This document discusses different types of angina and drugs used to treat them. It describes stable angina, which is predictable and relieved by rest. Unstable angina occurs with less exertion and may happen at rest. Prinzmetal angina typically happens at rest and is caused by coronary artery spasms. Common drugs to treat angina include nitrates like nitroglycerin, beta blockers, calcium channel blockers, and aspirin. Nitroglycerin works by dilating blood vessels to increase blood flow and reduce oxygen demands on the heart. Beta blockers prevent reflex heart rate increases from nitrates and both drug classes reduce oxygen needs.