Nifedipine Pharmacology

Nifedipine is a dihydropyridine calcium channel blocker that selectively inhibits L-type calcium channels in vascular smooth muscle, leading to vasodilation and reduced peripheral vascular resistance. The extended-release formulation of nifedipine provides more stable plasma concentrations and is preferred for chronic management of hypertension and angina. Common adverse effects include headache, flushing, peripheral edema, and dizziness, all related to its vasodilatory action. Nifedipine undergoes extensive first-pass metabolism in the liver, primarily via CYP3A4 enzymes, which significantly influences its bioavailability and potential drug interactions. CYP3A4 inhibitors (e.g., ketoconazole, erythromycin, grapefruit juice) can increase plasma levels of nifedipine, raising the risk of hypotension and adverse effects.