Beta-blocking drugs

A. Classification and Mechanism of Action: These drugs are described in detail in Chapter 10. All beta-blockers are effective in the prophylaxis of atherosclerotic angina attacks.

B. Effects: Actions include both beneficial effects (decreased heart rate, cardiac force, blood pressure) and detrimental effects (increased heart size, longer ejection period) (Table 12-3). Like the nitrates and calcium channel blockers, the beta-blockers reduce the double product.

C. Clinical Use: Beta-blockers are used only for prophylactic therapy of angina; they are of no value in ah acute attack. They are effective in preventing exercise-induced angina but are ineffective against the vasospastic form. The combination of beta-blockers with nitrates is useful because the undesirable compensatory effects evoked by the nitrates (tachycardia and increased cardiac force) are prevented or reduced by beta blockade. (See Table 12-3.)

D. Toxicity: See Chapter 10.

Nonpharmacologic therapy

Myocardial revascularization by coronary artery bypass grafting (CABG) or percutaneous transluminal coronary angioplasty (PTCA) are important therapies in severe angina. These are the only methods capable of consistently increasing coronary flow in atherosclerotic angina and increasing the double product.

Drug list

The following drugs are important members of the group discussed in this chapter. Prototypes should be learned in detail; features of the major variants should be known well enough so that the variants can be distinguished from prototypes and from each other; the other significant agents should be recognized as belonging to a specific subclass.

Subclass	Prototype	Major Variants	Other Significant Agents
Nitrates	Nitroglycerin	Different dosage forms (sublingual, oral, transdermal)	Isosorbide dinitrate, amyl nitrite
Calcium channel blockers	Nifedipine Verapamil Diltiazem	Nimodipine	Bepridil, mibefradil
Beta-blockers	Propranolol	See Chapter 10

Vasodilators & the Treatment of Angina questions

DIRECTIONS: Each of the numbered items or incomplete statements in this section is followed by answers or by completions of the statement. Select the ONE lettered answer or completion that is BEST in each case.

Items 1-3: Mr Green, 60 years old, has severe chest pain when he attempts to carry parcels upstairs to his apartment. The pain rapidly disappears when he rests. A decision is made to treat Mr Green with nitroglycerin.

1. Nitroglycerin, either directly or through reflexes, results in all of the following EXCEPT

(A) Increased heart rate

(B) Decreased cardiac force

(C) Increased venous capacitance

(D) Decreased intramyocardial fiber tension

(E) Decreased afterload

2. In advising Mr Green about the adverse effects he may notice, you point out that nitroglycerin in moderate doses often produces certain symptoms. These toxicities result from all of the following EXCEPT

(A) Meningeal vasodilation

(B) Reflex tachycardia

(C) Increased cardiac force

(D) Methemoglobinemia

(E) Sympathetic discharge

3. Two years later, Mr Green returns complaining that his nitroglycerin works well when he takes it for an acute attack, but he is having frequent attacks now and would like something to prevent them. Effective drugs for the prophylaxis of angina of effort include all of the following EXCEPT

(A) Transdermal nitroglycerin

(B) Amyl nitrite

(C) Diltiazem

(D) Nadolol

(E) Oral isosorbide dinitrate

4. The antianginal effect of propranolol may be attributed to all of the following EXCEPT

(A) Block of exercise-induced tachycardia

(B) Reduced resting heart rate

(C) Decreased cardiac force

(D) Increased end-diastolic ventricular volume

(E) Decreased systolic fiber tension

5. The major common determinant of myocardial oxygen consumption is

(A) Blood volume

(B) Cardiac output

(C) Diastolic blood pressure

(D) Heart rate

(E) Myocardial fiber tension

6. A new patient presents with severe hypertension and angina. You are considering therapeutic options for her. In considering adverse effects, you note that an adverse effect that nitroglycerin, guanethidine, and ganglion blockers have in common is

(A) Bradycardia

(B) Impaired sexual function

(C) Lupus erythematosus syndrome

(D) Orthostatic hypotension

(E) Throbbing headache

7. Epidemiologic surveys suggest that, in the past, workers exposed to high levels of organic nitrates in the workplace had

(A) A high incidence of methemoglobinemia on the job

(B) An increased incidence of angina at work as compared to at home

(C) A high incidence of cyanide poisoning in the workplace

(D) An increased incidence of headaches on Mondays as compared to other days

(E) All of the above

8. A patient is admitted to the emergency department with marked tachycardia. She has been receiving therapy for hypertension and angina. A drug that often causes tachycardia when given in ordinary doses is

(A) Isosorbide dinitrate

(B) Verapamil

(C) Guanethidine

(D) Propranolol

(E) Diltiazem

9. A patient being treated for another condition complains that whenever he takes that medication, his angina become worse. Drugs that may precipitate angina when used for other indications include all of the following EXCEPT

(A) Hydralazine

(B) Terbutaline

(C) Isoproterenol

(D) Reserpine

(E) Amphetamine

10. When using nitrates in combination with other drugs for the treatment of angina,

(A) The actions of beta-blockers and nitrates on end-diastolic cardiac size are additive

(B) The actions of calcium channel blockers and nitrates on cardiac force are antagonistic

(C) The actions of calcium channel blockers and nitrates on vascular tone are antagonistic

(D) The actions of beta-blockers and nitrates on heart rate are additive

(E) The actions of calcium channel blockers and beta-blockers on cardiac force are antagonistic

DIRECTIONS (Items 11—15): Each set of matching questions in this section consists of a list of three to twenty-six lettered options (some of which may be figures) followed by several numbered items. For each numbered item, select the ONE lettered option that is MOST closely associated with it. Each lettered option may be selected once, more than once, or not at all.

(A) Amyl nitrite

(B) Hydralazine

(C) Isosorbide mononitrate

(D) Nifedipine

(E) Nimodipine

(F) Nitroglycerin (sublingual)

(G) Nitroglycerin (transdermal)

(H) Propranolol

(I) Terbutaline

(J) Verapamil

11. A drug that is approved for the treatment of hemorrhagic stroke

12. A drug used by inhalation; very rapid onset but brief effect (2-5 minutes)

13. A drug capable of maintaining blood levels for 24 hours, but useful therapeutic effects last only about 10 hours

14. An antihypertensive vasodilator drug that lacks a direct effect on autonomic receptors but may provoke anginal attacks

15. An active metabolite of another drug and an active antianginal drug for oral administration in its own right