Pharmacology of major drug classes used - nitrates and antianginals

Overview

Nitrates and other antianginal classes relieve angina by reducing myocardial oxygen demand and/or improving coronary supply, via distinct mechanisms depending on the drug

Nitrates remain first-line for acute anginal symptom relief; other antianginal classes are used for prophylaxis/refractory symptoms

Drug	Mechanism	Key use
Nitrates (GTN, isosorbide)	NO donor -> venodilation (predominant, reduces preload) + some coronary vasodilation	Acute relief (sublingual GTN), prophylaxis
Nicorandil	K+ channel opener + nitrate-like activity	Second-line antianginal; rare but serious complication - GI/skin ulceration
Ranolazine	Inhibits late sodium current - reduces intracellular Ca2+ overload	Refractory angina, no significant haemodynamic effect (useful when BP/HR limit other agents)
Ivabradine	Inhibits the If ("funny") current in the SA node - pure heart rate reduction	Angina/HF with a contraindication to or insufficient effect from beta-blockers, sinus rhythm only

Nitrate tolerance develops with continuous exposure - a nitrate-free interval (typically overnight) is required to maintain efficacy with regular dosing
Sildenafil (and other PDE5 inhibitors) + nitrates -> severe, potentially fatal hypotension - an absolute contraindication; always ask about erectile dysfunction medication use before prescribing/administering nitrates
Ivabradine requires sinus rhythm (ineffective/inappropriate in AF) and can cause visual phenomena (phosphenes) as a class-specific side effect

Stable angina, acute coronary syndrome (GTN for symptom relief), heart failure (ivabradine in HFrEF with elevated resting heart rate)

These agents treat symptoms/ischaemia but (with the exception of some HF-specific uses of ivabradine) do not modify the underlying atherosclerotic disease process - risk factor management and statins remain the disease-modifying therapy

5 more sections, plus exam facts

Premium unlocks every note across every specialty, and the full exam fact library behind it.