrome, and inflammatory myopathies. The test would be of no value in this case. A barium swallow is not indicated prior to the administration of misoprostol. Esophageal manometry is used to evaluate the competency of the lower esophageal sphincter and to assess esophageal motor activity. The osmotic fragility test is performed by placing erythrocytes into a low salt solution. An increased susceptibility to osmotic lysis is found in hereditary spherocytosis. -
Question 90 of 100
90. Question
1 pointsA 48-year-old female with rheumatoid arthritis has the following full blood count results:
Haemoglobin 11.4 g/dL
Platelets 470 x103/L
White Cell Count 9.0 x 103/L
MCV 102 fL
Which drug is she likely to be taking?Correct
Incorrect
Explanation:
Leflunomide is associated rarely with anaemia, thrombocytopaenia and eosinophilia. Ciclosporin may be associated with a mild anaemia.
Methotrexate may be associated with haematopoietic suppression, leading to profound and sometimes sudden leucopenia and thombocytopaenia.
Methotrexate may lead to macrocytosis as a result of B12 or folate deficiency.
Myocrisin may also rarely lead to blood disorders, pancytopaenia and leucopenia. The elevated platelet count here probably relates to the rheumatoid arthritis itself. -
Question 91 of 100
91. Question
1 pointsA 59-year-old male presents with painful breast tissue. Six weeks previously he was treated for some cardiovascular cause and had a number of drugs commenced. Which one of the following drugs may have caused this problem?
Correct
Incorrect
Explanation:
Digoxin may cause gynaecomastia but usually only on prolonged use Spironolactone is well known to cause gynaecomastia due to its well described anti-androgen effects. -
Question 92 of 100
92. Question
1 pointsA 56-year-old chronic hypertensive male is being treated with Lithium for a bipolar disorder. He was also taking anti-hypertensive therapy and recently a new agent was added to his current therapy. Five days later he presents with Lithium toxicity. What drug is responsible?
Correct
Incorrect
Explanation:
The precipitation of Lithium toxicity by diuretics is well appreciated. Yet ACE inhibitors and Angiotensin Antagonists are also capable of precipitation Lithium toxicity through reduced Lithium clearance. Other tetracycline, phenytoin and ciclosporin. -
Question 93 of 100
93. Question
1 pointsIn which of the following would the first drug be associated with increased pharmacological action of the second drug?
Correct
Incorrect
Explanation:
Erthromycin would inhibit the metabolism of Theophylline. Ranitidine unlike cimetidine is not enzyme inhibitors. Phenytoin would speed up metabolism of ethinyl-oestradiol making the pill less effective.
Rifampicin is a well-recognized enzyme inducer. -
Question 94 of 100
94. Question
1 pointsA patient is taking St John´s wort for depressive symptoms.
Which of the following drugs would be contraindicated to use in this patient?Correct
Incorrect
Explanation:
St John´ wort is an herbal medicine used in the treatment of depression. St. John´s wort contains substances that appear to have an antidepressant effect. Although the exact causes of this potential interaction are not understood, the antidepressant effects of drugs like phenelzine may be increased, decreased, or erratic when taken at the same time that St. John´s wort is being used. In general, it is not advisable to use St. John´s wort or any other herbal supplement while one is taking phenelzine. -
Question 95 of 100
95. Question
1 pointsA 44 year old male is diagnosed by his physician as having major depressive disorder. The patient tells his physician that he is extremely concerned about his sexual performance, as he is worried that he is getting older and that he is having some marital difficulties with his wife. Which antidepressant would be the best choice for initial treatment?
Correct
Incorrect
Explanation:
Bupropion is the antidepressant of the choices listed that has the fewest adverse sexual side effects. Selective serotonin reuptake inhibitors, such as fluoxetine, paroxetine, and sertraline are all known to be associated with erectile and orgasmic disturbances, such as delayed ejaculation and anorgasmia. Because imipramine also has effect on the serotonin levels in the brain, it too has sexual side effects, although to a somewhat lesser degree than the SSRIs. -
Question 96 of 100
96. Question
1 pointsIn a severely distressed patient with panic disorder, the rapid relief of symptoms would be best provided by which one of the following?
Correct
Incorrect
Explanation:
All the agents listed are effective in the management of panic disorder. However only alprazolam has an onset of action measured in hours instead of weeks, making it the most appropriate choice for managing acutely distressed patients, Because of the difficulty in discontinuing benzodiazepines, their most common use is to stabilize severe initial symptoms until another treatment becomes effective. -
Question 97 of 100
97. Question
1 pointsAll of the following are common side effects of SSRIs, except
Correct
Incorrect
Explanation:
The most common side effects when taking SSRIs include headache, nausea, somnolence (drowsiness), weight/appetite fluctuations, changes in sexual behavior and increased feelings of anxiety or depression. These side effects are mostly present during the initial 1-4 weeks while the body adapts to the drug.
It is well documented that SSRIs can cause various sexual dysfunctions such as anorgasmia (inability to reach orgasm), diminished libido (sex drive) and erectile dysfunction or difficult/premature ejaculation in men. Such side effects have been found present in between 41% and 83% of patients responding to physician inquiry. These side effects occasionally disappear spontaneously without discontinuing use of the drug, and in most cases resolve themselves after stopping taking the SSRI. -
Question 98 of 100
98. Question
1 pointsA 25 year old nurse is concerned that she is losing her mind. She has been preoccupied with contamination on her ward for the past 6 months. She has not been touching any doorknobs washing her hands excessively. The appropriate therapy for her disorder is
Correct
Incorrect
Explanation:
Obsessive-compulsive disorder (OCD) is characterized by anxiety-provoking ideas, images, or impulses (obsessions) and by urges (compulsions) to do something that will lessen that anxiety. The cause is unknown. Diagnosis is based on history. Treatment consists of psychotherapy, drug therapy, or, especially in severe cases, both. Many experts believe that combining psychotherapy and drug therapy is best, especially for severe cases. Medications used are selective serotonin reuptake inhibitors (eg fluoxetine) and clomipramine. -
Question 99 of 100
99. Question
1 pointsThe treatment for methicillin-resistant Staphylococcus aureus is
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Incorrect
Explanation:
Vancomycin is the treatment of choice for methicillin-resistant Staphylococcus aureus. The other antibiotics are ineffective. -
Question 100 of 100
100. Question
1 pointsWhich of the following drugs is usually considered safe for ingestion by an individual with variegate porphyria?
Correct
Incorrect
Explanation:
Aspirin is safe in variegate porphyria, as it is in acute intermittent porphyria. The other agents all can cause exacerbations of these conditions.