Name: Nifedipine (Procardia)
Class: Calcium-Entry Blocking Agent (Dihydropyridine)
Mechanism: Binds to L-type Ca2+ channels ® ¯ Ca2+ in arterial smooth muscle cells ® vasodilation ® ¯ TPR, coronary blood flow, ¯ cardiac afterload. Little/no effect on venous vessels. No direct effect on conduction or automaticity. Vasodilation ® reflex sympathetic response ® HR, contractility. Net = ¯ BP, HR, contractility, CO. May inhib. platelet aggreg.
Absorption: Oral ® nearly complete absorption. 1st pass Metabolism®¯ bioavail. IV.
Dist.: Significant protein binding.
Metabolism.: Hepatic. Inducible Metabolism. Inactive Metabolismolites.
Excretion, t½: 1.5-6 hr. Repeated oral dose ® t½ due to hepatic saturation. Longer t½ in elderly or pts w/hepatic cirrhosis or renal insuff.
Toxicity/S.E.s: Dizziness, hypotension, headache, flushing, peripheral edema, gingival hyperplasia. Aggravation of myocardial ischemia, angina. C/i w/CHF.
Utility: Rx angina (stable, variant, unstable), arrhythmias, hypertension. DOC for stable angina w/persistent HTN, sinus bradycardia, or AV node dysfxn. W/b-blocker & nitrate ® ¯ rest angina, ¯ risk of MI, ¯ risk of emergency revascularization.
Special Features: