Amlodipine is a dihydropyridine calcium antagonist (calcium ion antagonist or slow-channel blocker) that inhibits the transmembrane influx of calcium ions into vascular smooth muscle. The contraction of the cardiac and vascular smooth muscle are dependent upon the movement of extracellular calcium ions into these cells through specific ion channels. Amlodipine inhibits calcium ion influx across cell membrane selectively, with a greater effect on vascular smooth muscle cells that on cardiac muscle cells. Amlodipine also exerts vasodilation to the peripheral arteries by direct action on the vascular smooth muscle causing a reduction in peripheral vascular resistance and blood pressure.

Amlodipine is well absorbed following oral administration with peak blood concentration occurring after 6 to 12 hours. The bioavailability is about 60%-65%. Amlodipine is reported to be about 97.5% bound to plasma proteins. It has prolonged terminal elimination half-life of 35 to 50 hours and steady state plasma concentrations are not achieved until 7 to 8 days of administration. Amlodipine is extensively metabolized in the liver; metabolites are mostly excreted in the urine together with less than 10% of a dose with unchanged drug.

Indications:

Amlodipine is used in the management of hypertension ang prophylaxis of angina pectoris. It may be used in combination with other antihypertensive and antianginal agents