Antianginal Drugs

Aspirin irreversibly inhibits cyclooxygenase-1, the enzyme platelets use to produce thromboxane A2, a potent activator of platelet aggregation and vasoconstrictor. Because mature platelets lack a nucleus and cannot synthesize new enzyme, a single aspirin dose disables cyclooxygenase-1 for the entire remaining lifespan of each affected platelet, producing an antiplatelet effect that substantially outlasts the drug itself. Low-dose aspirin is the standard antiplatelet agent for nearly all patients with established coronary artery disease.

Clopidogrel works through an entirely different mechanism: it irreversibly blocks the platelet P2Y12 receptor, the receptor through which adenosine diphosphate normally promotes platelet aggregation. Because aspirin and clopidogrel act on two separate activation pathways, combining them produces a more complete blockade of platelet aggregation than either drug alone, which is the pharmacological rationale for dual antiplatelet therapy after an acute coronary event. In stable coronary artery disease without a recent acute event, clopidogrel is mainly used as an alternative to aspirin in patients who cannot tolerate it.

Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers reduce the activity of the renin-angiotensin-aldosterone system, lowering blood pressure and reducing the harmful cardiac and vascular remodeling that chronic angiotensin II exposure promotes. These agents are particularly valuable in patients with reduced ejection fraction, diabetes, or chronic kidney disease alongside their coronary artery disease, conditions in which renin-angiotensin-aldosterone system activity is especially harmful.

The complete regimen for a patient with stable coronary artery disease, combining antiplatelet therapy, a statin, a renin-angiotensin system inhibitor, and antianginal drugs as needed for symptoms, is collectively known as optimal medical therapy. A foundational finding in modern cardiology is that, in patients with stable coronary artery disease, optimal medical therapy alone produces outcomes for death and myocardial infarction that are comparable to adding percutaneous coronary intervention, the procedure used to open a narrowed coronary artery with a stent.

Revascularization does provide meaningfully better and faster relief of angina symptoms than medical therapy alone. The clinical implication is that every patient with stable coronary artery disease deserves a full trial of optimal medical therapy before revascularization is pursued for hard outcomes such as death or myocardial infarction, while recognizing that symptom relief and quality of life remain legitimate reasons to pursue revascularization in patients who remain limited despite medical therapy.