Diltiazem is in a group of drugs called calcium channel blockers. It works by relaxing the muscles of your heart and blood vessels. Diltiazem is used to treat hypertension (high blood pressure), angina (chest pain), and certain heart rhythm disorders. Diltiazem may also be used for purposes not listed in this medication guide.
Cardizem CD is a 24 hour extended release calcium channel blocking capsule. It relaxes cardiac and arterial muscles by decreasing the amount of calcium that is able to enter these muscle groups. This effect brings down blood pressure and heart rate. Cardizem CD must be prescribed by a doctor.