Amlodipine is a dihydropyridine L-type calcium channel blocker that selectively inhibits calcium influx in cardiac and vascular smooth muscle. Acting as a vasodilator, amlodipine reduces blood pressure by relaxing the smooth muscle in the arterial wall, decreasing total peripheral resistance. It inhibits calcium-induced contractions in depolarized rat aorta with an IC50 value of 1.9 nM, displaying a slow rate of association and dissociation in isolated vascular and cardiac tissues. When used in combination with the angiotensin receptor blocker olmesartan, amlopidine has been shown to potentiate antihypertensive activity. Amlodipine also demonstrates actions independent of L-type calcium channel blockade by regulating membrane fluidity and cholesterol deposition, stimulating nitric oxide production, acting as an antioxidant, and regulating matrix deposition.
