Pharmacologic Class: Calcium channel blocker. ACTIONS AND USESNifedipine is CCB generally prescribed for HTN and variant or vasospastic angina. It is occasionally used to treat Raynaud's phenomenon and hypertrophic cardiomyopathy. Nifedipine acts by selectively bloking calcium channels in myocardial and vascular smooth muscle, including those in the coronary arteries. This results in less oxygen utilization by the heart, an increase in cardiac output, and a fall in blood pressure. It is available as extended-release tablets (XL). ADMINISTRATION ALERTS Do not administer immediate-release formulations of nifedipine if an impending MI is suspected, or within 2 weeks following a confirmed MI. Administer nifedipine capsules or tablets whole . If capsules or extended-release tablets are chewed, divided, or crushed, the entire dose will be delivered at once. Pregnancy category C . PHARMACOKINETICS
Onset:10-30 min PO
Peak:30 min
Half-life:2-5 h
Duration:4-8 h(24 h extended release)
* ADVERSE EFFECTSAdverse effects of nifedipiine are generally minor and are related to vasodilation such as headache, dizziness, peripheral edema, and flushing. Immediate-acting forms of nifedipine can cause reflex tachycardia. To avoid rebound hypotension, the drug should be discontinued gradually. In rare cases, nifedipine may cause a paradoxical increase in anginal pain, possibly related to hypotension or heart failure.Contraindications: the only contraindication is prior hypersensitivity to nifedipine.INTERACTIONSDrug- Drug: when given concurrently, other antihypertensives have additive effects with nifedipine on blood pressure. Concurrent use of nifedipine with a beta blocker increases the risk of congestive heart failure. Nifedipine may increase serum levels of digoxin, leading to bradycardia and digoxin toxicity. Alcohol potentiates the vasodilating