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Chapter 51. Drugs for Angina Pectoris. Drugs for Angina Pectoris. Angina pectoris Sudden pain beneath the sternum, often radiating to left shoulder and arm Oxygen supply to the heart is insufficient to meet oxygen demand Two goals of angina drug therapy
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Chapter 51 Drugs for Angina Pectoris
Drugs for Angina Pectoris • Angina pectoris • Sudden pain beneath the sternum, often radiating to left shoulder and arm • Oxygen supply to the heart is insufficient to meet oxygen demand • Two goals of angina drug therapy • Prevention of myocardial infarction and death • Prevention of myocardial ischemia and anginal pain
Drugs for Angina Pectoris • Three families of antianginal agents • Organic nitrates • Nitroglycerin • Beta blockers • Example: propranolol • Calcium channel blockers • Example: verapamil • Ranolazine • A newer drug with limited indications • Can be combined with other drugs
Determinants of Cardiac Oxygen Demand and Supply Oxygen demand Heart rate Myocardial contractility Intramyocardial wall tension (preload/afterload) Oxygen supply Myocardial blood flow Myocardial perfusion only in diastole
Angina Pectoris: Pathophysiology and Treatment • Three forms of angina pectoris • Chronic stable angina (exertional angina) • Variant angina (Prinzmetal’s or vasospastic angina) • Unstable angina
Chronic Stable Angina (Exertional) • Pathophysiology • Emotional excitement • Large meals • Cold exposure • Coronary artery disease (CAD) • Treatment strategy • Increase cardiac oxygen supply • Decrease oxygen demand
Chronic Stable Angina (Exertional) • Therapeutic agents (provide symptomatic relief) • Organic nitrates • Beta blockers • Calcium channel blockers • Ranolazine • Nondrug therapy • Avoid factors that can precipitate angina • Decrease risk factors
Fig.51–1. Effect of exertion on the balance between oxygen supply and oxygen demand in the healthy heart and the heart with CAD.
Variant Angina (Prinzmetal’s: Vasospastic) • Pathophysiology • Coronary artery spasm • Treatment strategy • Increasing cardiac oxygen supply • Therapeutic agents • Calcium channel blockers • Organic nitrates
Unstable Angina: Medical Emergency • Severe CAD complicated by vasospasm • Pathophysiology • Symptoms of angina at rest • New-onset exertional angina • Intensification of existing angina • Treatment strategy • Maintain oxygen supply • Decrease oxygen demand
Unstable Angina: Medical Emergency • Therapeutic agents for acute management • Anti-ischemic therapy • Antiplatelet therapy • Anticoagulant therapy
Anti-ischemic Therapy • Nitroglycerin • Beta blocker • Supplemental O2 • IV morphine • ACE inhibitor
Antiplatelet/Anticoagulant Therapy • Aspirin (indefinitely) • Clopidogrel (Plavix) • Abciximab (ReoPro) • Eptifibatide (Integrilin) • Anticoagulant therapy • Subcutaneous LMW heparin or IV unfractionated heparin LMW = low-molecular-weight.
Organic Nitrates • Nitroglycerin • Stable and variant angina • Vasodilator • Adverse effects • Headache • Orthostatic hypotension • Reflex tachycardia
Organic Nitrates: Nitroglycerin • Vasodilator actions • Mechanism of antianginal effects • Stable angina • Variant angina • Pharmacokinetics • Adverse effects
Organic Nitrates: Nitroglycerin • Drug interactions • Hypotensive drugs • Phophodiesterase type 5 inhibitors • Beta blockers, verapamil, and diltiazem
Organic Nitrates: Nitroglycerin • Tolerance • Can develop rapidly • Cross-tolerance to all other nitrates • To minimize, use the lowest effective dose • Long-acting formulas: 8 drug-free hours per day
Organic Nitrates: Nitroglycerin • Preparations and routes of administration • Sublingual tablets • Sustained-release oral capsules • Transdermal delivery systems • Translingual spray • Topical ointment • Intravenous infusion
Organic Nitrates: Nitroglycerin • Long-acting preparations • Discontinue slowly • Therapeutic uses summarized • Acute anginal therapy • Sustained anginal therapy • IV for perioperative control of blood pressure and treatment of heart failure with MI, unstable angina, and uncontrolled exacerbations of chronic angina
Organic Nitrates: Other • Isosorbidemononitrate and isosorbidedinitrate • Actions identical to those of nitroglycerin • Used for angina, taken orally, produce headache, hypotension, and reflex tachycardia • Amyl nitrite • Ultrashort-acting agent used to treat acute episodes of angina pectoris
Beta Blockers • Decrease cardiac oxygen demand • Propranolol, metoprolol • Adverse effects • Bradycardia • Decreased atrioventricular (AV) conduction • Reduction of contractility • Asthmatic effects • Use with caution in patients with diabetes • Insomnia • Depression • Bizarre dreams • Sexual dysfunction
Calcium Channel Blockers • Verapamil, diltiazem, nifedipine • Block calcium channels in vascular smooth muscle (VSM) • Used for stable and variant angina • Adverse effects • Dilation of peripheral arterioles • Reflex tachycardia • Hypotension • Beta blockers • Bradycardia • Heart failure • AV block
Ranolazine • Belongs to first new class of antianginal agents approved in more than 25 years • Benefits modest and greater in men than in women • Does not reduce heart rate, blood pressure, or vascular resistance • Can prolong QT; multiple drug interactions • Exact mechanism unknown • Not a first-line therapy; combine with first-line agents for inadequate response to other first-line medications
Revascularization Therapy • Coronary artery bypass graft (CABG) surgery • Percutaneoustransluminal coronary angioplasty (PTCA) • Comparison of CABG surgery with percutaneous coronary intervention (PCI)
Drugs Used to Prevent Myocardial Infarction and Death • Antiplatelet drugs • Cholesterol-lowering drugs • Angiotensin-converting enzyme (ACE) inhibitors • Antianginal agents
Reduction of Risk Factors • Smoking • High cholesterol • Hypertension • Diabetes • Physical inactivity
Management of Variant Angina • Treatment of vasospastic angina • Initial therapy • Calcium channel blocker or long-acting nitrate • If either of these alone is inadequate, add a nitrate • If combination fails, CABG may be indicated • Beta blockers are not effective with vasospastic angina