Katzung & Trevor's Pharmacology Examination & Board Review - 10E - Part III (Cardiovascular Drugs)

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) Hydrochlorothiazide (E) Spironolactone

(A) Acetazolamide Although acetazolamide is rarely used in heart failure, carbonic 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. Dobutamine is appropriate only when diuresis has already been accomplished in severe acute failure. Hydrochlorothiazide and spirono- lactone are not adequate for first-line therapy of edema in failure.

A graduate student is planning to make a high-altitude climb in South America while on vacation. He will not have time to acclimate slowly to altitude. A drug that is useful in preventing high-altitude sickness is: (A) Acetazolamide (B) Amiloride (C) Demeclocycline (D) Desmopressin (E) Ethacrynic acid

(A) Acetazolamide Carbonic anhydrase inhibitors are useful in the prevention of altitude sickness.

A 60-year-old patient complains of paresthesias and occasional nausea associated with one of her drugs. She is found to have hyperchloremic metabolic acidosis. She is probably taking (A) Acetazolamide for glaucoma (B) Amiloride for edema associated with aldosteronism (C) Furosemide for severe hypertension and heart failure (D) Hydrochlorothiazide for hypertension (E) Mannitol for cerebral edema

(A) Acetazolamide for glaucoma Paresthesias and gastrointestinal distress are common adverse effects of acetazolamide, especially when it is taken chronically, as in glaucoma. The observation that the patient has metabolic acidosis also suggests the use of acetazolamide.

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 Calcium channel blockers are effective in supraventricular AV nodal tachycardias. However, adenosine is just as effective in most acute nodal tachycardias and is less toxic because of its extremely short duration of action.

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 methemoglobin- emia in adults. Methemoglobinemia is deliberately induced in one of the treatments of cyanide poisoning.

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.

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.

A 5-year-old child is 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.

A 73-year-old man with a history of falling at home is found to have moderately severe hypertension. Which of the follow- ing drug groups is most likely to cause postural hypotension and thus an increased risk of falls? (A) ACE inhibitors (B) Alpha-receptor blockers (C) Arteriolar dilators (D) Beta1-selective receptor blockers (E) Nonselective β blockers

(B) Alpha-receptor blockers Postural (orthostatic) hypotension is usually due to venous pooling. Venous pooling is normally prevented by α-receptor activation. (Postural hypotension may also occur in patients with hypovolemia owing to excessive diuretic treatment.)

When working in outlying fields, this 62-year-old farmer 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

(B) Amiodarone Amiodarone has the longest half-life of all the antiarrhythmics (weeks).

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) Captopril (C) Methyldopa (D) Prazosin (E) Propranolol

(B) Captopril Methyldopa is often recommended in pregnant patients because it has a good safety record. Alpha (choice D) and β blockers (choices A and E) are not contraindicated. In con- trast, ACE inhibitors (choice B) and ARBs have been shown to be teratogenic.

Which one of the following is characteristic of captopril treatment in patients with essential hypertension? (A) Competitively blocks angiotensin II at its receptor (B) Decreases angiotensin II concentration in the blood (C) Decreases renin concentration in the blood (D) Increases sodium and decreases potassium in the blood (E) Decreases sodium and increases potassium in the urine

(B) Decreases angiotensin II concentration in the blood Converting enzyme inhibitors act on the enzyme, not on the angiotensin receptor. The plasma renin level may increase as a result of the compensatory response to reduced angiotensin II. ACE inhibitors increase blood potassium and urine sodium.

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 nitro- glycerin 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) Diltiazem (C) Esmolol (D) Sublingual isosorbide dinitrate (E) Sublingual nitroglycerin

(B) Diltiazem 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, the sublingual nitrates, and esmolol (an intravenous β blocker) have short durations of action and are of no value in prophylaxis.

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.

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 or weight gain. 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 vaso- dilation and removal of edema fluid by diuresis are accomplished by furosemide.

A 62-year-old man with advanced prostate cancer is admit- ted to the emergency department with mental obtundation. An electrolyte panel shows a serum calcium of 16.5 (normal ∼8.5-10.5 mg/dL). Which of the following therapies would be most useful in the management of severe hypercalcemia? (A) Acetazolamide plus saline infusion (B) Furosemide plus saline infusion (C) Hydrochlorothiazide plus saline infusion (D) Mannitol plus saline infusion (E) Spironolactone plus saline infusion

(B) Furosemide plus saline infusion Diuretic therapy of hypercalcemia requires a reduction in calcium reabsorption in the thick ascending limb, an effect of loop diuretics. However, a loop diuretic alone would reduce blood volume around the remaining calcium so that serum calcium would not decrease appropriately. Therefore, saline infusion should accompany the loop diuretic.

A 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. 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 has a duration of action of 36-40 h (E) Procainamide is not active by the oral route

(B) Hyperkalemia should be avoided to reduce the likelihood of procainamide toxicity Hyperkalemia facilitates procainamide toxicity. Procainamide is active by the oral route and has a duration of action of 2-4 h (in the prompt-release form). Procainamide has no significant documented interaction with digoxin and little or no β-blocking action.

A 73-year-old man with an inadequate response to other drugs is to receive digoxin for heart failure. 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.

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) Calcium channel blockers and β blockers on cardiac force (D) Beta blockers and nitrates on venous tone (E) Calcium channel blockers and nitrates on heart rate

(C) Calcium channel blockers and β blockers on cardiac force The effects of βblockers (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 are the same.

A 58-year-old woman with lung cancer has abnormally low serum osmolality. A drug that increases the formation of dilute urine and is used to treat SIADH is (A) Acetazolamide (B) Amiloride (C) Conivaptan (D) Desmopressin (E) Ethacrynic acid (F) Furosemide (G) Hydrochlorothiazide (H) Mannitol (I) Spironolactone (J) Triamterene

(C) Conivaptan Inability to form dilute urine in the fully hydrated condition is characteristic of SIADH. Antagonists of ADH are needed to treat this condition.

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.)

A 36-year-old woman with a history of poorly controlled thyrotoxicosis 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 Beta blockers are the most effective agents in acute thyrotoxic arrhythmias. Esmolol is a parenteral, rapid-acting β blocker.

A 45-year-old man is brought to the emergency department with mental obtundation. He is found to have a blood pressure of 220/160 and retinal hemorrhages. Which one of the follow- ing 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) Nifedipine (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.

Which one of the following is a significant unwanted effect of the drug named? (A) Heart failure with hydralazine (B) Hemolytic anemia with atenolol (C) Fetal damage with losartan (D) Lupus-like syndrome with hydrochlorothiazide (E) Tachycardia with verapamil

(C) Fetal damage with losartan Hydralazine (choice A) is sometimes used in heart failure. Beta blockers (choice B) are not associated with hematologic abnormalities, but methyldopa is. The thiazide diuretics (choice D) often cause mild hyperglycemia, hyperuricemia, and hyperlipidemia but not lupus; hydralazine is associated with a lupus-like syndrome. Verapamil (choice E) often causes bradycardia, not tachycardia. ARBs (choice C) may cause damage to the fetal kidney, and they are contraindicated in pregnancy.

A 70-year-old woman is admitted to the emergency depart- ment because of a "fainting spell" at home. She appears to have suffered no trauma from her fall, but her blood pressure is 120/60 when lying down and 60/20 when she sits up. Neurologic examination and an ECG are within normal limits when she is lying down. Questioning reveals that she has recently started taking "water pills" (diuretics) for a heart condition. Which of the following drugs is the most likely cause of her fainting spell? (A) Acetazolamide (B) Amiloride (C) Furosemide (D) Hydrochlorothiazide (E) Spironolactone

(C) Furosemide The case history suggests that the syncope (fainting) is associated with diuretic use. Complications of diuretics that can result in syncope include both postural hypotension (which this patient exhibits) due to excessive reduction of blood volume and arrhythmias due to excessive potassium loss. Potassium wasting is more common with thiazides (because of their long duration of action), but these drugs rarely cause reduction of blood volume sufficient to result in orthostatic hypotension.

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) Acetazolamide (B) Furosemide (C) Hydrochlorothiazide (D) Mannitol (E) Spironolactone

(C) Hydrochlorothiazide 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 facilitate calcium excretion.

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) Diarrhea (B) Glaucoma (C) Incessant cough (D) Lupus-like syndrome (E) Vomiting

(C) Incessant cough Chronic, intolerable cough is an important adverse effect of captopril and other ACE inhibitors. It may be relieved 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 do not cause glaucoma or gastrointestinal disturbances.

A patient with hypertension is to receive a calcium channel blocker. Verapamil is associated with which one of the following? (A) Diarrhea (B) Hypoglycemia (C) Increased PR interval (D) Tachycardia (E) Thyrotoxicosis

(C) Increased PR interval Calcium channel blockers do not cause diarrhea and are sometimes associated with constipation, probably through inhibition of calcium influx in intestinal smooth muscle. Hypoglycemia is not a common effect of any of the anti- hypertensive drugs. Thyroid disorders are not associated with calcium blockers. However, calcium blockers, especially verapamil and diltiazem, 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, probably because they evoke increased sympathetic outflow as a result of their dominant vascular effects.

Another patient is admitted to the emergency department after a drug overdose. He is noted to have hypotension and severe tachycardia. He has been receiving therapy for hyper- tension and angina. Which of the following drugs often causes tachycardia? (A) Clonidine (B) Diltiazem (C) Isosorbide dinitrate (D) Propranolol (E) Verapamil

(C) Isosorbide dinitrate Isosorbide dinitrate (like all the nitrates) can cause reflex tachycardia, but all the other drugs listed here slow heart rate.

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 yrs or more to prevent sudden death arrhythmias.

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) Minoxidil (D) Prazosin (E) Verapamil

(C) Minoxidil Neither ACE inhibitors (choice A) nor diuretics (choice B) significantly increase heart rate. Although dihydropyridine calcium channel blockers do not usually reduce rate markedly (and may increase it), verapamil and diltiazem do inhibit the sinoatrial node and predictably decrease rate. Direct vasodila- tors (choice C) and α blockers (choice D) regularly increase heart rate but minoxidil, a very efficacious vasodilator causes severe tachycardia that must be controlled with β blockers.

A 55-year-old man is admitted to the emergency department and is found to have an abnormal ECG. Overdose of an antiarrhythmic 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 All the associations listed are incorrect except verapamil (see Table 14-1). This group 4 drug increases PR interval and has little effect on the other ECG variables.

A 73-year-old man with an inadequate response to other drugs is to receive digoxin for heart failure. 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 blocked. 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.

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 compensatory response). Beta blockers do not cause orthostatic hypotension.

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) Apnea due to cranial vasodilation (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 Nitroglycerin causes hypotension as a result of arterial and venous dilation. Dilation of arteries in the head has no effect on central nervous system function but does cause headache.

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 parasympa- thomimetic effect in the list provided is increased PR interval, representing slowing of AV conduction.

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 pres- sure evokes a compensatory increase in sympathetic discharge.

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.

A new 60-year-old patient presents to the medical clinic with hypertension and angina. 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) Throbbing headache

(D) Orthostatic hypotension Both drugs cause venodilation and reduce venous return sufficiently to cause some degree of postural hypotension. Throbbing headache is a problem only with the nitrates, and bradycardia and lupus with neither of them.

A drug was tested in the electrophysiology laboratory to deter- mine its effects on the cardiac action potential in 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

(D) Procainamide The drug effect shown in the diagram includes slowing of the upstroke of the AP and prolongation of repolarization or AP duration. This is most typical of group 1A drugs.

A 57-year-old man is admitted to the emergency department with an irregular heart rate. 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 Lidocaine reduces automaticity in the ventricles; the drug does not alter resting potential or AP duration and does not increase contractility.

Which of the following diuretics would be most useful in the acute treatment of a comatose patient with brain injury and cerebral edema? (A) Acetazolamide (B) Amiloride (C) Ethacrynic acid (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.

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 acidosis (E) Ototoxicity

(E) Ototoxicity Loop diuretics increase urinary calcium excretion and decrease blood pressure (in hypertension) and pulmonary vascular pressure. They cause metabolic alkalosis. Loop diuretics also cause ototoxicity.

A 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 The most effective therapy for procainamide toxicity appears to be concentrated sodium lactate. This drug may (1) increase sodium current by increasing the ionic gradient and (2) reduce drug-receptor binding by alkalinizing the tissue.

An 82-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.

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 synthesis of cGMP. This combination is synergistic.

A 38-year-old man who has been running a marathon col- lapses and is brought to the emergency department. He is found to have a left ventricular myocardial infarction and heart failure with significant pulmonary edema. The first-line drug of choice in most cases of 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 systolic and diastolic heart failure, the initial treatment of choice is usually furosemide.

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.

Which row in the following table correctly shows the major effects of full therapeutic doses of digoxin on the AV node and the ECG? A, B, C, D, or E

The answer is B. Digitalis increases the AV node refractory period—a parasympathomimetic 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.

Which drug is correctly associated with its actions in the following table? (+ indicates increase and - indicates decrease.) A, B, C, D, or E

The answer is 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 excretion and no change in body pH. Spironolactone causes the changes indicated.