Nifedipine
Nifedipine (Procardia)
Nifedipine
(nye- FED-ih-peen)
Pregnancy Category: C Adalat Adalat CC Adalat P.A. 10 and 20 Adalat XL Apo-Nifed Apo-Nifed PA Gen-Nifedipine Novo-Nifedin Nu-Nifed Procardia Procardia XL Taro-Nifedipine (Rx)

Classification: Calcium channel blocking agent (antianginal, antihypertensive)

See Also: See also Calcium Channel Blocking Agents .

Action/Kinetics: Variable effects on AV node effective and functional refractory periods. CO is moderately increased while peripheral vascular resistance is significantly decreased. Onset: 20 min. Peak plasma levels: 30 min (up to 4 hr for extended-release). t 1/2: 2-5 hr. Therapeutic serum levels: 0.025-0.1 mcg/mL. Duration: 4-8 hr (12 hr for extended-release). Low-fat meals may slow the rate but not the extent of absorption. Metabolized in the liver to inactive metabolites.

Uses: Vasospastic (Prinzmetal's or variant) angina. Chronic stable angina without vasospasm, including angina due to increased effort (especially in clients who cannot take beta blockers or nitrates or who remain symptomatic following clinical doses of these drugs). Essential hypertension (sustained-release only). Investigational: PO, sublingually, or chewed in hypertensive emergencies. Also prophylaxis of migraine headaches, primary pulmonary hypertension, severe pregnancy-associated hypertension, esophageal diseases, Raynaud's phenomenon, CHF, asthma, premature labor, biliary and renal colic, and cardiomyopathy. To prevent strokes and to decrease the risk of CHF in geriatric hypertensives.

Contraindications: Hypersensitivity. Lactation.

Special Concerns: Use with caution in impaired hepatic or renal function and in elderly clients. Initial increase in frequency, duration, or severity of angina (may also be seen in clients being withdrawn from beta blockers and who begin taking nifedipine).

Side Effects: CV: Peripheral and pulmonary edema, MI, hypotension, palpitations, syncope, CHF (especially if used with a beta blocker), decreased platelet aggregation, arrhythmias, tachycardia. Increased frequency, length, and duration of angina when beginning nifedipine therapy. GI: Nausea, diarrhea, constipation, flatulence, abdominal cramps, dysgeusia, vomiting, dry mouth, eructation, gastroesophageal reflux, melena. CNS: Dizziness, lightheadedness, giddiness, nervousness, sleep disturbances, headache, weakness, depression, migraine, psychoses, hallucinations, disturbances in equilibrium, somnolence, insomnia, abnormal dreams, malaise, anxiety. Dermatologic: Rash, dermatitis, urticaria, pruritus, photosensitivity, erythema multiforme, Stevens-Johnson syndrome. Respiratory: Dyspnea, cough, wheezing, SOB, respiratory infection, throat, nasal, or chest congestion. Musculoskeletal: Muscle cramps or inflammation, joint pain or stiffness, arthritis, ataxia, myoclonic dystonia, hypertonia, asthenia. Hematologic: Thrombocytopenia, leukopenia, purpura, anemia. Other: Fever, chills, sweating, blurred vision, sexual difficulties, flushing, transient blindness, hyperglycemia, hypokalemia, gingival hyperplasia, allergic hepatitis, hepatitis, tinnitus, gynecomastia, polyuria, nocturia, erythromelalgia, weight gain, epistaxis, facial and periorbital edema, hypoesthesia, gout, abnormal lacrimation, breast pain, dysuria, hematuria.

Laboratory Test Alterations: Alkaline phosphatase, CPK, LDH, AST, ALT. Positive Coombs' test.

Additional Drug Interactions: Anticoagulants, oral / Possibility of PT Cimetidine / Bioavailability of nifedipine Digoxin / Effect of digoxin by excretion by kidney Grapefruit juice / Nifedipine plasma levels R/T metabolism Magnesium sulfate / Neuromuscular blockade and hypotension Quinidine / Possible quinidine effect R/T plasma levels; risk of hypotension, bradycardia, AV block, pulmonary edema, and VT Ranitidine / Nifedipine bioavailability Theophylline / Possible effect of theophylline

How Supplied: Capsule: 10 mg, 20 mg; Tablet, Extended Release: 30 mg, 60 mg, 90 mg

Dosage
?Capsules
Individualized. Initial: 10 mg t.i.d. (range: 10-20 mg t.i.d.); maintenance: 10-30 mg t.i.d.-q.i.d. Clients with coronary artery spasm may respond better to 20-30 mg t.i.d.-q.i.d. Doses greater than 120 mg/day are rarely needed while doses greater than 180 mg/day are not recommended.
?Sustained-Release Tablets
Initial: 30 or 60 mg once daily for Procardia XL and 30 mg once daily for Adalat CC. Titrate over a 7- to 14-day period. Dosage can be increased as required and as tolerated, to a maximum of 120 mg/day for Procardia XL and 90 mg/day for Adalat CC.
Investigational, hypertensive emergencies.
10-20 mg given PO (capsule is punctured several times and then chewed).