There are two types of calcium channels in cardiovascular system: T-type and L-type. T channels are activated by low voltage whereas L channels are activated by high voltage. T channels take 8 psec to conduct while L channels take 25 psec. T channels are involved in possible growth of cardiac muscles and pacemaker activity of SA node. L channels are involved in Ca+2 induced release, pacemaker activity of SA node and AV conduction. Unlike L channels, T channels have no effect on ventricular and intestinal contractions. In smooth muscles, T channels undergo pharmacomechanical coupling whereas L channels experience excitation-contraction coupling. All calcium-channel blockers inhibit the activity of L channels whereas only mibefradil is known to inhibit the activity of T channels. These prescription medicines are used for lowering blood pressure by reducing the influx of calcium into heart and blood vessels. Calcium channel blockers include amlodipine, felodipine and isradipine. Amlodipine oral is a dihydropyridine which belongs to calcium channel blockers. It is used to treat hypertension, Coronary Artery Disease (CAD) and Angina Pectoris. It is especially used for the treatment of hypertensive patients who also have peripheral vascular disease, asthma and diabetes. Unlike β blockers, Amlodipine does not affect these conditions adversely.The side effects of Amlodipine include swelling of hands, ankles and feet, stomach discomfort, stomach upset, abdominal cramps, drowsiness, flushing, fatigue and tiredness, lightheadedness, nausea and headache. Some severe side effects of Amlodipine include irregular heartbeats, fainting and severe chest pain. Amlodipine has the potential to interct with Simvastatin, CYP3A4 inhibitors (Clarithromycin, Arythromycin, Ketoconazole) and cyclosporine.