Amlopine Mechanism of Action

Pharmacodynamics: Mechanism of Action: Amlodipine besylate is a long-acting dihydropyridine calcium channel blocker that exerts its effect by blocking the transmembrane influx of calcium ions into cardiac and vascular smooth muscles. It also reduces peripheral vascular resistance and lowers blood pressure by causing a direct vasodilation in the peripheral arteries of the vascular smooth muscle. Its therapeutic effect on vasospastic angina is through inhibition of coronary spasm.
Pharmacokinetics: Onset and Duration: Onset: Initial Response: Hypertension, oral: 24 to 96 hours.
Duration: Multiple Dose: Hypertension, oral: 24 to 48 hours.
Drug Concentration Levels: Time to Peak Concentration: Oral, immediate release: 6 to 9 hours.
Mean peak serum levels are linear and age-independent.
Steady-state serum levels have been observed after 7 to 8 days of chronic administration.
Absorption: Bioavailability: 64% to 90%, not affected by food.
Distribution: Amlodipine has high tissue affinity with large volume of distribution (V_d), V_d: 21 L/kg.
Protein binding is 93% to 98%.
Metabolism: Extensively metabolized to inactive metabolites in the liver (>90%).
Excretion: Renal: 60% as metabolites, 5 to 10% unchanged.
Feces, 20% to 25%.
Elimination Half Life: About 30 to 50 hours.
Impaired hepatic function: 56 hours.