Diltiazem is a member of the group of drugs known as Benzothiapines, which are a class of calcium channel blockers, used in the treatment of hypertension, angina pectoris, and some types of arrhythmia. It is a class 3 anti anginal drug. It incites very minimal reflex sympathetic changes.

Diltiazem's is a potent vasodilator, increasing blood flow and variably decreasing the heart rate via strong depression of A-V node conduction.

Diltiazem is metabolized by and acts as an inhibitor of the CYP3A4 enzyme.