CVS Flashcards
A 32-year-old woman with hypertension wishes to become pregnant. Her physician informs her that she will have to switch to another antihypertensive drug. Which of the following drugs is absolutely contraindicated in pregnancy?
(A) Atenolol
(B) Losartan
(C) Methyldopa
(D) Nifedipine
(E) Propranolol
(B) Losartan
Methyldopa is often recommended in pregnant patients because it has a good safety record. Calcium channel blockers (choice D) and β blockers (choices A and E) are not contraindicated. In contrast, ACE inhibitors and ARBs (choice B) have been shown to be teratogenic.
A patient is admitted to the emergency department with severe tachycardia after a drug overdose. His family reports that he has been depressed about his hypertension. Which one of the following drugs increases the heart rate in a dose-dependent manner?
(A) Captopril
(B) Hydrochlorothiazide
(C) Losartan
(D) Minoxidil
(E) Verapamil
(D) Minoxidil
ACE inhibitors (choice A), ARBs (choice C), and diuretics (choice B) do not significantly increase heart rate. Although dihydropyridine calcium channel blockers do not usually reduce rate markedly (and may increase it), verapamil (choice E) and diltiazem do inhibit the sinoatrial node and predictably decrease rate. Other direct vasodilators (choice D) regularly increase heart rate, and minoxidil, a very efficacious vasodilator, causes severe tachycardia that must be controlled with β blockers
Which one of the following is characteristic of nifedipine treatment in patients with essential hypertension?
(A) Competitively blocks angiotensin II at its receptor
(B) Decreases calcium efflux from skeletal muscle
(C) Decreases renin concentration in the blood
(D) Decreases calcium influx into smooth muscle
(E) Decreases calcium flux into the urine
(D) Decreases calcium influx into smooth muscle
Nifedipine is a prototype L-type calcium channel blocker and lowers blood pressure by reducing calcium influx into vascular smooth muscle. It has no effect on angiotensin-converting enzyme. Calcium efflux from skeletal muscle cells does not involve the L-type Ca channel. The plasma renin level may increase as a result of the compensatory response to reduced blood pressure. Calcium channel blockers have negligible effects on urine calcium.
A 73-year-old man with a history of a recent change in his treatment for moderately severe hypertension is brought to the emergency department because of a fall at home. Which of the following drug groups is most likely to cause postural hypotension and thus an increased risk of falls?
(A) ACE inhibitors
(B) Alpha1-selective receptor blockers
(C) Arteriolar dilators
(D) Beta1-selective receptor blockers
(E) Nonselective β blockers
(B) Alpha1-selective receptor blockers
Drug-induced postural (orthostatic) hypotension is usually due to venous pooling or excessive diuresis and inadequate blood volume. Venous pooling is normally prevented by α-receptor activation in vascular smooth muscle; thus, ortho
static hypotension is caused or exacerbated by α1 blockers, eg, prazosin.
A significant number of patients started on ACE inhibitor therapy for hypertension are intolerant and must be switched to a different class of drug. What is the most common manifestation of this intolerance?
(A) Angioedema
(B) Glaucoma
(C) Headache
(D) Incessant cough
(E) Ventricular arrhythmias
(D) Incessant cough
Chronic, intolerable cough is an important adverse effect of captopril and other ACE inhibitors. It may be reduced or prevented by prior administration of aspirin. These drugs are very commonly used in hypertensive diabetic patients because of their proven benefits in reducing diabetic renal damage. The ACE inhibitors are not associated with glaucoma; angioedema is not as common as cough; and headache and arrhythmias are rare. The answer is D.
Which one of the following is a significant unwanted effect of the drug named?
(A) Constipation with verapamil
(B) Heart failure with hydralazine
(C) Hemolytic anemia with atenolol
(D) Hypokalemia with aliskiren
(E) Lupus-like syndrome with hydrochlorothiazide
(A) Constipation with verapamil
Hydralazine (choice B) is sometimes used in heart failure. Beta blockers (choice C) are not associated with hematologic abnormalities, but methyldopa is. The thiazide diuretics (choice E) often cause mild hyperglycemia, hyperuricemia, and hyperlipidemia but not lupus; hydralazine is associated with a lupus-like syndrome. Aliskiren (choice D) and other inhibitors of the renin-angiotensin-aldosterone system may cause hyperkalemia, not hypokalemia. Verapamil (choice A) often causes constipation, probably by blocking L-type cal
cium channels in the colon. The answer is A.
Comparison of prazosin with atenolol shows that
(A) Both decrease heart rate
(B) Both increase cardiac output
(C) Both increase renin secretion
(D) Both increase sympathetic outflow from the CNS
(E) Both produce orthostatic hypotension
(D) Both** increase sympathetic outflow from the CNS**
Atenolol, but not prazosin, may decrease heart rate (choice A). Prazosin—but not atenolol—may increase cardiac output, a compensatory effect (choice B). Prazosin may increase renin output (a compensatory response), but β blockers inhibit its release by the kidney (choice C). By reducing blood pressure, both may increase central sympathetic outflow (a compensa
tory response). Beta blockers do not cause orthostatic hypo
tension. The answer is D.
A patient with hypertension and angina is referred for treat
ment. Metoprolol and verapamil are among the drugs con
sidered. Both metoprolol and verapamil are associated with which one of the following?
(A) Diarrhea
(B) Hypoglycemia
(C) Increased PR interval
(D) Tachycardia
(E) Thyrotoxicosis
(C) Increased PR interval
Neither β blockers nor calcium channel blockers cause diarrhea. Hypoglycemia is not a common effect of any of the antihyper
tensive drugs. Thyroid disorders are not associated with either drug group. However, calcium blockers, especially verapamil and diltiazem, and β blockers are associated with depression of calcium-dependent processes in the heart, for example, contractility, heart rate, and atrioventricular conduction. Therefore, bradycardia and increased PR interval may be expected. The dihydropyridines do not often cause cardiac depression, prob
ably because they evoke increased sympathetic outflow as a result of their dominant vascular effects. The answer is C.
A 45-year-old man is brought to the emergency department with mental obtundation. He is found to have a blood pres sure of 220/160 and retinal hemorrhages. Which one of the following is used in severe hypertensive emergencies, is short-acting, acts on a G protein-coupled receptor, and must be given by intravenous infusion?
(A) Aliskiren
(B) Captopril
(C) Fenoldopam
(D) Hydralazine
(E) Losartan
(F) Metoprolol
(G) Nitroprusside
(H) Prazosin
(I) Propranolol
(C) Fenoldopam
Fenoldopam, nitroprusside, and propranolol are the drugs in the list that have been used in hypertensive emergencies. Fenoldopam and nitroprusside are used by infusion only, but nitroprusside releases nitric oxide, which acts on intracellular guanylyl cyclase. The answer is C
Which of the following is very short-acting and acts by releasing nitric oxide?
(A) Atenolol
(B) Captopril
(C) Diltiazem
(D) Fenoldopam
(E) Hydrochlorothiazide
(F) Losartan
(G) Minoxidil
(H) Nitroprusside
(I) Prazosin
(H) Nitroprusside
The two agents in this list that act via a nitric oxide mecha
nism are hydralazine and nitroprusside (see Table 11–2). However, hydralazine has a duration of action of hours, whereas nitroprusside acts for seconds to minutes and must be given by intravenous infusion. The answer is H.
A 60-year-old man presents to his primary care physician with a complaint of severe chest pain when he walks uphill to his home in cold weather. The pain disappears when he rests. After evaluation and discussion of treatment options, a decision is made to treat him with nitroglycerin.
Which of the following is a common direct or reflex effect of nitroglycerin?
(A) Decreased heart rate
(B) Decreased venous capacitance
(C) Increased afterload
(D) Increased cardiac force
(E) Increased diastolic myocardial fiber tension
(D) Increased cardiac force
Nitroglycerin increases heart rate and venous capacitance and decreases afterload and diastolic fiber tension.
It increases cardiac contractile force because the decrease in blood pressure evokes a compensatory increase in sympathetic discharge.
The answer is D.
A 60-year-old man presents to his primary care physician with a complaint of severe chest pain when he walks uphill to his home in cold weather. The pain disappears when he rests. After evaluation and discussion of treatment options, a decision is made to treat him with nitroglycerin.
In advising the patient about the adverse effects he may notice, you point out that nitroglycerin in moderate doses often produces certain symptoms. Which of the following effects might occur due to the mechanism listed?
(A) Constipation
(B) Dizziness due to reduced cardiac force of contraction
(C) Diuresis due to sympathetic discharge
(D) Headache due to meningeal vasodilation
(E) Hypertension due to reflex tachycardia
(D) Headache due to meningeal vasodilation
The nitrates relax many types of smooth muscle, but the effect on motility in the colon is insignificant. Nitroglycerin causes hypotension as a result of arterial and venous dilation. Dilation of arteries in the meninges has no effect on central nervous system function but does cause headache. The answer is D.
A 60-year-old man presents to his primary care physician with a complaint of severe chest pain when he walks uphill to his home in cold weather. The pain disappears when he rests. After evaluation and discussion of treatment options, a decision is made to treat him with nitroglycerin.
One year later, the patient returns complaining that his nitroglycerin works well when he takes it for an acute attack but that he is now having more frequent attacks and would like something to prevent them. Useful drugs for the prophylaxis of angina of effort include
(A) Amyl nitrite
(B) Esmolol
(C) Sublingual isosorbide dinitrate
(D) Sublingual nitroglycerin
(E) Verapamil
(E) Verapamil
The calcium channel blockers and the β blockers are generally effective in reducing the number of attacks of angina of effort, and most have durations of 4–8 h. Oral and transdermal nitrates have similar or longer durations. Amyl nitrite and the sublingual nitrates have short durations of action (a few minutes to 30 min). Esmolol (an intravenous β blocker) must be given intravenously and also has a very short duration of action. These drugs are of no value in prophylaxis. The answer is E.
A 60-year-old man presents to his primary care physician with a complaint of severe chest pain when he walks uphill to his home in cold weather. The pain disappears when he rests. After evaluation and discussion of treatment options, a decision is made to treat him with nitroglycerin.
If a β blocker were to be used for prophylaxis in this patient, what is the most probable mechanism of action in angina?
(A) Block of exercise-induced tachycardia
(B) Decreased end-diastolic ventricular volume
(C) Increased double product
(D) Increased cardiac force
(E) Decreased ventricular ejection time
(A) Block of exercise-induced tachycardia
Propranolol blocks tachycardia but has none of the other effects listed. Only revascularization increases double product; drugs that decrease cardiac work increase exercise time by decreasing double product. The answer is A.
A new 60-year-old patient presents to the medical clinic with hypertension and angina. He is 1.8 meters tall with a waist measurement of 1.1 m. Weight is 97 kg. Blood pressure is 150/95 and pulse 85. In considering adverse effects of possible drugs for these conditions, you note that an adverse effect that nitroglycerin and prazosin have in common is
(A) Bradycardia
(B) Impaired sexual function
(C) Lupus erythematosus syndrome
(D) Orthostatic hypotension
(E) Weight gain
(D) Orthostatic hypotension
Both drugs cause venodilation and reduce venous return sufficiently to cause some degree of postural hypotension. Bradycardia, lupus, weight gain, and urinary retention occur with neither of them, but prazosin has been used to relieve urinary retention in men with prostatic hyperplasia. The answer is D.
A man is admitted to the emergency department with a brownish cyanotic appearance, marked shortness of breath, and hypotension. Which of the following is most likely to cause methemoglobinemia?
(A) Amyl nitrite
(B) Isosorbide dinitrate
(C) Isosorbide mononitrate
(D) Nitroglycerin
(E) Sodium cyanide
(A) Amyl nitrite
Read carefully! Nitrites, not nitrates, cause methemoglobinemia in adults. Methemoglobinemia is delibrately induced in one of the treatments of cyanide poisoning. The answer is A.
Another patient is admitted to the emergency department after a drug overdose. He is noted to have hypotension and severe bradycardia. He has been receiving therapy for hypertension and angina. Which of the following drugs in high doses causes bradycardia?
(A) Amlodipine
(B) Isosorbide dinitrate
(C) Nitroglycerin
(D) Prazosin
(E) Verapamil
(E) Verapamil
Isosorbide dinitrate (like all the nitrates) and prazosin can cause reflex tachycardia. Amlodipine, a dihydropyridine calcium channel blocker, causes much more vasodilation than cardiac depression and may also cause reflex tachycardia. Verapamil typically slows heart rate and high doses may cause severe bradycardia. The answer is E.
A 45-year-old woman with hyperlipidemia and frequent migraine headaches develops angina of effort. Which of the following is relatively contraindicated because of her migraines?
(A) Amlodipine
(B) Diltiazem
(C) Metoprolol
(D) Nitroglycerin
(E) Verapamil
(D) Nitroglycerin
Acute migraine headache is associated with vasodilation of meningeal arteries. Of the drugs listed, only nitroglycerin is commonly associated with headache. In fact, calcium channel blockers and β blockers have been used with some success as prophylaxis for migraine. The answer is D.
When nitrates are used in combination with other drugs for the treatment of angina, which one of the following combinations results in additive effects on the variable specified?
(A) Beta blockers and nitrates on end-diastolic cardiac size
(B) Beta blockers and nitrates on heart rate
(C) Beta blockers and nitrates on venous tone
(D) Calcium channel blockers and β blockers on cardiac force
(E) Calcium channel blockers and nitrates on heart rate
(D) Calcium channel blockers and β blockers on cardiac force
The effects of β blockers (or calcium channel blockers) and nitrates on heart size, force, venous tone, and heart rate are opposite. The effects of β blockers and calcium channel blockers on the variables specified here are the same. The answer is D.
Certain drugs can cause severe hypotension when combined with nitrates. Which of the following interacts with nitroglycerin by inhibiting the metabolism of cGMP?
(A) Atenolol
(B) Hydralazine
(C) Isosorbide mononitrate
(D) Nifedipine
(E) Ranolazine
(F) Sildenafil
(G) Terbutaline
(F) Sildenafil
Sildenafil inhibits phosphodiesterase 5, an enzyme that inactivates cGMP. The nitrates (via nitric oxide) increase the synthe
sis of cGMP. This combination is synergistic. The answer is F.
A 73-year-old man with an inadequate response to other drugs is to receive digoxin for chronic heart failure. He is in normal sinus rhythm with a heart rate of 88 and blood pressure of 135/85 mm Hg.
Which of the following is the best documented mechanism of beneficial action of cardiac glycosides?
(A) A decrease in calcium uptake by the sarcoplasmic reticulum
(B) An increase in ATP synthesis
(C) A modification of the actin molecule
(D) An increase in systolic cytoplasmic calcium levels
(E) A block of cardiac β adrenoceptors
(D) An increase in systolic cytoplasmic calcium levels
Digitalis does not decrease calcium uptake by the sarcoplasmic reticulum or increase ATP synthesis; it does not modify actin. Cardiac adrenoceptors are not affected. The most accurate description of digitalis’s mechanism in this list is that it increases systolic cytoplasmic calcium indirectly by inhibiting Na+/K+ ATPase and altering Na/Ca exchange. The answer is D.
After your patient has been receiving digoxin for 3 wk, he presents to the emergency department with an arrhythmia. Which one of the following is most likely to contribute to the arrhythmogenic effect of digoxin?
(A) Increased parasympathetic discharge
(B) Increased intracellular calcium
(C) Decreased sympathetic discharge
(D) Decreased intracellular ATP
(E) Increased extracellular potassium
(B) Increased intracellular calcium
The effects of digitalis include increased vagal action on the heart (not arrhythmogenic) and increased intracellular calcium, including calcium overload, the most important cause of toxicity. Decreased sympathetic discharge and increased extracellular potassium and magnesium reduce digitalis arrhythmogenesis. The answer is B.
A patient who has been taking digoxin for several years for atrial fibrillation and chronic heart failure is about to receive atropine for another condition. A common effect of digoxin (at therapeutic blood levels) that can be almost entirely blocked by atropine is
(A) Decreased appetite
(B) Headaches
(C) Increased atrial contractility
(D) Increased PR interval on ECG
(E) Tachycardia
(D) Increased PR interval on ECG
The parasympathomimetic effects of digitalis can be blocked by muscarinic blockers such as atropine. The only parasympathomimetic effect in the list provided is increased PR interval, a manifestation of slowed AV conduction. The answer is D.
A 65-year-old woman has been admitted to the coronary care unit with a left ventricular myocardial infarction. She develops acute severe heart failure with marked pulmonary edema, but no evidence of peripheral edema. Which one of the following drugs would be most useful?
(A) Digoxin
(B) Furosemide
(C) Minoxidil
(D) Propranolol
(E) Spironolactone
(B) Furosemide
Acute severe congestive failure with pulmonary edema often requires a vasodilator that reduces intravascular pressures in the lungs. Furosemide has such vasodilating actions in the context of acute failure. Pulmonary edema also involves a shift of fluid from the intravascular compartment to the lungs. Minoxidil would decrease arterial pressure and increase the heart rate excessively. Digoxin has a slow onset of action and lacks vasodilating effects. Spironolactone is useful in chronic failure but not in acute pulmonary edema. Pulmonary vasodilation and removal of edema fluid by diuresis are accomplished by furosemide. The answer is B.
A 72-year-old woman has long-standing heart failure. Which one of the following drugs has been shown to reduce mortality in chronic heart failure?
(A) Atenolol
(B) Digoxin
(C) Dobutamine
(D) Furosemide
(E) Spironolactone
(E) Spironolactone
Of the drugs listed, only spironolactone has been shown to reduce mortality in this highly lethal disease. Digoxin, dobutamine, and furosemide are used in the management of symptoms. The answer is E.
Which row in the following table correctly shows the major effects of full therapeutic doses of digoxin on the AV node and the ECG?
Digitalis increases the AV node refractory period—a parasympa
thomimetic action. Its effects on the ventricles include shortened action potential and QT interval, and a change in repolarization with flattening or inversion of the T wave. The answer is B.
Which one of the following drugs is associated with clinically useful or physiologically important positive inotropic effect?
(A) Captopril
(B) Dobutamine
(C) Enalapril
(D) Losartan
(E) Nesiritide
(B) Dobutamine
Although they are extremely useful in heart failure, ACE inhibitors (eg, captopril, enalapril), and angiotensin receptor blockers (ARBs, eg, losartan) have no positive inotropic effect on the heart. Nesiritide is a vasodilator with diuretic effects and renal toxicity. Dobutamine is a β1-selective adrenoceptor agonist. The answer is B.
A 68-year-old man with a history of chronic heart failure goes on vacation and abandons his low-salt diet. Three days later, he develops severe shortness of breath and is admitted to the local hospital emergency department with significant pulmonary edema. The first-line drug of choice in most cases of acute decompensation in patients with chronic heart failure is
(A) Atenolol
(B) Captopril
(C) Carvedilol
(D) Digoxin
(E) Diltiazem
(F) Dobutamine
(G) Enalapril
(H) Furosemide
(I) Metoprolol
(J) Spironolactone
(H) Furosemide
In both acute and chronic failure and systolic and diastolic heart failure, the initial treatment of choice is usually furosemide. The answer is H.
Which of the following has been shown to prolong life in patients with chronic congestive failure in spite of having a negative inotropic effect on cardiac contractility?
(A) Carvedilol
(B) Digoxin
(C) Dobutamine
(D) Enalapril
(E) Furosemide
(A) Carvedilol
Several β blockers, including carvedilol, have been shown to prolong life in heart failure patients even though these drugs have a negative inotropic action on the heart. Their benefits presumably result from some other effect, and at least one β blocker has failed to show a mortality benefit. The answer is A.
A 5-year-old child was vomiting and was brought to the emergency department with sinus arrest and a ventricular rate of 35 bpm. An empty bottle of his uncle’s digoxin was found where he was playing. Which of the following is the drug of choice in treating a severe overdose of digoxin?
(A) Digoxin antibodies
(B) Lidocaine infusion
(C) Magnesium infusion
(D) Phenytoin by mouth
(E) Potassium by mouth
(A) Digoxin antibodies
The drug of choice in severe, massive overdose with any cardiac glycoside is digoxin antibody, Digibind. The other drugs listed are used in moderate overdosage associated with increased automaticity. The answer is A.
A 76-year-old patient with rheumatoid arthri- tis and chronic heart disease is being considered for treatment with procainamide. She is already receiving digoxin, hydrochlo- rothiazide, and potassium supplements for her cardiac condition.
In deciding on a treatment regimen with procainamide for this patient, which of the following statements is most correct?
(A) A possible drug interaction with digoxin suggests that digoxin blood levels should be obtained before and after starting procainamide
(B) Hyperkalemia should be avoided to reduce the likelihood of procainamide toxicity
(C) Procainamide cannot be used if the patient has asthma because it has a β-blocking effect
(D) Procainamide cannot be used if the patient has angina because it has a β-agonist effect
(E) Procainamide is not active by the oral route
(B) Hyperkalemia should be avoided to reduce the likelihood of procainamide toxicity
76-year-old patient with rheumatoid arthritis and chronic heart disease is being considered for treatment with procainamide. She is already receiving digoxin, hydrochlorothiazide, and potassium supplements for her cardiac condition.
If this patient should take an overdose and manifest severe acute procainamide toxicity with markedly prolonged QRS, which of the following should be given immediately?
(A) A calcium chelator such as EDTA
(B) Digitalis
(C) Nitroprusside
(D) Potassium chloride
(E) Sodium lactate
(E) Sodium lactate
A 57-year-old man is admitted to the emergency depart- ment with chest pain and a fast irregular heart rhythm. The ECG shows an inferior myocardial infarction and ventricular tachycardia. Lidocaine is ordered. When used as an antiarrhythmic drug, lidocaine typically
(A) Increases action potential duration
(B) Increases contractility
(C) Increases PR interval
(D) Reduces abnormal automaticity
(E) Reduces resting potential
(D) Reduces abnormal automaticity
A 36-year-old woman with a history of poorly controlled thy- rotoxicosis has recurrent episodes of tachycardia with severe shortness of breath. When she is admitted to the emergency department with one of these episodes, which of the following drugs would be most suitable?
(A) Amiodarone
(B) Disopyramide
(C) Esmolol
(D) Quinidine
(E) Verapamil
(C) Esmolol
A 16-year-old girl has paroxysmal attacks of rapid heart rate with palpitations and shortness of breath. These episodes occasionally terminate spontaneously but often require a visit to the emergency department of the local hospital. Her ECG during these episodes reveals an AV nodal tachycardia. The antiarrhythmic of choice in most cases of acute AV nodal tachycardia is
(A) Adenosine
(B) Amiodarone
(C) Flecainide
(D) Propranolol
(E) Verapamil
(A) Adenosine
A55-year old man is admitted to the emergency department and is found to have an abnormal ECG. Overdose of an anti- arrhythmic drug is considered. Which of the following drugs is correctly paired with its ECG effects?
(A) Quinidine: Increased PR and decreased QT intervals
(B) Flecainide: Increased PR, QRS, and QT intervals (C) Verapamil: Increased PR interval
(D) Lidocaine: Decreased QRS and PR interval
(E) Metoprolol: Increased QRS duration
(C) Verapamil: Increased PR interval
A 60-year-old man comes to the emergency department with severe chest pain. ECG reveals ventricular tachycardia with occasional normal sinus beats, and ST-segment changes suggestive of ischemia. A diagnosis of myocardial infarction is made, and the man is admitted to the cardiac intensive care unit. His arrhythmia should be treated immediately with
(A) Adenosine
(B) Digoxin
(C) Lidocaine
(D) Quinidine
(E) Verapamil
(C) Lidocaine
Lidocaine has limited applications as an antiarrhythmic drug, but emergency treatment of myocardial infarction arrhythmias is one of the most important. Lidocaine is also useful in digoxin-induced arrhythmias. After recovery from the acute phase of a myocardial infarction, β blockers are used for 2 yr or more to prevent sudden death arrhythmias. The answer is C
Which of the following drugs slows conduction through the AV node and has its primary action directly on L-type calcium channels?
(A) Adenosine
(B) Amiodarone
(C) Diltiazem
(D) Esmolol
(E) Flecainide
(F) Lidocaine
(G) Mexiletine
(H) Procainamide
(I) Quinidine
(C) Diltiazem
Diltiazem is the calcium channel blocker in this list. (Beta blockers also slow AV conduction but have much smaller effects on calcium channels.) The answer is C.
When working in outlying areas, this 62-year-old rancher is away from his house for 12–14 h at a time. He has an arrhythmia that requires chronic therapy. Which of the following has the longest half-life of all antiarrhythmic drugs?
(A) Adenosine
(B) Amiodarone
(C) Disopyramide
(D) Esmolol
(E) Flecainide
(F) Lidocaine
(G) Mexiletine
(H) Procainamide
(I) Quinidine
(J) Verapamil
Amiodarone
Amiodarone has the longest half-life of all the antiarrhythmics (weeks). The answer is B.
A drug was tested in the electrophysiology laboratory to determine its effects on the cardiac action potential in normal ventricular cells. The results are shown in the diagram.
Which of the following drugs does this agent most resemble? (A) Adenosine
(B) Flecainide
(C) Mexiletine
(D) Procainamide (E) Verapamil
The drug effect shown in the diagram includes slowing of the upstroke of the AP but no significant change in repolariza- tion or AP duration. This is most typical of group 1C drugs. The answer is B, flecainide.
A 70-year-old retired businessman is admitted with a history of recurrent heart failure and metabolic derangements. He has marked peripheral edema and metabolic alkalosis. Which of the following drugs is most appropriate for the treatment of his edema?
(A) Acetazolamide
(B) Digoxin
(C) Dobutamine
(D) Eplerenone
(E) Hydrochlorothiazide
(A) Acetazolamide
Although acetazolamide is rarely used in heart failure, car- bonic anhydrase inhibitors are quite valuable in patients with edema and metabolic alkalosis. The high bicarbonate levels in these patients make them particularly susceptible to the action of carbonic anhydrase inhibitors. Digoxin is useful in chronic systolic failure but is not first-line therapy. Dobu- tamine is appropriate only when diuresis has already been accomplished in severe acute failure. Hydrochlorothiazide and spironolactone are not adequate for first-line therapy of edema in failure. The answer is A.
A 50-year-old man has a history of frequent episodes of renal colic with calcium-containing renal stones. A careful workup indicates that he has a defect in proximal tubular calcium reabsorption, which results in high concentrations of calcium salts in the tubular urine. The most useful diuretic agent in the treatment of recurrent calcium stones is
(A) Chlorthalidone
B) Diazoxide
(C) Ethacrynic acid
(D) Mannitol
(E) Spironolactone
(A) Chlorthalidone
The thiazides are useful in the prevention of calcium stones because these drugs reduce tubular calcium concentration, probably by increasing passive proximal tubular and distal convoluted tubule reabsorption of calcium. In contrast, the loop agents (choice C) facilitate calcium excretion. Diazoxide is a thiazide-like vasodilator molecule but has no diuretic action; in fact, it may cause sodium retention. It is used in hypertension and insulinoma (see Chapter 11). The answer is A
Which of the following is an important effect of chronic therapy with loop diuretics?
(A) Decreased urinary excretion of calcium
(B) Elevation of blood pressure
(C) Elevation of pulmonary vascular pressure
(D) Metabolic alkalosis
(E) Teratogenic action in pregnancy
(D) Metabolic alkalosis
Loop diuretics increase urinary calcium excretion and decrease blood pressure (in hypertension) and pulmonary vascular pres- sure (in congestive heart failure). They have no recognized tera- togenic action. They cause metabolic alkalosis (Table 15–1). Loop diuretics also cause ototoxicity. The answer is D.
Which drug is correctly associated with its actions in the following table? (+ indicates increase and – indicates decrease.)
D
Acetazolamide causes metabolic acidosis. Furosemide causes a marked increase in sodium and a moderate increase in potassium excretion. Thiazides cause alkalosis and a greater increase in sodium than potassium excretion. Mannitol causes a small increase in both sodium and potassium excre- tion and no change in body pH. Spironolactone causes the changes indicated. The answer is D.
Which of the following diuretics would be most useful in the acute treatment of a comatose patient with traumatic brain injury and cerebral edema?
(A) Acetazolamide
(B) Amiloride
(C) Chlorthalidone
(D) Furosemide
(E) Mannitol
(E) Mannitol
An osmotic agent is needed to remove water from the cells of the edematous brain and reduce intracranial pressure rapidly. The answer is E.
The above graph shows the plasma concentration of free warfarin as a function of time for a patient who was treated with 2 other agents, drugs B and C, on a daily basis at constant dosage starting at the times shown. Which of the following is the most likely explanation for the observed changes in warfarin concentration?
(A) Drug B displaces warfarin from plasma proteins; drug C displaces warfarin from tissue-binding sites
(B) Drug B inhibits hepatic metabolism of warfarin; drug C displaces drug B from tissue-binding sites
(C) Drug B stimulates hepatic metabolism of warfarin; drug C displaces warfarin from plasma protein
(D) Drug B increases renal clearance of warfarin; drug C inhibits hepatic metabolism of drug B
(C) Drug B stimulates hepatic metabolism of warfarin; drug C displaces warfarin from plasma protein
A drug that increases metabolism (clearance) of the antico- agulant lowers the steady-state plasma concentration (both free and bound forms), whereas one that displaces the antico- agulant increases the plasma level of the free form only until elimination of the drug has again lowered it to the steady- state level. The answer is C.
A 46-year-old woman 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 patient received?
(A) Colestipol
(B) Ezetimibe
(C) Gemfibrozil
(D) Lovastatin
(E) Niacin
(E) Niacin
This patient presents with striking hypertriglyceridemia, elevated VLDL cholesterol, and depressed HDL cholesterol. Six months after drug treatment was initiated, her triglyceride and VLDL cholesterol have dropped dramatically and her 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. The answer is E.
