Noun | 1. | diltiazem - a calcium blocker (trade name Cardizem) used in treating hypertension or angina or heart failure calcium blocker, calcium-channel blocker - any of a class of drugs that block the flow of the electrolyte calcium (either in nerve cell conduction or smooth muscle contraction of the heart); has been used in the treatment of angina or arrhythmia or hypertension or migraine |