Besylon Mechanism of Action

Pharmacology: Pharmacodynamics: Mechanism of Action: Amlodipine is a dihydropyridine calcium-channel blocker. It is a peripheral and coronary vasodilator but unlike the calcium-channel blockers Verapamil or Diltiazem, has little or no effect on cardiac conduction and negative inotropic activity is rarely seen at therapeutic doses. Administration results primarily in vasodilation, with reduced peripheral resistance, blood pressure and afterload, increased coronary blood flow and a reflex increase in heart rate. This in turn results in an increase in myocardial oxygen supply and cardiac output. It has no antiarrhythmic activity. Amlodipine maybe even more selective than Nifedipine for vascular smooth muscle. Most of the dihydropyridine calcium-channel blockers are chiral compounds used as racemic mixtures.
Pharmacokinetics: Amlodipine is well absorbed following oral administration with peak blood concentrations occurring after 6 to 12 hours. The bioavailability is about 60 to 65%. Amlodipine is reported to be about 97.5% bound to plasma proteins. It has a prolonged terminal elimination half-life of 35 to 50 hours and steady-state plasma concentrations are not achieved until after 7 to 8 days of administration. Amlodipine is extensively metabolized in the liver; metabolites are mostly excreted in urine together with less than 10% of a dose as unchanged drug.