Calcium channel antagonists inhibit the entry of calcium by blocking the L-type of calcium channels. This decreases calcium current and calcium entry into cardiac and vascular smooth muscle cells resulting in vasodilation and decreased myocardial contraction. Nifedipine is a potent vasodilator while verapamil has prominent myocardial depressant effects. CCBs are used in angina pectoris, hypertension, arrhythmias, peripheral vascular diseases and verapamil is also used in migraine.