B3 AccessMed

Question 0

Characteristics of phase I depolarizing neuromuscular blockade due to succinylcholine include

Answer 0

Ans:Sustained tension during a period of tetanic stimulation

Phase I depolarizing blockade caused by succinylcholine is not associated with antagonism at muscarinic receptors, nor is it reversible with cholinesterase inhibitors. Muscle fasciculations occur at the start of the action of succinylcholine.

Question 1

Which statement concerning the adverse effects of antipsychotic drugs is accurate?

Answer 1

Ans:Acute dystonic reactions occur very infrequently with olanzapine

Olanzapine has minimal dopamine receptor-blocking action and is unlikely to cause acute dystonias. Muscarinic blockers such as atropine exacerbate tardive dyskinesias. Akathisias (uncontrollable restlessness) resulting from antipsychotic drugs may be relieved by a reduction in dosage. Retinal pigmentation may occur with thioridazine, not clozapine.

Question 2

Concerning hypotheses for the pathophysiologic basis of schizophrenia, which statement is accurate?

Answer 2

Ans: Drug-induced psychosis can occur without activation of brain dopamine receptors

Although most older antipsychotic drugs block D2 receptors, this action is not a requirement for antipsychotic action. Aripiprazole, clozapine, and most newer second-generation drugs have a very low affinity for such receptors, but a high affinity for serotonin 5-HT2 receptors. There are no reports of changed levels of serotonin in the brains of schizophrenics. The CNS effects of phencyclidine (PCP) closely parallel an acute schizophrenic episode, but PCP has no actions on brain dopamine receptors. Dopamine receptor blockers cause extrapyramidal dysfunction.

Question 3

Concerning the proposed mechanisms of action of antidepressant drugs, which statement is accurate?

Answer 3

Ans: Nefazodone blocks 5-HT receptors in the CNS

The mechanism of action of bupropion is unknown, but the drug does not inhibit either NE or 5-HT transporters. Levels of NE and 5-HT metabolites in the cerebrospinal fluid of depressed patients before drug treatment are not higher than normal. Downregulation of adrenoceptors appears to be a common feature of chronic treatment of depression with tricyclic drugs such as amitriptyline. Selegiline is a selective inhibitor of MAO-B, the enzyme form that metabolizes dopamine (see Chapter 28). Nefazodone is a highly selective antagonist at the 5-HT2 receptor subtype.

Question 4

One effect that theophylline, nitroglycerin, isoproterenol, and histamine have in common is

Answer 4

Ans: Tachycardia

Theophylline does not ordinarily cause headache or postural hypotension. Nitroglycerin does not cause direct cardiac stimulation but does evoke a compensatory sympathetic reflex. Histamine does not cause bronchodilation.

Question 5

A 23-year-old woman is using an albuterol inhaler for frequent acute episodes of asthma and complains of symptoms that she ascribes to the albuterol. Which of the following is not a recognized action of albuterol?

Answer 5

Ans: Diuretic effect

Albuterol is a 2-selective receptor agonist, but in moderate to high doses it induces 1 cardiac effects as well as 2-mediated smooth and skeletal muscle effects. It does not cause diuresis.

Question 6

A 51-year-old patient with parkinsonism is being maintained on levodopa-carbidopa with adjunctive use of low doses of entacapone, but continues to have off-periods of akinesia. The most appropriate drug to “rescue” the patient but that will only provide temporary relief is

Answer 6

Ans: Apomorphine

Apomorphine, via subcutaneous injection, is used for temporary relief of off-periods of akinesia (“rescue”) in parkinsonian patients on dopaminergic drug therapy. Pretreatment with the antiemetic trimethobenzamide for 3 days is essential to prevent severe nausea

Question 7

Your 37-year-old patient has been diagnosed with a rare metastatic carcinoid tumor. This neoplasm is releasing serotonin, bradykinin, and several unknown peptides. The effects of serotonin in this patient are most likely to include which one of the following?

Answer 7

Ans: Episodes of bronchospasm

Serotonin causes bronchospasm, but the other effects listed are not observed. Carcinoid is associated with diarrhea and hypertension.

Question 8

A 36-year-old woman presents with symptoms of major depression that are unrelated to a general medical condition, bereavement, or substance abuse. She is not currently taking any prescription or over-the-counter medications. Drug treatment is to be initiated with paroxetine. In your information to the patient, you would tell her that

Answer 8

Ans: All the Above

• It is preferable that she does not take the drug in the evening
• Muscle cramps and twitches can sometimes occur
• She should tell you if she anticipates using other prescription drugs
• The antidepressant effects of paroxetine may take 2 weeks or more to become effective

All the statements are appropriate regarding the initiation of treatment with fluoxetine or other SSRI in a depressed patient. The SSRIs have CNS-stimulating effects and may cause agitation, anxiety, “the jitters,” and insomnia, especially early in treatment. Consequently, the evening is not the best time to take SSRI drugs.

Question 9

Bradykinesia has made drug treatment necessary in a 60-year-old male patient with Parkinson’s disease, and therapy is to be initiated with levodopa.

Regarding the anticipated actions of levodopa, the patient would not be informed that

Answer 9

Ans: A netlike reddish to blue discoloration of the skin is a possible side effect.

In prescribing levodopa, the patient should be informed about adverse effects, including gastrointestinal distress, postural hypotension, and dyskinesias. It is reasonable to advise the patient that therapeutic benefits cannot be expected to continue indefinitely. Livedo reticularis (a netlike rash) is an adverse effect of treatment with amantadine.

Question 10

A 16-year-old patient is in the emergency department receiving nasal oxygen. She has a heart rate of 125 bpm, a respiratory rate of 40 breaths/min, and a peak expiratory flow

Answer 10

Ans: Blockade of histamine receptors

Histamine does not appear to play a significant role in asthma, and antihistaminic drugs, even in high doses, are of little or no value. Antigen avoidance is well established. Blockade of leukotriene receptors with montelukast; inhibition of phospholipase with corticosteroids; and inhibition of mediator release with the IgE antibody are also useful.

Question 11

Trifluoperazine was prescribed for a young male patient diagnosed as suffering from schizophrenia. He complains about the side effects of his medication. Which of the following is not likely to be on his list?

Answer 11

Ans: Excessive salivation

Phenothiazines such as trifluoperazine cause sedation and are antagonists at muscarinic and adrenoceptors. Postural hypotension, blurring of vision, and dry mouth are common autonomic adverse effects, as is constipation. Effects on the male libido may result from increased prolactin or from increased peripheral conversion of androgens to estrogens.

Question 12

Which statement concerning the use of lithium in the treatment of bipolar affective disorder is accurate?

Answer 12

Ans: Lithium dosage may need to be decreased in patients taking thiazides

Clinical effects of lithium are slow in onset and may not be apparent before 1 or 2 weeks of daily treatment. High urinary levels of sodium inhibit renal tubular reabsorption of lithium, thus decreasing its plasma levels. Lithium clearance is decreased by distal tubule diuretics (eg, thiazides) because natriuresis stimulates a reflex increase in the proximal tubule reabsorption of both lithium and sodium. Any drug that can cross the blood-brain barrier can cross the placental barrier! Teratogenic risk is low, but use of lithium during pregnancy may contribute to low Apgar score in the neonate.

Question 13

Oral medications are popular for the treatment of asthma in children because young children may have difficulty with the proper use of aerosol inhalers. Which of the following is an orally active inhibitor of leukotriene receptors?

Answer 13

Ans: Montelukast

Zileuton is an inhibitor of the lipoxygenase enzyme involved in the synthesis of leukotrienes. Montelukast and zafirlukast are leukotriene antagonists at the leukotriene receptor.

Question 14

Increased serum levels of which of the following is associated with a decreased risk of atherosclerosis?

Answer 14

Ans: HDL

Increased serum concentrations of LDL and total cholesterol are associated with increased risk of atherosclerosis. High serum concentration of HDL cholesterol is associated with a decrease in the risk of atherosclerotic disease.

Question 15

Bradykinesia has made drug treatment necessary in a 60-year-old male patient with Parkinson’s disease, and therapy is to be initiated with levodopa.

The prescribing physician will (or should) know that levodopa

Answer 15

Ans: Fluctuates in its effectiveness with increasing frequency as treatment continues

Levodopa causes less peripheral toxicity but more CNS or behavioral side effects when its conversion to dopamine is inhibited outside the CNS. The drug is not effective in antagonizing the akinesia, rigidity, and tremor caused by treatment with antipsychotic agents. Levodopa is a precursor of melanin and may activate malignant melanoma. Use of levodopa is not associated with pulmonary dysfunction.

Question 16

A 10-year-old child has severe asthma and was hospitalized 5 times between the ages of 7 and 9. He is now receiving outpatient medications that have greatly reduced the frequency of severe attacks. Which of the following is most likely to have adverse effects when used daily over long periods for severe asthma?

Answer 16

Ans: Prednisone by mouth

If oral corticosteroids must be used, alternate-day therapy is preferred because it interferes less with normal growth in children.

Question 17

A 35-year-old woman appears to have familial combined hyperlipidemia. Her serum concentrations of total cholesterol, LDL cholesterol, and triglyceride are elevated. Her serum concentration of HDL cholesterol is somewhat reduced.

Which of the following drugs is most likely to increase this patient’s triglyceride and VLDL cholesterol concentrations when used as monotherapy?

Answer 17

Ans: Cholestyramine

In some patients with familial combined hyperlipidemia and elevated VLDL, the resins increase VLDL and triglyceride concentrations even though they also lower LDL cholesterol.

Question 18

A 16-year-old patient is in the emergency department receiving nasal oxygen. She has a heart rate of 125 bpm, a respiratory rate of 40 breaths/min, and a peak expiratory flow

Answer 18

Ans: Prednisone

Although extremely important in severe chronic asthma and status asthmaticus, corticosteroids do not have a demonstrable direct bronchodilator action.

Question 19

A patient underwent a surgical procedure of 2 h. Anesthesia was provided by isoflurane, supplemented by intravenous midazolam and a nondepolarizing muscle relaxant. At the end of the procedure, a low dose of glycopyrrolate was administered followed by pyridostigmine.

The main reason for administering the muscarinic receptor antagonist was to

Answer 19

Ans: Prevent activation of cardiac muscarinic receptors

Acetylcholinesterase inhibitors used for reversing the effects of nondepolarizing muscle relaxants cause increases in ACh at all sites where it acts as a neurotransmitter. To offset the resulting side effects, including bradycardia, a muscarinic blocking agent is used concomitantly. Although atropine is effective, glycopyrollate is usually preferred because it lacks CNS effects.

Question 20

A 9-year-old child is having learning difficulties at school. He has brief lapses of awareness with eyelid fluttering that occur every 5–10 min. Electroencephalogram (EEG) studies reveal brief 3-Hz spike and wave discharges appearing synchronously in all leads. Which drug would be effective in this child without the disadvantages of excessive sedation or tolerance development?

Answer 20

Ans: Ethosuximide

This child suffers from absence seizures, and 2 of the drugs listed are effective in this seizure disorder. Clonazepam is effective but exerts troublesome CNS-depressant effects, and tolerance develops with chronic use. Ethosuximide is not excessively sedating, and tolerance does not develop to its antiseizure activity. Valproic acid (not listed) is also used in absence seizures.

Question 21

Which statement about ropinirole is accurate?

Answer 21

Ans: Warfarin may enhance the actions of ropinirole

Ropinirole is a dopamine D2 receptor activator and does not require bioactivation. Confusion, delusions, and hallucinations occur more frequently with dopamine receptor activators than with levodopa. The use of dopaminergic agents in combination with antimuscarinic drugs is common in the treatment of parkinsonism. Ropinirole is metabolized by hepatic CYP1A2, and its plasma levels may be increased by other substrates of this enzyme including caffeine and warfarin.

Question 22

A 34-year-old male patient who was prescribed citalopram for depression has decided he wants to stop taking the drug. When questioned, he said that it was affecting his sexual performance. You ascertain that he is also trying to overcome his dependency on tobacco products. If you decide to reinstitute drug therapy in this patient, the best choice would be

Answer 22

Ans: Bupropion

The SSRIs and venlafaxine (an SNRI) can cause sexual dysfunction with decreased libido, erectile dysfunction, and anorgasmia. TCAs may also decrease libido or prevent ejaculation. Bupropion is the least likely antidepressant to affect sexual performance. The drug is also purportedly useful in withdrawal from nicotine dependence, which could be helpful in this patient.

Question 23

Which statement concerning the barbiturates is accurate?

Answer 23

Ans: Alkalinization of the urine accelerates the elimination of phenobarbital

Withdrawal symptoms from use of the shorter-acting barbiturate secobarbital are more severe than with phenobarbital. The dose-response curve for benzodiazepines is flatter than that for barbiturates. Induction of liver drug-metabolizing enzymes occurs with barbiturates and may lead to decreases in half-life of other drugs. Flumazenil is an antagonist at BZ receptors and is used to reverse CNS depressant effects of benzodiazepines. As a weak acid (pKa, 7), phenobarbital will be more ionized (nonprotonated) in the urine at alkaline pH and less reabsorbed in the renal tubule.

Question 24

A 57-year-old man has severe pulmonary hypertension and right ventricular hypertrophy. Which of the following agents causes vasodilation and may be useful in pulmonary hypertension?

Answer 24

Ans: Prostacyclin Prostacyclin (PGI2) is a very potent vasodilator. All the other choices in the list are vasoconstrictors.

Question 25

Regarding the clinical use of antidepressant drugs, which statement is accurate?

Answer 25

Ans: When selecting an appropriate drug for treatment of depression, the history of patient response to specific drugs is a valuable guide No antidepressant has been shown to increase hepatic drug metabolism. MAO inhibitors (not TCAs), though now used infrequently, are the drugs most likely to be effective in depression with attendant anxiety, phobic features and hypochondriasis. SSRIs are usually associated with weight loss, at least during the first 6 months of treatment. There is no evidence that any SSRI is more effective than another, or more effective overall than a tricyclic drug, in treatment of major depressive disorder.

Question 26

Which of the following best describes the mechanism of action of benzodiazepines?

Answer 26

Ans: Increase frequency of opening of chloride ion channels coupled to GABAA receptors Benzodiazepines exert most of their CNS effects by increasing the inhibitory effects of GABA, interacting with components of the GABA-A receptor-chloride ion channel macromolecular complex to increase the frequency of chloride ion channel opening. Benzodiazepines do not affect GABA metabolism or release, and they are not GABA receptor agonists because they do not interact directly with the binding site for GABA.

Question 27

A 19-year-old woman complains of severe dysmenorrhea. A uterine stimulant derived from membrane lipid in the endometrium is

Answer 27

Ans: Prostaglandin PGE2 Although serotonin and, in some species, histamine may cause uterine stimulation, these substances are not derived from membrane lipid. Similarly, oxytocin causes uterine contraction, but it is a peptide hormone secreted by the posterior pituitary. Prostacyclin relaxes the uterus

Question 28

A 43-year-old very overweight man complains of not sleeping well and feeling tired during the day. He tells his physician that his wife is the cause of the problem because she wakes him up several times during the night because of his loud snores. This appears to be a breathing-related sleep disorder, so you should probably write a prescription for

Answer 28

Ans: None of the above Benzodiazepines and barbiturates are contraindicated in breathing-related sleep disorders because they further compromise ventilation. In obstructive sleep apnea (pickwickian syndrome), obesity is a major risk factor. Buspirone is a selective anxiolytic not a hypnotic. The best prescription you can give this patient is to lose weight.

Question 29

A patient with parkinsonism is being treated with levodopa. He suffers from irregular, involuntary muscle jerks that affect the proximal muscles of the limbs. Which of the following statements about these symptoms is accurate?

Answer 29

Ans: Other drugs that activate dopamine receptors can exacerbate dyskinesias in a patient taking levodopa The form and severity of dyskinesias resulting from levodopa may vary widely in individual patients. Dyskinesias occur in up to 80% of patients receiving levodopa for long periods. With continued treatment, dyskinesias may develop at a dose of levodopa that was previously well tolerated. Muscarinic receptor blockers do not prevent their occurrence. They occur more commonly in patients treated with levodopa in combination with carbidopa or with other dopamine receptor agonists.

Question 30

Mr Green is a 60-year-old former smoker with cardiac disease and severe chronic obstructive pulmonary disease (COPD) associated with frequent episodes of bronchospasm. Which of the following is a bronchodilator useful in COPD and least likely to cause cardiac arrhythmia?

Answer 30

Ans: Ipratropium Ipratropium is the bronchodilator that is most likely to be useful in COPD without causing arrhythmias. Tiotropium is similar.

Question 31

A 23-year-old woman suffers from recurrent episodes of angioneurotic edema with release of histamine and other mediators. Which of the following drugs is the most effective physiologic antagonist of histamine in smooth muscle?

Answer 31

Ans: Epinephrine The smooth muscle effects of histamine are mediated mainly by H1 receptors. Cetirizine is a pharmacologic antagonist of histamine. Granisetron is a 5-HT3 antagonist. Sumatriptan is a 5-HT1D agonist. Ranitidine is a histamine antagonist but blocks the H2 receptor in the stomach and the heart, not H1 receptors in smooth muscle. Epinephrine has a physiologic antagonist action that reverses histamine's effects on smooth muscle.

Question 32

Haloperidol is not an appropriate drug for management of

Answer 32

Ans: The amenorrhea-galactorrhea syndrome In addition to its use in schizophrenia and acute mania, haloperidol has been used in the management of intoxication due to phencyclidine (PCP) and in Tourette's syndrome. Hyperprolactinemia and the amenorrhea-galactorrhea syndrome may occur as adverse effects during treatment with antipsychotic drugs, especially those like haloperidol that strongly antagonize dopamine receptors in the tuberoinfundibular tract.

Question 33

A patient underwent a surgical procedure of 2 h. Anesthesia was provided by isoflurane, supplemented by intravenous midazolam and a nondepolarizing muscle relaxant. At the end of the procedure, a low dose of glycopyrrolate was administered followed by pyridostigmine. A muscarinic receptor antagonist would probably not be needed for reversal of the skeletal muscle relaxant actions of a nondepolarizing drug if the agent used was

Answer 33

Ans: Pancuronium One of the distinctive characteristics of pancuronium is that it can block muscarinic receptors, especially those in the heart. It has sometimes caused tachycardia and hypertension and may cause dysrhythmias in predisposed individuals.

Question 34

A 24-year-old stockbroker has developed a "nervous disposition." He is easily startled, worries about inconsequential matters, and sometimes complains of stomach cramps. At night he grinds his teeth in his sleep. There is no history of drug abuse. Diagnosed as suffering from generalized anxiety disorder, he is prescribed buspirone. His physician should inform the patient to anticipate

Answer 34

Ans: That the drug is likely to take a week or more to begin working Buspirone is a selective anxiolytic with pharmacologic characteristics different from those of sedative-hypnotics. Buspirone has minimal effects on cognition or memory; it is not an additive with ethanol in terms of CNS depression; tolerance is minimal; and it has no dependence liability. Buspirone is not effective in acute anxiety because it has a slow onset of action.

Question 35

An 82-year-old woman, otherwise healthy for her age, has difficulty sleeping. Triazolam is prescribed for her at one half of the conventional adult dose. Which statement about the use of triazolam in this elderly patient is accurate?

Answer 35

Ans: The patient may experience amnesia, especially if she also consumes alcoholic beverages In elderly patients taking benzodiazepines, hypotension is far more likely than an increase in blood pressure. Elderly patients are more prone to the CNS depressant effects of hypnotics; a dose reduction of 50% may still cause excessive sedation with possible ambulatory impairment. Additive CNS depression occurs commonly with drugs used in over-the-counter cold medications, and rebound insomnia can occur with abrupt discontinuance of benzodiazepines used as sleeping pills. Alcohol enhances psychomotor depression and the amnestic effects of the benzodiazepines.

Question 36

A 20-year-old woman is taking diphenhydramine for severe hay fever. Which of the following adverse effects is she most likely to report?

Answer 36

Ans: Sedation H1 blockers do not activate muscarinic receptors, mediate vasoconstriction, or cause uterine cramping. They do not cause nervousness or anxiety. Diphenhydramine is a potent sedative.

Question 37

A laboratory study of new H2 blockers is planned. Which of the following will result from blockade of H2 receptors?

Answer 37

Ans: Decreased cAMP in gastric mucosa H2 receptors are Gs-protein-coupled receptors, like beta adrenoceptors. Blockade of this system will cause a decrease in cAMP.

Question 38

Concerning the drugs used in parkinsonism, which statement is accurate?

Answer 38

Ans: Levodopa causes mydriasis and may precipitate an acute attack of glaucoma The non-ergot dopamine agonists (pramipexole, ropinirole) are commonly used prior to levodopa in mild parkinsonism. The mydriatic action of levodopa may increase intraocular pressure; the drug should be used cautiously in patients with open-angle glaucoma and is contraindicated in those with angle-closure glaucoma. Antimuscarinic drugs may improve the tremor and rigidity of parkinsonism but have little effect on bradykinesia. Selegiline is a selective inhibitor of MAO type B.

Question 39

The clinical use of succinylcholine, especially in patients with diabetes, is associated with

Answer 39

Ans: Aspiration of gastric contents Fasciculations associated with succinylcholine may increase intragastric pressure with possible complications of regurgitation and aspiration of gastric contents. The complication is more likely in patients with delayed gastric emptying such as those with esophageal dysfunction or diabetes. Histamine release resulting from succinylcholine is not genetically determined.

Question 40

A 58-year-old man with a history of hyperlipidemia was treated with a drug. The chart below shows the results of the patient's fasting lipid panel before treatment and 6 mo after initiating drug therapy. Normal values are also shown. Which of the following drugs is most likely to be the one that this man received? Trig Chol LDL VLDL HDL Before treatment 1000 640. 120 500. 20 Six months after 300 275. 90 150. 40 Normal values 35

Answer 40

Ans: Niacin This patient presents with striking hypertriglyceridemia, elevated VLDL cholesterol, and depressed HDL cholesterol. Six months after drug treatment was initiated, his triglyceride and VLDL cholesterol have dropped dramatically and his HDL cholesterol level has doubled. The drug that is most likely to have achieved all of these desirable changes, particularly the large increase in HDL cholesterol, is niacin. Although gemfibrozil lowers triglyceride and VLDL concentrations, it does not cause such large increases in HDL cholesterol and decreases in LDL cholesterol.

Question 41

Which statement concerning the proposed mechanisms of action of anticonvulsant drugs is inaccurate?

Answer 41

Ans: Ethosuximide selectively blocks potassium ion (K+) channels in thalamic neurons The mechanism of action of phenylsuccinimides such as ethosuximide involves blockade of T-type Ca2+ channels in thalamic neurons. Ethosuximide does not block K+ channels, which in any case would be likely to result in an increase (rather than a decrease) in neuronal excitability.

Question 42

Which of the following drugs inhibits thromboxane synthesis much more effectively than prostacyclin synthesis?

Answer 42

Ans: Aspirin Hydrocortisone and other corticosteroids inhibit phospholipase. Ibuprofen and indomethacin inhibit cyclooxygenase reversibly, whereas zileuton inhibits lipoxygenase. Because aspirin inhibits cyclooxygenase irreversibly, its action is more effective in platelets, which lack the ability to synthesize new enzyme, than in the endothelium.

Question 43

A 35-year-old woman appears to have familial combined hyperlipidemia. Her serum concentrations of total cholesterol, LDL cholesterol, and triglyceride are elevated. Her serum concentration of HDL cholesterol is somewhat reduced. If this patient is pregnant, which of the following drugs should be avoided because of a risk of harming the fetus?

Answer 43

Ans: Pravastatin The HMG-CoA reductase inhibitors are contraindicated in pregnancy because of the risk of teratogenic effects.

Question 44

The most likely explanation for the increased sensitivity of elderly patients after administration of a single dose of a benzodiazepine is

Answer 44

Ans: Changes in brain function accompanying aging Decreased blood flow to vital organs, including the liver and kidney, occurs during the aging process. These changes may contribute to cumulative effects of sedative-hypnotic drugs. However, this does not explain the enhanced sensitivity of the elderly patient to a single dose of a central depressant, which appears to be due to changes in brain function that accompany aging.

Question 45

A 30-year-old male patient is on drug therapy for a psychiatric problem. He complains that he feels "flat" and that he gets confused at times. He has been gaining weight and has lost his sex drive. As he moves his hands, you notice a slight tremor. He tells you that since he has been on medication he is always thirsty and frequently has to urinate. The drug he is most likely to be taking is

Answer 45

Ans: Lithium Confusion, mood changes, decreased sexual interest, and weight gain are symptoms that may be unrelated to drug administration. On the other hand, psychiatric drugs are often responsible for such symptoms. Tremor and symptoms of nephrogenic diabetes insipidus are characteristic adverse effects of lithium that may occur at blood levels within the therapeutic range.

Question 46

SSRIs are much less effective than tricyclic antidepressants in the management of

Answer 46

Ans: Chronic pain of neuropathic origin The SSRIs are not effective in chronic pain of neuropathic origin. All the other uses of SSRIs are approved indications with clinical effectiveness equivalent or superior to that of tricyclic drugs. In addition to treatment of chronic pain states and depression, the tricyclics are also used to treat enuresis and attention deficit hyperkinetic disorder.

Question 47

A previously healthy 40-year-old woman begins to suffer from slowed mentation, lack of coordination, and brief writhing movements of her hands that are not rhythmic. In addition, she has delusions of being persecuted. The woman has no history of psychiatric or neurologic disorders. Although further diagnostic assessment should be made, it is very likely that the most appropriate drug for treatment will be

Answer 47

Ans: Tetrabenazine Although further diagnosis is desirable, choreoathetosis with decreased mental abilities and psychosis (paranoia) suggests that this patient has the symptoms of Huntington's disease. Drugs that are partly ameliorative include agents that deplete dopamine (eg, tetrabenazine) or that block dopaminergic receptors (eg, haloperidol).

Question 48

A 43-year-old man has heterozygous familial hypercholesterolemia. His serum concentrations of total cholesterol and LDL are markedly elevated. His serum concentration of HDL cholesterol, VLDL cholesterol, and triglycerides are normal or slightly elevated. The patient’s mother and older brother died of myocardial infarctions before the age of 50. This patient recently experienced mild chest pain when walking upstairs and has been diagnosed as having angina of effort. The patient is somewhat overweight. He drinks alcohol most evenings and smokes about 1 pack of cigarettes per week. Consumption of alcohol is associated with which of the following changes in serum lipid concentrations?

Answer 48

Ans: Increased triglyceride Chronic ethanol ingestion can increase serum concentrations of VLDL and triglycerides. This is one of the factors that places patients with alcoholism at risk of pancreatitis. Chronic ethanol ingestion also has the possibly beneficial effect of raising, not decreasing, serum HDL concentrations.

Question 49

Which of the following drugs is most likely to be of value in obsessive-compulsive disorders?

Answer 49

Ans: Clomipramine Clomipramine, a tricyclic agent, is a more selective inhibitor of 5-HT reuptake than other drugs in its class. This activity appears to be important in the treatment of obsessive-compulsive disorder. However, the SSRIs have now become the drugs of choice for this disorder because they are safer in overdose than tricyclics.

Question 50

A 35-year-old woman appears to have familial combined hyperlipidemia. Her serum concentrations of total cholesterol, LDL cholesterol, and triglyceride are elevated. Her serum concentration of HDL cholesterol is somewhat reduced. Which of the following is a major toxicity associated with gemfibrozil therapy?

Answer 50

Ans: Cholelithiasis A major toxicity of the fibrates is increased risk of gallstone formation, which may be due to enhanced biliary excretion of cholesterol.

Question 51

Inflammation is a complex tissue reaction that includes the release of cytokines, leukotrienes, prostaglandins, and peptides. Prostaglandins involved in inflammatory processes are typically produced from arachidonic acid by which of the following enzymes?

Answer 51

Ans: Cyclooxygenase-2 See Figure 18–1. Phospholipase A2 converts membrane phospholipid to arachidonic acid. Cyclooxygenases convert arachidonic acid to prostaglandins. COX-2 is the enzyme believed to be responsible for this reaction in inflammatory cells.

Question 52

A young female patient suffers from absence seizures. Which of the following statements about her proposed drug management is NOT accurate?

Answer 52

Ans: She should be examined every 2 or 3 mo for deep tendon reflex activity Ethosuximide and valproic acid are preferred drugs in absence seizures because they cause minimal sedation. However, valproic acid causes gastrointestinal distress and weight gain and is potentially hepatotoxic. In addition, its use in pregnancy has been associated with teratogenicity (neural tube defects). Peripheral neuropathy, including diminished deep tendon reflexes in the lower extremities, occurs with the chronic use of phenytoin, not valproic acid.

Question 53

Which drug used in management of seizure disorders is most likely to elevate the plasma concentration of other drugs administered concomitantly?

Answer 53

Ans: Valproic acid With chronic use, carbamazepine induces the formation of hepatic drug-metabolizing enzymes (as do phenobarbital and phenytoin). This action may lead to a decrease in the plasma concentration of other drugs used concomitantly. Valproic acid, an inhibitor of drug metabolism, can increase the plasma levels of many drugs, including carbamazepine, lamotrigine, phenobarbital, and phenytoin. Benzodiazepines (including clonazepam and diazepam), as well as gabapentin and vigabatrin, have no major effects on the metabolism of other drugs.

Question 54

You are asked to consult on a series of cases of drug toxicities. Which of the following is a recognized adverse effect of cimetidine?

Answer 54

Ans: P450 hepatic enzyme inhibition The older H1 blockers, not H2 blockers, cause blurred vision, orthostatic hypotension, and sleepiness. Neither group typically causes diarrhea. Cimetidine (unlike other H2 blockers) is a potent CYP3A4 inhibitor.

Question 55

Which of the following in its parenteral form is life-saving in severe status asthmaticus and acts, at least in part, by inhibiting phospholipase A2?

Answer 55

Ans: Prednisone Parenteral corticosteroids such as prednisolone (the active metabolite of prednisone) are lifesaving in status asthmaticus. They probably act by reducing production of leukotrienes

Question 56

A 40-year-old patient is about to undergo cancer chemotherapy with a highly emetogenic (nausea- and vomiting-causing) drug combination. The antiemetic drug most likely to be included in her regimen is

Answer 56

Ans: Ondansetron Ondansetron and other 5-HT3 antagonists have significant antiemetic effects. Diphenhydramine and prednisone are also used for this purpose.

Question 57

A patient with a bleeding tendency presents in the hematology clinic. He is apparently taking large amounts of an unidentified drug that inhibits platelet activity. Which of the following directly and reversibly inhibits platelet cyclooxygenase?

Answer 57

Ans: ibuprofen Aspirin is a direct but irreversible inhibitor of cyclooxygenase. NSAIDs other than aspirin (such as ibuprofen) are reversible inhibitors of COX. Corticosteroids reduce the synthesis of cyclooxygenase.

Question 58

A newborn infant is diagnosed with transposition of the great vessels, wherein the aorta exits from the right ventricle and the pulmonary artery from the left ventricle. Which of the following drugs is likely to be used in preparation for surgical correction of this anomaly?

Answer 58

Ans: Prostaglandin PGE2 Infants with great vessel transposition pump venous blood to the aorta and oxygenated blood back to the lungs. Therefore, they require surgical correction as soon as they are strong enough to withstand the procedure. In the meantime, they are dependent on a patent ductus arteriosus to allow some oxygenated blood to flow from the left ventricle via the pulmonary artery to the aorta. The ductus can be prevented from closing by infusing the vasodilator PGE2.

Question 59

A 22-year-old man is brought to the emergency department after suffering seizures resulting from an overdose of a drug he has been taking. His friends state that he took the drug orally and sometimes had insomnia after taking it. Which of the following is a direct bronchodilator that is most often used in asthma by the oral route and is capable of causing insomnia and seizures?

Answer 59

Ans: Theophylline Theophylline is a bronchodilator that is active by the oral route. It causes insomnia in therapeutic doses and seizures in overdosage.

Question 60

A recently bereaved 73-year-old female patient was treated with a benzodiazepine for several weeks after the death of her husband, but she did not like the daytime sedation it caused even at low dosage. Living independently, she has no major medical problems but appears rather infirm for her age and has poor eyesight. Because her depressive symptoms are not abating, you decide on a trial of an antidepressant medication. Which of the following drugs would be the most appropriate choice for this patient?

Answer 60

Ans: Sertraline Older patients are more likely to be sensitive to antidepressant drugs that cause sedation, atropine-like adverse effects, or postural hypotension. Tricyclics and MAO inhibitors cause many autonomic side effects; mirtazapine and trazodone are highly sedating. Sertraline (or another SSRI) is often the best choice in such patients.

Question 61

This drug, an antagonist at 5-HT2 receptors, is widely used for the management of insomnia.

Answer 61

Ans: Trazodone Triazolam and zolpidem are effective hypnotic drugs, but they do not act via antagonism of serotonin 5-HT2 receptors. Trazodone is an antagonist at 5-HT2 receptors and has wide use as a sleeping aid, especially in patients with symptoms of affective disorder.

Question 62

A young male patient recently diagnosed as schizophrenic develops severe muscle cramps with torticollis a short time after drug therapy is initiated with haloperidol. The best course of action would be to

Answer 62

Ans: Inject benztropine Acute dystonic reactions are usually very painful and should be treated immediately with parenteral administration of a drug that blocks muscarinic receptors such as benztropine. Adding risperidone is not protective, and fluphenazine is as likely as haloperidol to cause acute dystonia. Oral administration of diphenhydramine is a possibility, but the patient may find it difficult to swallow and it would take a longer time to act.

Question 63

Which drug is most often associated with hypotension caused by histamine release?

Answer 63

Ans: Tubocurarine Hypotension may occur with tubocurarine and with the spasmolytic drug tizanidine. In the case of tubocurarine, the decrease in blood pressure may be due partly to histamine release and to ganglionic blockade. Tizanidine causes hypotension via 2-adrenoceptor activation like its congener clonidine.

Question 64

Which statement concerning the pharmacokinetics of antiseizure drugs is accurate?

Answer 64

Ans: Although ethosuximide has a half-life of approximately 40 h, the drug is usually taken twice a day The enzyme-inducing activity of phenytoin has led to symptoms of opioid withdrawal, presumably because of an increase in the rate of metabolism of methadone. Monitoring of plasma concentration of phenytoin may be critical in establishing an effective dosage because of nonlinear elimination kinetics at high doses. Valproic acid has no effect on porphyrin synthesis. Vigabatrin does not affect the metabolism of oral contraceptives. Twice-daily dosage of ethosuximide reduces the severity of adverse gastrointestinal effects.

Question 65

Which drug used in the maintenance treatment of patients with tonic-clonic or partial seizure states increases the hepatic metabolism of many drugs including both warfarin and phenytoin?

Answer 65

Ans: Phenobarbital Chronic administration of phenobarbital increases the activity of hepatic drug-metabolizing enzymes, including several cytochrome P450 isozymes. This can increase the rate of metabolism of drugs administered concomitantly, resulting in decreases in the intensity and duration of their effects.

Question 66

A 35-year-old woman appears to have familial combined hyperlipidemia. Her serum concentrations of total cholesterol, LDL cholesterol, and triglyceride are elevated. Her serum concentration of HDL cholesterol is somewhat reduced. The patient is started on gemfibrozil. Which of the following is a major mechanism of gemfibrozil’s action?

Answer 66

Ans: Increased triglyceride hydrolysis by lipoprotein lipase A major mechanism recognized for gemfibrozil is increased activity of the lipoprotein lipase associated with capillary endothelial cells. Gemfibrozil and other fibrates decrease VLDL secretion, presumably by stimulating hepatic fatty acid oxidation.

Question 67

Which drug is most likely to cause hyperkalemia leading to cardiac arrest in patients with extensive burns?

Answer 67

Ans: Succinylcholine Skeletal muscle depolarization by succinylcholine releases potassium from the cells, and the ensuing hyperkalemia can be life-threatening in terms of cardiac arrest. Patients most susceptible include those with extensive burns, spinal cord injuries, neurologic dysfunction, or intra-abdominal infection.

Question 68

In comparing the characteristics of thioridazine with other older antipsychotic drugs, which of the following statements is accurate?

Answer 68

Ans: Most likely to cause ocular dysfunction Atropine-like side effects are more prominent with thioridazine than with other phenothiazines, but the drug is less likely to cause extrapyramidal dysfunction. The drug has quinidine-like actions on the heart and, in overdose, may cause arrhythmias and cardiac conduction block with fatality. At high doses, thioridazine causes retinal deposits, which in advanced cases resemble retinitis pigmentosa. The patient may complain of browning of vision.

Question 69

Which of the following drugs is the most effective in the emergency management of malignant hyperthermia?

Answer 69

Ans: Dantrolene Prompt treatment is essential in malignant hyperthermia to control body temperature, correct acidosis, and prevent calcium release. Dantrolene interacts with the RyR1 channel to block the release of activator calcium from the sarcoplasmic reticulum, which prevents the tension-generating interaction of actin with myosin.

Question 70

Which of the following drugs is established to be both effective and safe to use in a pregnant patient suffering from bipolar disorder?

Answer 70

Ans:Quetiapine Carbamazepine and valproic acid are effective in bipolar disorder but are contraindicated in the pregnant patient because of possible effects on fetal development. Although the potential for dysmorphogenesis due to lithium is probably low, the most conservative approach would be to treat the patient with quetiapine or olanzapine. Chlorpromazine has no proven efficacy in bipolar disorder.

Question 71

A 26-year-old woman presents with amenorrhea and galactorrhea. Her prolactin level is grossly elevated. Which of the following is most useful in the treatment of hyperprolactinemia?

Answer 71

Ans: Bromocriptine Bromocriptine is an effective dopamine agonist in the CNS with the advantage of oral activity. The drug inhibits prolactin secretion by activating pituitary dopamine receptors.

Question 72

You have been treating a 50-year-old woman with moderately severe arthritis with nonsteroidal anti-inflammatory drugs for 6 months. She now complains of heartburn and indigestion. You give her a prescription for a drug to be taken along with the anti-inflammatory agent, but 2 days later she calls the office complaining that your last prescription has caused severe diarrhea. Which of the following is most likely to be associated with increased gastrointestinal motility and diarrhea?

Answer 72

Ans: Misoprostol Aspirin, corticosteroids, and zileuton do not cause diarrhea. LTB4 is a chemotactic factor.

Question 73

A 43-year-old man has heterozygous familial hypercholesterolemia. His serum concentrations of total cholesterol and LDL are markedly elevated. His serum concentration of HDL cholesterol, VLDL cholesterol, and triglycerides are normal or slightly elevated. The patient's mother and older brother died of myocardial infarctions before the age of 50. This patient recently experienced mild chest pain when walking upstairs and has been diagnosed as having angina of effort. The patient is somewhat overweight. He drinks alcohol most evenings and smokes about 1 pack of cigarettes per week. After being counseled about lifestyle and dietary changes, the patient was started on atorvastatin. During his treatment with atorvastatin, it is important to routinely monitor serum concentrations of which of the following?

Answer 73

Ans: Alanine and aspartate aminotransferase The 2 primary adverse effects of the HMG-CoA reductase inhibitors are hepatotoxicity and myopathy. Patients taking these drugs should have liver function tests performed before starting therapy, and at regular intervals during therapy. Serum concentrations of alanine and aspartate aminotransferase are used as markers of hepatocellular toxicity.

Question 74

With chronic use in seizure states, the adverse effects of this drug include coarsening of facial features, hirsutism, and gingival hyperplasia.

Answer 74

Ans: Phenytoin Common adverse effects of phenytoin include nystagmus, diplopia, and ataxia. With chronic use, abnormalities of vitamin D metabolism, coarsening of facial features, gingival overgrowth, and hirsutism may also occur.

Question 75

Which drug has spasmolytic activity and could also be used in the management of seizures caused by overdose of a local anesthetic?

Answer 75

Ans: Diazepam Diazepam is both an effective antiseizure drug and a spasmolytic. The spasmolytic action of diazepam is thought to be exerted partly in the spinal cord because it reduces spasm of skeletal muscle in patients with cord transection. Cyclobenzaprine is used for acute local spasm and has no antiseizure activity.

Question 76

A patient under treatment for a major depressive disorder is brought to the emergency department after ingesting 30 times the normal daily therapeutic dose of amitriptyline. In severe tricyclic antidepressant overdose, it would be of minimal value to

Answer 76

Ans: Initiate hemodialysis (to hasten drug elimination) TCA overdose is a medical emergency. The "3 Cs"—coma, convulsions, and cardiac problems—are the most common causes of death. Widening of the QRS complex on the ECG is a major diagnostic feature of cardiac toxicity. Arrhythmias resulting from cardiac toxicity require the use of drugs with the least effect on cardiac conductivity (eg, lidocaine). Hemodialysis does not increase the rate of elimination of tricyclic antidepressants in overdose.

Question 77

Which of the following drugs has a high affinity for 5-HT2 receptors in the brain, does not cause extrapyramidal dysfunction or hematotoxicity, and is reported to increase the risk of significant QT prolongation?

Answer 77

Ans: Ziprasidone Many of the newer antipsychotic drugs have a greater affinity for 5-HT2 receptors than dopamine receptors. However, because clozapine is hematotoxic, the choice comes down to olanzapine and ziprasidone, both of which block 5-HT receptors. Of the currently available atypical antipsychotic drugs, ziprasidone carries the greatest risk of QT prolongation.

Question 78

The mechanism of antiseizure activity of carbamazepine is

Answer 78

Ans: Block of sodium ion channels The mechanism of action of carbamazepine is similar to that of phenytoin, blocking sodium ion channels. Ethosuximide blocks calcium channels; benzodiazepines and barbiturates facilitate the inhibitory actions of GABA; topiramate may block glutamate receptors; and vigabatrin inhibits GABA metabolism.

Question 79

With respect to ropinirole, which of the following is accurate?

Answer 79

Ans: All the Above - Activates brain dopamine D3 receptors - Effective as monotherapy in mild parkinsonism - May cause postural hypotension - Not an ergot derivative Ropinirole is a non-ergot agonist at dopamine receptors and has greater selectivity for D2 receptors in the striatum. Ropinirole (or the D3 receptor antagonist pramipexole) is often chosen for monotherapy of mild parkinsonism, and these drugs sometimes have value in patients who have become refractory to levodopa. Adverse effects of these drugs include dyskinesias, postural hypotension, and somnolence.

Question 80

Abrupt withdrawal of antiseizure drugs can result in increases in seizure frequency and severity. Withdrawal is most easily accomplished if the patient is being treated with

Answer 80

Ans: Ethosuximide Dose tapering is an important principle in antiseizure drug withdrawal. As a rule, withdrawal from drugs used for absence seizures is easier than withdrawal from drugs used for partial and tonic-clonic seizures. Withdrawal is most difficult in patients who have been treated with barbiturates and benzodiazepines.

Question 81

Which of the following is a leukotriene receptor blocker?

Answer 81

Ans:Zafirlukast Zileuton blocks the synthesis of leukotrienes. Zafirlukast and montelukast block LTD4 receptors.

Question 82

A 17-year-old patient complains that he develops wheezing and severe shortness of breath whenever he takes aspirin for headache. Increased levels of which of the following may be responsible, in part, for some cases of aspirin hypersensitivity?

Answer 82

Ans: Leukotriene LTC4 When cyclooxygenase is blocked, leukotrienes may be produced in increased amounts by diversion of prostaglandin precursors into the lipoxygenase pathway (Figure 18–1). In patients with aspirin hypersensitivity, this might precipitate the bronchoconstriction often observed in this condition.

Question 83

Which of the following has a slow onset but long duration of action and is always used in combination with a corticosteroid by inhalation?

Answer 83

Ans: Salmeterol Salmeterol is a Beta2-selective agonist that has a slow onset and long duration of action. Used alone, it increases asthma mortality, but in combination with inhaled corticosteroids it improves asthma control.

Question 84

The hospital Pharmacy Committee is preparing a formulary for staff use. Which of the following is a correct application of the drug mentioned?

Answer 84

Ans: Cetirizine: for hay fever Alosetron is indicated in irritable bowel syndrome. Ergonovine is used in uterine bleeding. Ondansetron is useful for chemotherapy-induced emesis. Cetirizine is used in the treatment of hay fever.

Question 85

A patient with liver dysfunction is scheduled for a surgical procedure. Lorazepam or oxazepam can be used for preanesthetic sedation in this patient without special concern regarding excessive CNS depression because these drugs are

Answer 85

Ans: Metabolized via conjugation extrahepatically The elimination of most benzodiazepines involves their metabolism by liver enzymes, including cytochrome P450 isozymes. In a patient with liver dysfunction, lorazepam and oxazepam, which are metabolized extrahepatically, are less likely to cause excessive CNS depression. Benzodiazepines are not eliminated via the kidneys or lungs. Flumazenil is used to reverse excessive CNS depression caused by benzodiazepines.

Question 86

Regarding the spasmolytic drugs, which of the following statements is not accurate?

Answer 86

Ans: Baclofen acts on GABA receptors in the spinal cord to increase chloride ion conductance Baclofen activates GABA-B receptors in the spinal cord. However, these receptors are coupled to K+ channels. GABA-A receptors in the CNS modulate chloride ion channels, an action facilitated by diazepam and other benzodiazepines.

Question 87

A 43-year-old man has heterozygous familial hypercholesterolemia. His serum concentrations of total cholesterol and LDL are markedly elevated. His serum concentration of HDL cholesterol, VLDL cholesterol, and triglycerides are normal or slightly elevated. The patient's mother and older brother died of myocardial infarctions before the age of 50. This patient recently experienced mild chest pain when walking upstairs and has been diagnosed as having angina of effort. The patient is somewhat overweight. He drinks alcohol most evenings and smokes about 1 pack of cigarettes per week. If the patient has a history of gout, which of the following drugs is most likely to exacerbate this condition?

Answer 87

Ans: Niacin Niacin can exacerbate both hyperuricemia and glucose intolerance.

Question 88

A 43-year-old man has heterozygous familial hypercholesterolemia. His serum concentrations of total cholesterol and LDL are markedly elevated. His serum concentration of HDL cholesterol, VLDL cholesterol, and triglycerides are normal or slightly elevated. The patient's mother and older brother died of myocardial infarctions before the age of 50. This patient recently experienced mild chest pain when walking upstairs and has been diagnosed as having angina of effort. The patient is somewhat overweight. He drinks alcohol most evenings and smokes about 1 pack of cigarettes per week. Six months after beginning atorvastatin, the patient’s total and LDL cholesterol concentrations remained above normal, and he continued to have anginal attacks despite good adherence to his antianginal medications. His physician decided to add ezetimibe. Which of the following is the most accurate description of ezetimibe’s mechanism of an action?

Answer 88

Ans: Decreased gastrointestinal absorption of cholesterol The major recognized effect of ezetimibe is inhibition of absorption of cholesterol in the intestine.

Question 89

Which of the following is a component of slow-reacting substance of anaphylaxis (SRS-A)?

Answer 89

Ans: Leukotriene LTC4 The leukotriene C and D series are major components of SRS-A. Leukotriene LTB4 is a chemotactic eicosanoid.

Question 90

A young male patient suffers from a seizure disorder characterized by tonic rigidity of the extremities followed in 15–30 s of tremor progressing to massive jerking of the body. This clonic phase lasts for 1 or 2 min, leaving the patient in a stuporous state. Of the following drugs, which is most suitable for long-term management of this patient?

Answer 90

Ans: Carbamazepine This patient is suffering from generalized tonic-clonic seizures. For many years, the drugs of choice in this seizure disorder have been carbamazepine or phenytoin or valproic acid. However, many newer drugs are also effective, including gabapentin, lamotrigine, levetiracetem, topiramate, and zonisamide. Clonazepam and ethosuximide are not effective in this type of seizure disorder. Fosphenytoin is available for parenteral use in the management of status epilepticus. Tiagabine is approved for adjunctive use only in partial seizures.

Question 91

A 28-year-old office worker suffers from intense migraine headaches. Which of the following is a serotonin agonist useful for aborting an acute migraine headache?

Answer 91

Ans: Sumatriptan Sumatriptan, an agonist at 5-HT1D receptors, is indicated for prevention or treatment of migraine and cluster headaches. Ergotamine (not on the list) is also effective for acute migraine but is produced by the fungus Claviceps purpurea.

Question 92

Entacapone may be of value in patients being treated with levodopa-carbidopa because it

Answer 92

Ans: Decreases the formation of 3-O-methyldopa Entacapone is an inhibitor of COMT used adjunctively in patients treated with levodopa-carbidopa. The drug decreases the formation of 3-O-methyldopa (3-OMD) from levodopa. This can improve patient response by increasing levodopa levels and by decreasing competition between 3-OMD and levodopa for active transport into the brain by L-amino acid carrier mechanism.

Question 93

Which statement about phenytoin is accurate?

Answer 93

Ans: Toxic effects may occur with only small increments in dose Sulfonamides can displace phenytoin from its binding sites, increasing the plasma-free fraction of the drug. Induction of liver drug-metabolizing enzymes by phenobarbital results in a decreased half-life of phenytoin, and isoniazid increases plasma levels of phenytoin by inhibiting its metabolism. Because of the dose-dependent elimination kinetics of phenytoin, some toxicity may occur with only small increments in dose.

Question 94

To be effective in breast cancer, tamoxifen must be converted to an active form by CYP2D6. Cases of inadequate treatment of breast cancer have occurred when tamoxifen was administered to patients who were being treated with

Answer 94

Ans: Fluoxetine Fluoxetine is an inhibitor of hepatic cytochromes P450 especially CYP2D6, and to a lesser extent CYP3A4. Dosages of several drugs may need to be reduced if given concomitantly with fluoxetine. In the case of tamoxifen, however, its antineoplastic action is dependent on its conversion to an active metabolite by CYP2D6.

Question 95

This drug used in the management of insomnia facilitates the inhibitory actions of GABA, but it lacks anticonvulsant or muscle-relaxing properties and has minimal effect on sleep architecture. Its actions are antagonized by flumazenil.

Answer 95

Ans: Eszopiclone Only two of the drugs listed are used for insomnia, eszopiclone and ramelteon. Eszopiclone, zaleplon, and zolpidem are related hypnotics that, though structurally different from benzodiazepines, appear to have a similar mechanism of action. However, these drugs are not effective in seizures or in muscle spasticity states. Compared with benzodiazepines, the newer hypnotics are less likely to alter sleep patterns. Ramelteon activates melatonin receptors in the suprachiasmatic nuclei. Buspirone is not a hypnotic!

Question 96

Which of the following drugs is most suitable for management of tremor in a patient who has pulmonary disease?

Answer 96

Ans: Metoprolol Increased activation of beta adrenoceptors has been implicated in essential tremor, and management commonly involves administration of propranolol. However, the more selective beta1 blocker metoprolol is equally effective and is more suitable in a patient with pulmonary disease.

Question 97

Myalgias are a common postoperative complaint of patients who receive large doses of succinylcholine, possibly the result of muscle fasciculations caused by depolarization. Which drug administered in the operating room can be used to prevent postoperative pain caused by succinylcholine?

Answer 97

Ans: Cisatracurium The depolarizing action of succinylcholine at the skeletal muscle end plate can be antagonized by small doses of depolarizing blockers. To prevent skeletal muscle fasciculations and the resulting postoperative pain caused by succinylcholine, a small nonparalyzing dose of a nondepolarizing drug is often given immediately before succinylcholine.

Question 98

A 33-year-old woman attempted to induce an abortion using ergotamine. Her legs became cold with absent arterial pulses. Which of the following is the most useful antidote for reversing severe ergot-induced vasospasm?

Answer 98

Ans: Nitroprusside A very powerful vasodilator is necessary to reverse ergot-induced vasospasm; nitroprusside is such a drug

Question 99

Among NSAIDs, aspirin is unique because it

Answer 99

Ans: Irreversibly inhibits its target enzyme Aspirin differs from other NSAIDs by irreversibly inhibiting cyclooxygenase.

Question 100

Which of the following is an analgesic and antipyretic drug that lacks an anti-inflammatory action?

Answer 100

Ans: Acetaminophen Acetaminophen is the only drug that fits this description. Indomethacin is a nonselective COX inhibitor and celecoxib is a COX-2 inhibitor; both have analgesic, antipyretic, and anti-inflammatory effects. Colchicine is a drug used for gout that also has an anti-inflammatory action. Probenecid is a uricosuric drug that promotes the excretion of uric acid.

Question 101

Which of the following drugs is most likely to increase serum concentrations of conventional doses of methotrexate, a weak acid that is primarily cleared in the urine?

Answer 101

Ans: Probenecid Like other weak acids, methotrexate depends on active tubular excretion in the proximal tubule for efficient elimination. Probenecid competes with methotrexate for binding to the proximal tubule transporter and thereby decreases the rate of clearance of methotrexate.

Question 102

The main advantage of ketorolac over aspirin is that ketorolac

Answer 102

Ans: Is available in a parenteral formulation that can be injected intramuscularly or intravenously Ketorolac exerts typical NSAID effects. It prolongs the bleeding time and can impair renal function, especially in a patient with preexisting renal disease. Its primary use is as a parenteral agent for pain management, especially for treatment of postoperative patients.

Question 103

A 16-year-old girl comes to the emergency department suffering from the effects of an aspirin overdose. Which of the following syndromes is this patient most likely to exhibit as a result of this drug overdose?

Answer 103

Ans: Hyperthermia, metabolic acidosis, and coma Salicylate intoxication is associated with metabolic acidosis, dehydration, and hyperthermia. If these problems are not corrected, coma and death ensue.

Question 104

An 18-month-old boy dies from an accidental overdose of acetaminophen. Which of the following is the most likely cause of this patient's death?

Answer 104

Ans: Liver failure In overdose, acetaminophen causes fulminant liver failure as a result of its conversion by hepatic cytochrome P450 enzymes to a highly reactive metabolite.

Question 105

A 54-year-old woman presented with signs and symptoms consistent with an early stage of rheumatoid arthritis. The decision was made to initiate NSAID therapy. Which of the following patient characteristics is the most compelling reason for avoiding celecoxib in the treatment of her arthritis?

Answer 105

Ans: History of myocardial infarction Celecoxib is a COX-2-selective inhibitor. Although the COX-2 inhibitors have the advantage over nonselective NSAIDs of reduced gastrointestinal toxicity, clinical data suggest that they are more likely to cause arterial thrombotic events. A history of myocardial infarction would be a compelling reason to avoid a COX-2 inhibitor.

Question 106

A 52-year-old woman presented with intense pain, warmth, and redness in the first toe on her left foot. Examination of fluid withdrawn from the inflamed joint revealed crystals of uric acid. In the treatment of this woman's acute attack of gout, a high dose of colchicine will reduce the pain and inflammation. However, many physicians prefer to treat acute gout with a corticosteroid or indomethacin because high doses of colchicine are likely to cause

Answer 106

Ans: Severe diarrhea At doses needed to treat acute gout, colchicine frequently causes significant diarrhea. Such gastrointestinal effects are less likely with the lower doses used in chronic gout.

Question 107

A 54-year-old woman presented with signs and symptoms consistent with an early stage of rheumatoid arthritis. The decision was made to initiate NSAID therapy. Although the patient's disease was adequately controlled with an NSAID and methotrexate for some time, her symptoms began to worsen and radiologic studies of her hands indicated progressive destruction in the joints of several fingers. Treatment with another second-line agent for rheumatoid arthritis was considered. Which of the following is a parenterally administered DMARD whose mechanism of anti-inflammatory action is antagonism of tumor necrosis factor?

Answer 107

Ans: Etanercept Etanercept is a recombinant protein that binds to tumor necrosis factor and prevents its inflammatory effects.

Question 108

A 52-year-old woman presented with intense pain, warmth, and redness in the first toe on her left foot. Examination of fluid withdrawn from the inflamed joint revealed crystals of uric acid. Over the next 7 mo, the patient had 2 more attacks of acute gout. Her serum concentration of uric acid was elevated. The decision was made to put her on chronic drug therapy to try to prevent subsequent attacks. Which of the following drugs could be used to decrease this woman's rate of production of uric acid?

Answer 108

Ans: Allopurinol Allopurinol is the only drug listed that decreases production of uric acid. Probenecid increases uric acid excretion. Colchicine and hydroxychloroquine do not affect uric acid metabolism. Aspirin actually slows renal secretion of uric acid and raises uric acid blood levels. It should not be used in gout.

Question 109

A 24-year-old woman was found to have mild hyperthyroidism due to Graves' disease. She appears to be in good health otherwise. In Graves' disease, the cause of the hyperthyroidism is the production of an antibody that does which of the following?

Answer 109

Ans: Activates the thyroid gland TSH receptor and stimulates thyroid hormone synthesis and release The antibodies produced in Graves' disease activate thyroid gland TSH receptors. Their effects mimic those of TSH.

Question 110

A 24-year-old woman was found to have mild hyperthyroidism due to Graves' disease. She appears to be in good health otherwise. The decision is made to begin treatment with methimazole. Methimazole reduces serum concentration of T3 primarily by which of the following mechanisms?

Answer 110

Ans: Preventing the addition of iodine to tyrosine residues on thyroglobulin The thioamides (methimazole and propylthiouracil) act in thyroid cells to prevent conversion of tyrosine residues in thyroglobulin to MIT or DIT.

Question 111

This antiarrhythmic drug that inhibits peripheral conversion of T4 to T3 is

Answer 111

Ans: Amiodarone Amiodarone is an iodine-containing antiarrhythmic drug with complex effects on the thyroid gland and thyroid hormones. One of its actions is to inhibit peripheral conversion of T4 to T3.

Question 112

A 56-year-old woman presented to the emergency department with tachycardia, shortness of breath, and chest pain. She had had shortness of breath and diarrhea for the last 2 d and was sweating and anxious. A relative reported that the patient had run out of methimazole 2 wk earlier. A TSH measurement revealed a value of

Answer 112

Ans: Propranolol In thyroid storm, beta blockers such as propranolol are useful in controlling the tachycardia and other cardiac abnormalities, and propranolol also inhibits peripheral conversion of T4 to T3.

Question 113

A 65-year-old man with multinodular goiter is scheduled for a near-total thyroidectomy. Which of the following drugs will be administered for 10–14 d before surgery to reduce the vascularity of his thyroid gland?

Answer 113

Ans: Lugol's solution Iodides inhibit the synthesis and release of thyroid hormone and decrease the size and vascularity of the hyperplastic gland. Lugol's solution contains a mixture of potassium iodide and iodine.

Question 114

A 24-year-old woman was found to have mild hyperthyroidism due to Graves' disease. She appears to be in good health otherwise. Though rare, a serious toxicity associated with the thioamides is which of the following?

Answer 114

Ans: Agranulocytosis Rarely, the thioamides cause severe adverse reactions that include agranulocytosis, vasculitis, hepatic damage, and hypoprothrombinemia.

Question 115

Which of the following is a sign or symptom that would be expected to occur in the event of chronic overdose with exogenous T4?

Answer 115

Ans: Weight loss In hyperthyroidism, the metabolic rate increases, and even though there is increased appetite, weight loss often occurs. The other choices are symptoms seen in hypothyroidism.

Question 116

When initiating T4 therapy for an elderly patient with longstanding hypothyroidism, it is important to begin with small doses to avoid which of the following?

Answer 116

Ans: Overstimulation of the heart Patients with longstanding hypothyroidism, especially those who are elderly, are highly sensitive to the stimulatory effects of T4 on cardiac function. Administration of regular doses can cause overstimulation of the heart and cardiac collapse.

Question 117

Hormone produced in the peripheral tissues when T4 is administered is most closely associated with

Answer 117

Ans: Triiodothyronine T4 is converted into T3 in the periphery.

Question 118

This drug that produces a permanent reduction in thyroid activity is

Answer 118

Ans: I-131 Radioactive iodine is the only medical therapy that produces a permanent reduction of thyroid activity.

Question 119

A 46-year-old male patient has Cushing's syndrome that is due to the presence of an adrenal tumor. Which of the following drugs would be expected to reduce the signs and symptoms of this man's disease?

Answer 119

Ans: Ketoconazole Ketoconazole inhibits many types of cytochrome P450 enzymes. It can be used to reduce the unregulated overproduction of corticosteroids by adrenal tumors.

Question 120

A 34-year-old woman with ulcerative colitis has required long-term treatment with pharmacologic doses of a glucocorticoid agonist. Which of the following is a toxic effect associated with long-term glucocorticoid treatment?

Answer 120

Ans:Osteoporosis One of the adverse metabolic effects of long-term glucocorticoid therapy is a net loss of bone, which can result in osteoporosis.

Question 121

Which of the following is a pharmacologic effect of exogenous glucocorticoids?

Answer 121

Ans: Inhibition of leukotriene synthesis Glucocorticoids inhibit the production of both leukotrienes and prostaglandins. This is a key component of their anti-inflammatory action.

Question 122

Glucocorticoids have proved useful in the treatment of which of the following medical conditions?

Answer 122

Ans: Chemotherapy-induced vomiting Glucocorticoids are used in combination with other antiemetics to prevent chemotherapy-induced nausea and vomiting, which are commonly associated with anticancer drugs.

Question 123

A newborn girl exhibited ambiguous genitalia, hyponatremia, hyperkalemia, and hypotension as a result of genetic deficiency of 21-hydroxylase activity. Treatment consisted of fluid and salt replacement and hydrocortisone administration. In this type of adrenal hyperplasia in which there is excess production of cortisol precursors, which of the following describes the primary therapeutic effect of glucocorticoid administration?

Answer 123

Ans: Suppression of ACTH secretion A 21beta-hydroxylase deficiency prevents normal synthesis of cortisol and aldosterone, and causes accumulation of cortisol precursors (Figure 39–2). The hypothalamic-pituitary system responds to the abnormally low levels of cortisol by increasing ACTH release. High levels of ACTH induce adrenal hyperplasia and excess production of adrenal androgens, which can cause virilization of females and prepubertal males. Glucocorticoid is administered to replace the missing mineralocorticoid and glucocorticoid activity and to suppress ACTH release, which removes the stimulus for excess adrenal androgen production.

Question 124

Which of the following is a drug that, in high doses, blocks the glucocorticoid receptor?

Answer 124

Ans:Mifepristone Mifepristone is a competitive antagonist of glucocorticoid and progesterone receptors. Ketoconazole and aminoglutethimide also antagonize corticosteroids; however, they act by inhibiting steroid hormone synthesis.

Question 125

Which of the following best describes a glucocorticoid response element?

Answer 125

Ans: A specific nucleotide sequence that is recognized by a steroid hormone receptor-hormone complex Activated steroid hormone receptors mediate their effects on gene expression by binding to hormone response elements, which are short sequences of DNA located near steroid-regulated genes.

Question 126

A 54-year-old man with advanced tuberculosis has developed signs of severe acute adrenal insufficiency. The patient should be treated immediately. Which of the following combinations is most rational?

Answer 126

Ans: Cortisol and fludrocortisone A rational combination of drugs should include agents with complementary effects (ie, a glucocorticoid and a mineralocorticoid). The combination with these characteristics is cortisol and fludrocortisone. (Note that although fludrocortisone may have sufficient glucocorticoid activity for a patient with mild disease, a patient in severe acute adrenal insufficiency needs a full glucocorticoid such as cortisol.)

Question 127

A 56-year-old woman with systemic lupus erythematosus had been maintained on a moderate daily dose of prednisone for 9 mo. Her disease has finally gone into remission and she now wishes to gradually taper and then discontinue the prednisone. Gradual tapering of a glucocorticoid is required for recovery of which of the following?

Answer 127

Ans: The hypothalamic-pituitary-adrenal system Exogenous glucocorticoids act at the hypothalamus and pituitary to suppress the production of CRF and ACTH. As a result, adrenal production of endogenous corticosteroids is suppressed. On discontinuance, the recovery of normal hypothalamic-pituitary-adrenal function occurs slowly. Glucocorticoid doses must be tapered slowly, over several months, to prevent adrenal insufficiency.

Question 128

A 54-year-old man with advanced tuberculosis has developed signs of severe acute adrenal insufficiency. Which of the following signs or symptoms is this patient most likely to exhibit?

Answer 128

Ans: Dehydration In acute adrenal insufficiency, there is loss of salt and water that is primarily due to reduced production of aldosterone. The loss of salt and water can lead to dehydration.

Question 129

Which of the following is an estrogen that is used in most combined hormonal contraceptives?

Answer 129

Ans:Ethinyl estradiol Ethinyl estradiol, a synthetic estrogen with good bioavailability, is the estrogenic component of most combined oral contraceptives, the transdermal contraceptive, and the vaginal ring contraceptive.

Question 130

A 23-year-old woman desires a combined oral contraceptive for pregnancy protection. Which of the following patient factors would lead a health professional to recommend an alternative form of contraception?

Answer 130

Ans: History of migraine headache that is well controlled by sumatriptan Estrogen-containing hormonal contraceptives increase the risk of episodes of migraine headache.

Question 131

A 50-year-old woman with a positive mammogram undergoes lumpectomy and a small carcinoma is removed. Biochemical analysis of the cancer reveals the presence of estrogen and progesterone receptors. After this procedure, she will probably receive which of the following drugs?

Answer 131

Ans: Tamoxifen Tamoxifen has proved useful in adjunctive therapy of breast cancer; the drug decreases the rate of recurrence of cancer.

Question 132

Diethylstilbestrol (DES) should never be used in pregnant women because it is associated with which of the following?

Answer 132

Ans: Infertility and development of vaginal cancer in female offspring Diethylstilbestrol (DES) is a nonsteroidal estrogen agonist. Several decades ago, misguided use of the drug in pregnant women appears to have resulted in fetal damage that predisposed female offspring to infertility and a rare form of vaginal cancer. For this reason, the drug should be avoided in pregnant women. Other estrogenic drugs do not appear to have these same effects. Although estrogens do increase the risk of deep vein thrombosis, this is not the reason why DES should be avoided.

Question 133

A 60-year-old man is found to have a prostate lump and an elevated prostate-specific antigen (PSA) blood test. Magnetic resonance imaging suggests several enlarged lymph nodes in the lower abdomen, and an x-ray reveals 2 radiolucent lesions in the bony pelvis. This patient is likely to be treated with which of the following drugs?

Answer 133

Ans: Flutamide Antiandrogen drugs are used to treat metastatic prostate cancer because they have efficacy, whereas conventional cytotoxic drugs do not. Flutamide is a competitive antagonist of the androgen receptor that is used in combination with a GnRH agonist in the treatment of men with prostate cancer.

Question 134

Men who use large doses of anabolic steroids are at increased risk of which of the following?

Answer 134

Ans: Cholestatic jaundice and elevation of aspartate transaminase levels in the blood In men, large doses of anabolic steroids are associated with liver impairment, including cholestasis and elevation of serum concentrations of transaminases.

Question 135

A young woman complains of abdominal pain at the time of menstruation. Careful evaluation indicates the presence of significant endometrial deposits on the pelvic peritoneum. Which of the following is the most appropriate medical therapy for this patient?

Answer 135

Ans: Medroxyprogesterone acetate by intramuscular injection In endometriosis, suppression of ovarian function and production of gonadal steroids are useful. Intramuscular injection of relatively large doses of medroxyprogesterone provides 3 mo of an ovarian suppressive effect because of inhibition of pituitary production of gonadotropins.

Question 136

A 52-year-old postmenopausal patient has evidence of low bone mineral density. She and her physician are considering therapy with raloxifene or a combination of conjugated estrogens and medroxyprogesterone acetate. Which of the following patient characteristics is most likely to lead them to select raloxifene?

Answer 136

Ans: Strong family history of breast cancer Conjugated estrogens and raloxifene both improve bone mineral density and protect against osteoporosis. The 2 advantages of raloxifene over full estrogen receptor agonists are that raloxifene has antagonist effects in breast tissue and lacks an agonistic effect in endometrium. If a patient's uterus was removed by surgery, the difference in the endometrial effect is moot. In patients with a strong family history of breast cancer, raloxifene may be a better choice than a full estrogen agonist because it will not further increase the woman's risk of breast cancer and may even lower her risk.

Question 137

Which of the following is a unique property of SERMs?

Answer 137

Ans: Act as agonists in some tissues and antagonists in other tissues SERMs such as tamoxifen and raloxifene exhibit tissue-specific estrogenic and antiestrogenic effects.

Question 138

Finasteride has efficacy in the prevention of male-pattern baldness by virtue of its ability to do which of the following?

Answer 138

Ans: Reduce the production of dihydrotestosterone Finasteride inhibits 5-reductase, the enzyme that converts testosterone to DHT, the principal androgen in androgen-sensitive hair follicles.

Question 139

A 13-year-old boy with type 1 diabetes is brought to the hospital complaining of dizziness. Laboratory findings include severe hyperglycemia, ketoacidosis, and a blood pH of 7.15. Which of the following is the most likely complication of insulin therapy in this patient?

Answer 139

Ans: Hypoglycemia Because of the risk of brain damage, the most important complication of insulin therapy is hypoglycemia. The other choices are not common effects of insulin.

Question 140

A 13-year-old boy with type 1 diabetes is brought to the hospital complaining of dizziness. Laboratory findings include severe hyperglycemia, ketoacidosis, and a blood pH of 7.15. Which of the following agents should be administered to achieve rapid control of the severe ketoacidosis in this diabetic boy?

Answer 140

Ans: Crystalline zinc insulin Oral antidiabetic agents (listed in Table 41–1) are inappropriate in this patient because he has insulin-dependent diabetes. He needs a rapid-acting insulin preparation that can be given intravenously (see Figure 41–1).

Question 141

A 24-year-old woman with type 1 diabetes wishes to try tight control of her diabetes to improve her long-term prognosis. Which of the following regimens is most appropriate?

Answer 141

Ans: Morning injections of insulin glargine, supplemented by small amounts of insulin lispro at mealtimes Insulin regimens for tight control usually take the form of establishing a basal level of insulin with a small amount of a long-acting preparation (eg, insulin glargine) and supplementing the insulin levels, when called for by food intake, with short-acting insulin lispro. Less tight control may be achieved with 2 injections of intermediate-acting insulin per day. Because intake of glucose is mainly during the day, long-acting insulins are usually given in the morning, not at night.

Question 142

The PPAR-y receptor that is activated by thiazolidinediones increases tissue sensitivity to insulin by which of the following mechanisms?

Answer 142

Ans: Regulating transcription of genes involved in glucose utilization The PPAR-y receptor belongs to a family of nuclear receptors. When activated, these receptors translocate to the nucleus, where they regulate the transcription of genes encoding proteins involved in the metabolism of carbohydrate and lipids.

Question 143

A 54-year-old obese patient with type 2 diabetes has a history of alcoholism. In this patient, metformin should either be avoided or used with extreme caution because the combination of metformin and ethanol increases the risk of which of the following?

Answer 143

Ans: Lactic acidosis Biguanides, especially the older drug phenformin, have been associated with lactic acidosis. Thus, metformin should be avoided or used with extreme caution in patients with conditions that increase the risk of lactic acidosis, including acute ethanol ingestion.

Question 144

Which of the following is an important effect of insulin?

Answer 144

Ans: Increased glucose transport into cells Insulin lowers serum glucose concentration in part by driving glucose into cells, particularly into muscle cells.

Question 145

Which one of the following drugs promotes the release of endogenous insulin?

Answer 145

Ans: Glipizide Glipizide is a second-generation sulfonylurea that promotes insulin release by closing potassium channels in pancreatic B cells.

Question 146

Which of the following drugs is most likely to cause hypoglycemia when used as monotherapy in the treatment of type 2 diabetes?

Answer 146

Ans: Glyburide The insulin secretagogues, including the sulfonylurea glyburide, can cause hypoglycemia as a result of their ability to increase serum insulin levels. The biguanides, thiazolidinediones, and alpha-glucosidase inhibitors are euglycemics that are unlikely to cause hypoglycemia when used alone.

Question 147

Which of the following drugs is taken during the first part of a meal for the purpose of delaying the absorption of dietary carbohydrates?

Answer 147

Ans: Acarbose To be absorbed, carbohydrates must be converted into monosaccharides by the action of alpha-glucosidase enzymes in the gastrointestinal tract. Acarbose inhibits alpha-glucosidase and, when present during digestion, delays the uptake of carbohydrates.

Question 148

Which of the following patients is most likely to be treated with intravenous glucagon?

Answer 148

Ans: A 62-year-old man with severe bradycardia and hypotension resulting from ingestion of an overdose of atenolol Glucagon acts through cardiac glucagon receptors to stimulate the rate and force of contraction of the heart. Because this bypasses cardiac beta adrenoceptors, glucagon is useful in the treatment of beta-blocker-induced cardiac depression.

Question 149

Which drug accumulates in parietal cell canaliculi and undergoes conversion to a derivative that irreversibly inhibits H+/K+ ATPase?

Answer 149

Ans: Esomeprazole Esomeprazole, the (S) isomer of omeprazole, is a prodrug converting spontaneously in the parietal cell canaliculus to a sulfonamide that irreversibly inactivates the proton pump.

Question 150

A 55-year-old woman with type 1 diabetes of 40 yrs' duration complains of severe bloating and abdominal distress, especially after meals. Evaluation is consistent with diabetic gastroparesis. Which of the following is a prokinetic drug that could be used in this situation?

Answer 150

Ans: Metoclopramide Of the drugs listed, only metoclopramide is considered a prokinetic agent (ie, one that increases propulsive motility in the gut).

Question 151

Which drug is most likely to be useful in the treatment of inflammatory bowel disease?

Answer 151

Ans: Mesalamine Mesalamine is a form of aminosalicylate that releases 5-aminosalicyclic acid in the large intestine and thereby provides a local anti-inflammatory effect that is useful in inflammatory bowel disease.

Question 152

A patient who is taking verapamil for hypertension and angina has become constipated. Which of the following drugs is an osmotic laxative that could be used to treat the patient's constipation?

Answer 152

Ans: Magnesium hydroxide A laxative that mildly stimulates the gut would be most suitable in a patient taking a smooth muscle relaxant drug such as verapamil. By holding water in the intestine, magnesium hydroxide provides additional bulk and stimulates increased contractions.

Question 153

A 34-year-old woman has irritable bowel syndrome with diarrhea that is not responsive to conventional therapies. Despite the small risk of severe constipation and ischemic colitis, the patient decides to begin therapy with alosetron. Alosetron has which of the following receptor actions?

Answer 153

Ans: 5-HT3 receptor antagonist Serotonin plays a major regulatory role in the enteric nervous system, and the potent 5-HT3 receptor antagonist alosetron has shown efficacy in treating women with IBS that is accompanied by diarrhea.

Question 154

A patient is receiving highly emetogenic chemotherapy for metastatic carcinoma. To prevent chemotherapy-induced nausea and vomiting, she is likely to be treated with which of the following?

Answer 154

Ans: Ondansetron The 5-HT3 receptor antagonists are highly effective at preventing chemotherapy-induced nausea and vomiting, which can be a dose-limiting toxicity of anticancer drugs.

Question 155

A 45-year-old man with a duodenal ulcer was treated with a combination of drugs intended to heal the mucosal damage and to eradicate Helicobacter pylori. Which of the following antibacterial drugs is used commonly to eradicate intestinal Helicobacter pylori?

Answer 155

Ans: Clarithromycin The macrolide antibiotic clarithromycin is commonly used in antibiotic regimens designed to treat duodenal ulcers caused by H pylori. The other antibiotics that are used include amoxicillin, tetracycline, and metronidazole. Bismuth also has an antibacterial action.

Question 156

This is a small molecule that polymerizes in stomach acid and coats the ulcer bed, resulting in accelerated healing and reduction of symptoms.

Answer 156

Ans: Sucralfate Sucralfate is a small molecule that polymerizes in stomach acid and forms a protective coat over the ulcer bed.

Question 157

Management of steatorrhea is best accomplished by the use of this agent.

Answer 157

Ans: Pancrelipase Steatorrhea is due to decreased fat absorption as a result of inadequate pancreatic secretion of lipase.

Question 158

On your way to an examination, you experience the vulnerable feeling that an attack of diarrhea is imminent. If you stopped at a drugstore, which one of the following antidiarrheal drugs could you buy without a prescription even though it is related chemically to the strong opioid analgesic meperidine?

Answer 158

Ans: Loperamide Aluminum hydroxide is constipating but is not related chemically to meperidine; magnesium hydroxide is a strong laxative. The 2 antidiarrheal drugs that are structurally related to opioids are diphenoxylate and loperamide. Loperamide is available over-the-counter; diphenoxylate is mixed with atropine alkaloids, and the product (Lomotil, others) requires a prescription.

Question 159

The inducible isoform of nitric oxide synthase (iNOS, isoform 2) is found primarily in which of the following?

Answer 159

Ans: Macrophages The inducible form of NOS is associated with inflammation, and the enzyme is found in highest concentration in macrophages, cells that are particularly involved in inflammation.

Question 160

A molecule that releases nitric oxide in the blood is

Answer 160

Ans: Nitroprusside Nitroprusside is the only molecule in this list that releases NO in the bloodstream.

Question 161

Which of the following is a recognized effect of nitric oxide (NO)?

Answer 161

Ans: Pulmonary vasodilation NO does not cause arrhythmias or constipation. It causes bronchodilation and may hasten graft rejection. NO does cause pulmonary vasodilation.

Question 162

The primary endogenous substrate for the enzyme nitric oxide synthase (NOS) is

Answer 162

Ans: Arginine Arginine is the substrate and citrulline and NO are the products of NOS.

Question 163

Which one of the following is not a nitric oxide donor but causes it to be released from endogenous precursors, resulting in vasodilation?

Answer 163

Ans: Acetylcholine Nitroprusside and organic nitrites (eg, amyl nitrite) and nitrates (eg, nitroglycerin, isosorbide dinitrate, and isosorbide mononitrate) contain NO groups that can be released as NO. Arginine is the normal source of endogenous NO. Acetylcholine stimulates the production of NO from arginine.

Question 164

Which of the following is an approved application for nitric oxide administered as a gas?

Answer 164

Ans: Pulmonary hypertension Thus far, NO gas has been approved for use by inhalation in neonatal hypoxic respiratory failure and adult pulmonary hypertension.