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CHAPTER 24. Antianginal Drugs. Angina Pectoris. Chest pain due to coronary artery disease (CAD) and myocardial ischemia Exertional angina (pain) usually occurs during physical exertion or stress Vasospastic angina may occur at any time and is due to coronary artery vasospasm
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CHAPTER 24 Antianginal Drugs
Angina Pectoris • Chest pain due to coronary artery disease (CAD) and myocardial ischemia • Exertional angina (pain) usually occurs during physical exertion or stress • Vasospastic angina may occur at any time and is due to coronary artery vasospasm • Untreated CAD and angina pectoris may lead to myocardial infarction and death
Drugs Used to Treat CAD • Nitrites and nitrates • Beta adrenergic blocking drugs • Calcium antagonists, also referred to as calcium channel blockers
Nitrites and Nitrates • Drugs stimulate the formation of nitric oxide, a potent vasodilator of blood vessels • Vasodilation of veins and arteries decreases cardiac work and cardiac oxygen consumption to relieve the pain of myocardial ischemia • Nitrites and nitrates may cause a drop in blood pressure and reflex tachycardia • These drugs can be used to treat acute attacks of angina or to prevent anginal attacks
Drugs Used to Relieve Acute Attacks of Angina • Amyl nitrite is administered by inhalation from a glass ampule, it has a sudden onset and duration of action of 5–10 minutes • Nitroglycerin is administered as sublingual tablets which require a few minutes for onset and may last 30–45 minutes • Nitroglycerin may also be administered intravenously in more severe cases
Drugs Used Prophylactically to Prevent Angina Pectoris • Nitroglycerin can be administered as an ointment, as extended release tablets or capsules, or by transdermal patch • Isosorbide and pentaerythritol nitrates are usually administered orally 3–4 times/day depending on the frequency of anginal attacks
Adverse Effects of Nitrites and Nitrates • Vasomotor flushing, dizziness, and headache are common due to vasodilation • When administered for acute angina, the sudden onset of vasodilation may cause hypotension, fainting, and tachycardia • Patients should be seated when inhaling or taking these drugs sublingually
Beta Adrenergic Blockers • Sympathetic beta receptor stimulation of the heart increases heart rate, force of contraction, and oxygen consumption • Blockade of beta receptors decreases cardiac work and cardiac oxygen demand • Beta blockers are used prophylactically to prevent angina and can be combined with other antianginal drugs • The pharmacology of the beta blockers was presented in chapter 6 • Egg: propranolol (Inderal)
Calcium Antagonists • Drugs block influx of calcium ions into the heart and blood vessels to vasodilate and lower blood pressure, cardiac work, and oxygen demand • Verapamil and diltiazem act on both the heart and blood vessels • Nifedipine and other calcium antagonists act mainly to dilate arterial blood vessels • Calcium antagonists are used prophylactically to prevent angina • Adverse effects include excessive vasodilation, hypotension, cutaneous flushing, and headache • Egg: Verapamil (Calan)