Definition

A type of drug that keeps calcium from entering the muscle cells of the heart and blood vessels. This causes the blood vessels to relax and widen, which allows the blood to flow more easily and lowers blood pressure. Some calcium antagonists may also slow the heartbeat. Calcium antagonists are used to treat high blood pressure, chest pain (angina), abnormal heartbeat (arrhythmia), and several other conditions. Also called calcium channel blocker.