Cardiac Drugs
Which of the following drugs slows conduction through the AV node and has a duration of action of 10-20 s? A Adenosine B Amiodarone C Diltiazem D Esmolol E Flecainide F Lidocaine G Mexiletine H Procainamide I Quinidine
A Adenosine
A 25-year-old man is admitted to the emergency department with a brownish cyanotic appearance, marked shortness of breath, and hypotension. He has needle marks in both arms. 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 Explanation: Read carefully! Nitrites, not nitrates, cause methemoglobinemia in adults. Methemoglobinemia is deliberately induced in one of the treatments of cyanide poisoning. Amyl nitrite and isobutyl nitrite, obtained as street drugs, have been heavily used as sex-enhancers. The answer is A.
A 57-year-old woman presents to her primary care physician with a complaint of severe chest pain when she walks uphill in cold weather. The pain disappears when she rests. She has a 40-pack-year history of smoking but her plasma lipids are within the normal range. After evaluation and discussion of treatment options, a decision is made to treat her 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 Explanation: 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.
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 Explanation: Several β blockers, including carvedilol, have been shown to prolong life in heart failure patients even though these drugs may have a negative inotropic action on the heart. Their benefits presumably result from some other β-mediated effect, and at least one other β blocker has failed to show a mortality benefit. The answer is A.
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 Explanation: 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 calcium channels in the colon. 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 Explanation: 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 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 Calcium channel blockers
Alpha1-selective receptor blockers Explanation: 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, orthostatic hypotension may be caused or exacerbated by α1 blockers, eg, prazosin. The answer is B.
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
B Amiodarone Explanation: Amiodarone has the longest half-life of all the antiarrhythmics (weeks). The answer is B.
Which one of the following drugs is associated with clinically useful or physiologically important positive inotropic effects? A Captopril B Dobutamine C Enalapril D Losartan E Nesiritide
B Dobutamine Explanation: 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 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?
B Flecainide Explanation: The drug effect shown in the diagram includes slowing of the upstroke of the AP but no significant change in repolarization or AP duration. This is most typical of group 1C drugs. The answer is B,flecainide.
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 suspected. Which of the following drugs is correctly paired with its ECG effects? A Quinidine: Increased PR and decreased QT intervals B Flecainide: Increased QRS interval C Verapamil: Decreased PR interval D Lidocaine: Decreased QRS and PR interval E Metoprolol: Increased QRS duration
B Flecainide: Increased QRS interval Explanation: All the associations listed are incorrect except flecainide (see Table 14-1). Group 1C drugs block sodium channels but have little effect on K+ and Ca2+ channels. The answer is B.
A 76-year-old retired postal worker with rheumatoid arthritis and chronic heart disease presents with a cardiac arrhythmia and is being considered for treatment with procainamide. She is already receiving an ACE inhibitor, digoxin, and hydrochlorothiazide 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 probable 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 Explanation: 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 no significant β-agonist or β-blocking action. The answer is B.
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 bpm and blood pressure of 135/85 mm Hg. After your patient has been receiving digoxin for 3 weeks, 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 Explanation: 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 54-year-old airline pilot is admitted to the emergency department with chest pain and a rapid heart rhythm. The ECG shows an inferior myocardial infarction and ventricular tachycardia. Amiodarone is ordered. Amiodarone A Decreases PR interval in normal sinus rhythm B Increases action potential duration C Increases contractility D Often causes liver function abnormalities E Reduces resting potential
B Increases action potential duration Explanation: Amiodarone typically decreases contractility only slightly; it prolongs the PR and QRS interval, as well as the QT interval and action potential duration; and it has no effect on the resting potential. Its major toxicity is pulmonary fibrosis, not liver toxicity. The answer is B.
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 Explanation: 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, causing severe renal abnormalities in the fetus. The answer is B.
A 36-year-old woman with a history of poorly controlled thyrotoxicosis has recurrent episodes of tachycardia with severe shortness of breath. During elective surgery to remove her thyroid, she develops a heart rate of 200 bpm with a slightly decreased blood pressure. Which of the following drugs would be most suitable? A Amiodarone B Disopyramide C Esmolol D Quinidine E Verapamil
C Esmolol Explanation: This patient is suffering from a typical perisurgical arrhythmia, exacerbated by her thyroid disorder. Beta blockers are the most effective agents in acute thyrotoxic arrhythmias. While β blockers are used to decrease blood pressure in hypertension, this patient's lowered blood pressure is probably due to the arrhythmia and will normalize when the tachycardia is converted to normal sinus rhythm. Esmolol is a parenteral, rapid-acting β blocker (see Chapter 10). 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 pressure of 220/160 mm Hg 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 Explanation: 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.
A 65-year-old African-American man has long-standing hypertension and moderate heart failure with reduced ejection fraction. His treatment has included furosemide plus digoxin but he continues to have symptoms of shortness of breath and easy fatigue. Which of the following combinations has been shown to be useful in this type of patient? A Digoxin + spironolactone B Furosemide + nesiritide C Hydralazine + isosorbide dinitrate D Isosorbide dinitrate + propranolol E Spironolactone + potassium supplements
C Hydralazine + isosorbide dinitrate Explanation: Chronic congestive failure with hypertension often benefits from a vasodilator that reduces blood pressure and venous pressure. Hydralazine effectively reduces arterial pressure (see Chapter 11) and isosorbide dinitrate is an effective venodilator (see Chapter 12). This combination has been shown to reduce hospitalizations in African Americans with heart failure. The answer is C.
A patient with hypertension and angina is referred for treatment. Metoprolol and verapamil are among the drugs considered. 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 Explanation: Neither β blockers nor calcium channel blockers cause diarrhea. Hypoglycemia is not a common effect of any of the antihypertensive 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. In contrast to verapamil and diltiazem, dihydropyridines do not often cause cardiac depression, probably because they evoke increased sympathetic outflow as a result of their dominant vascular effects. The answer is C.
A 60-year-old woman comes to the emergency department with atypical chest pain. Her ECG reveals ventricular tachycardia with rare normal sinus beats, and ST-segment elevation. Troponin C levels are markedly increased, suggesting myocardial damage. A diagnosis of myocardial infarction is made, and the woman is admitted to the cardiac intensive care unit. Her arrhythmia will probably be treated initially with A Adenosine B Digoxin C Lidocaine D Quinidine E Verapamil
C Lidocaine Explanation: Lidocaine has limited applications as an antiarrhythmic drug, but emergency treatment of myocardial infarction arrhythmias is one of the most important. Procainamide or amiodarone are used as alternative drugs in this situation. Lidocaine is also useful in digoxin-induced arrhythmias. After recovery from the acute phase of a myocardial infarction, β blockers are used for 2 years or more to prevent sudden death arrhythmias. The answer is C.
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 bpm 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 a late transmembrane sodium current 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 Explanation: Digitalis does not decrease calcium uptake by the sarcoplasmic reticulum or increase sodium current; 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 by inhibiting Na+/K+ transport by the ATPase sodium pump and indirectly altering Na+/Ca2+ exchange. The answer is D.
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 Explanation: 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. 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 Explanation: The effects of β blockers and nitrates on heart size, force, venous tone, and heart rate are opposite. The effects of β blockers and calcium channel blockers on heart size, force, and rate are similar. The answer is D.
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 Increases calcium excretion in the urine
D Decreases calcium influx into smooth muscle Explanation: 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 Ca2+ 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. The answer is D.
A 57-year-old woman presents to her primary care physician with a complaint of severe chest pain when she walks uphill in cold weather. The pain disappears when she rests. She has a 40-pack-year history of smoking but her plasma lipids are within the normal range. After evaluation and discussion of treatment options, a decision is made to treat her with nitroglycerin. In advising the patient about the adverse effects she 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 due to reduced colonic activity 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 Explanation: 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 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 Explanation: Chronic, intolerable cough is an important adverse effect of captopril and other ACE inhibitors. It may be associated with increased bradykinin levels because ARBs are not as frequently associated with cough. The ACE inhibitors 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.
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 Explanation: 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 57-year-old woman presents to her primary care physician with a complaint of severe chest pain when she walks uphill in cold weather. The pain disappears when she rests. She has a 40-pack-year history of smoking but her plasma lipids are within the normal range. After evaluation and discussion of treatment options, a decision is made to treat her 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 Explanation: Nitroglycerinincreases 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 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 Explanation: 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, may cause severe tachycardia that must be controlled with β blockers. The answer is D.
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 Explanation: 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.
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 mm Hg, and pulse is 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 Explanation: Both drugs cause venodilation and reduce venous return sufficiently to cause some degree of postural hypotension. Bradycardia, lupus, and urinary retention occur with neither of them, but prazosin has been used to relieve urinary retention in men with prostatic hyperplasia. While this patient has a high body mass index of 29.9, weight gain is not a risk with either drug. The answer is D.
Which of the following drugs increases the plasma levels of endogenous BNP and is combined with another agent that blocks angiotensin receptors? A Furosemide B Losartan C Nesiritide D Sacubitril E Spironolactone
D Sacubitril Explanation: Furosemide has no significant effect on peptide metabolism and does not block AT1 receptors. Losartan blocks AT1 receptors but has no effect on peptide metabolism. Nesiritide is a synthetic BNP and does not block AT1 receptors. Spironolactone blocks the aldosterone receptor in the kidney. Only sacubitril/valsartan has the combined effect listed in the stem of this question. The answer is D.
A 76-year-old retired postal worker with rheumatoid arthritis and chronic heart disease presents with a cardiac arrhythmia and is being considered for treatment with procainamide. She is already receiving an ACE inhibitor, digoxin, and hydrochlorothiazide 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 Adenosine C Nitroprusside D Potassium chloride E Sodium lactate
E Sodium lactate Explanation: The most effective therapy for procainamide (and quinidine) toxicity appears to be concentrated sodium lactate. This drug may (1) increase sodium current by increasing the sodium ion gradient and (2) reduce drug-receptor binding by alkalinizing the tissue. The answer is E.
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 Furosemide D Nitroprusside E Spironolactone
E Spironolactone Explanation: Of the drugs listed, only spironolactone has been shown to reduce mortality in this highly lethal disease. Digoxin, furosemide, and nitroprusside are used in the management of symptoms. The answer is E.
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. Which of the following drugs would be most suitable for prophylaxis of future episodes of acute AV nodal tachycardia? A Adenosine B Amiodarone C Flecainide D Propranolol E Verapamil
E Verapamil Explanation: Calcium channel blockers are effective in both treating and preventing supraventricular AV nodal tachycardias. They are orally active and have a duration of action of several hours. Adenosine is very effective in most acute nodal tachycardias and is less toxic because of its extremely short duration of action. However, it is not useful for chronic prophylaxis because it must be given IV and has a very short duration of action. The answer is E.
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 Explanation: 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 57-year-old woman presents to her primary care physician with a complaint of severe chest pain when she walks uphill in cold weather. The pain disappears when she rests. She has a 40-pack-year history of smoking but her plasma lipids are within the normal range. After evaluation and discussion of treatment options, a decision is made to treat her with nitroglycerin. One year later, the patient returns complaining that her nitroglycerin works well when she takes it for an acute attack but that she 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 Explanation: 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. Thus, nitrites, sublingual nitrates, and esmolol are of no value in prophylaxis. The answer is E.
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 Explanation: Sildenafil inhibits phosphodiesterase 5, an enzyme that inactivates cGMP. The nitrates (via nitric oxide) increase the synthesis of cGMP. This combination is synergistic. The answer is F.
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 Nesiritide J Spironolactone
H Furosemide Explanation: In both acute and chronic failure and systolic (HFrEF) and diastolic heart failure (HFpEF), the initial treatment of choice is usually furosemide. The answer is H.
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 Explanation: The two agents in this list that act via a nitric oxide mechanism 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.
