Active ingredient: Nifedipine - Brands, Medical Use, Clinical Data

Brands, Medical Use, Clinical Data

Drug Category

• Tocolytic Agents
• Vasodilator Agents
• Calcium Channel Blockers
• Dihydropyridines

Dosage Forms

• Capsule
• Tablet
• Tablet (extended-release)

Brands / Synonyms

Adalat; Adalat 10; Adalat 20; Adalat 5; Adalat CC; Adalat CR; Adalat Crono; Adalat Ft; Adalat Gits; Adalat Gits 30; Adalat LA; Adalat LP; Adalat Oros; Adalat PA; Adalat Retard; Adalate; Adapine; Adapress; Afeditab; Alat; Aldipin; Alfadal; Alonix; Alonix S; Alpha-Nifedipine Retard; Angipec; Anifed; Anpine; Apo-Nifed; Aprical; Bonacid; Calcibloc; Calcigard; Calcilat; Camont; Cardifen; Cardilat; Cardilate; Cardionorm; Chronadalate; Chronadalate Lp; Citilat; Coracten; Coral; Cordafen; Cordaflex; Cordalat; Cordicant; Cordilan; Cordipin; Corinfar; Corotrend; Corynphar; Depin; Dignokonstant; Dilafed; Dilcor; Dipinkor; Duranifin; Ecodipi; Ecodipin; Ecodipin E; Fedcor; Fedcor Retard; Fenamon; Fenamon Sr; Fenihidin; Fenihidine; Glopir; Hadipin; Hexadilat; Introcar; Kordafen; Macorel; Megalat; Myogard; N1fedilat; Nedipin; Nicardia; Nifangin; Nifar; Nifdemin; Nifebene; Nifecard; Nifecor; Nifedepat; Nifediac; Nifedicor; Nifedin; Nifedine; Nifedipine; Nifedipine Retard; Nifedipres; Nifedirex LP; Nifelan; Nifelat; Nifelat Q; Nifelate; Nifensar XL; Nificard; Nifidine; Nifipen; Niphedipine; Orix; Oxcord; Pidilat; Procardia; Procardia XL; Sepamit; Tibricol; Zenusin

Indications

For the management of vasospastic angina, chronic stable angina and hypertension.

Pharmacology

Nifedipine, the prototype of the dihydropyridine class of calcium-channel antagonists, is similar to other dihydropyridines including amlodipine, felodipine, isradipine, and nicardipine. Nifedipine is used to treat Prinzmetal's angina, hypertension, and other vascular disorders such as Raynaud's phenomenon. By blocking the calcium channels, Nifedipine inhibits the spasm of the coronary artery and dilates the systemic arteries, results in a increase of myocardial oxygen supply and a decrease in systemic blood pressure.

Mechanism of Action

Nifedipine inhibits the influx of extracellular calcium through myocardial and vascular membrane pores by physically plugging the channel. The decrease in intracellular calcium inhibits the contractile processes of smooth muscle cells, causing dilation of the coronary and systemic arteries, increased oxygen delivery to the myocardial tissue, decreased total peripheral resistance, decreased systemic blood pressure, and decreased afterload.

Absorption

Rapidly and fully absorbed following oral administration.

Toxicity

Symptoms of overdose include dizziness, drowsiness, nausea, severe drop in blood pressure, slurred speech, and weakness. LD₅₀=494 mg/kg (orally in mice); LD₅₀=1022 mg/kg (orally in rats)

Biotrnasformation / Drug Metabolism

Hepatic.

Contraindications

Known hypersensitivity reaction to nifedipine.

Drug Interactions

Beta-adrenergic Blocking Agents: Experience in over 1400 patients in a non-comparative clinical trial has shown that concomitant administration of nifedipine and beta-blocking agents is usually well tolerated, but there have been occasional literature reports suggesting that the combination may increase the likelihood of congestive heart failure, severe hypotension or exacerbation of angina.

Long Acting Nitrates: Nifedipine may be safely co-administered with nitrates, but there have been no controlled studies to evaluate the antianginal effectiveness of this combination.

Digitalis: Immediate Release Capsules: Since there have been isolated reports of patients with elevated digoxin levels, and there is a possible interaction between digoxin and nifedipine, it is recommended that digoxin levels be monitored when initiating, adjusting, and discontinuing nifedipine to avoid possible over- or under-digitalization. Extended Release Tablets: Administration of nifedipine with digoxin increased digoxin levels in 9 of 12 normal volunteers. The average increase was 45%. Another investigator found no increase in digoxin levels in 13 patients with coronary artery disease. In an uncontrolled study of over 200 patients with congestive heart failure during which digoxin blood levels were not measured, digitalis toxicity was not observed. Since there have been isolated reports of patients with elevated digoxin levels, it is recommended that digoxin levels be monitored when initiating, adjusting, and discontinuing nifedipine to avoid possible over- or under-digitalization.

Quinidine: Immediate Release Capsules: There have been rare reports of an interaction between quinidine and nifedipine (with a decreased plasma level of quinidine).

Coumarin Anticoagulants: There have been rare reports of increased prothrombin time in patients taking coumarin anticoagulants to whom nifedipine was administered. However, the relationship to nifedipine therapy is uncertain.

Cimetidine: A study in 6 healthy volunteers has shown a significant increase in peak nifedipine plasma levels (80%) and area-under-the-curve (74%) after a 1 week course of cimetidine at 1000 mg per day and nifedipine at 40 mg per day. Ranitidine produced smaller, non-significant increases. The effect may be mediated by the known inhibition of cimetidine on hepatic cytochrome P-450, the enzyme system probably responsible for the first-pass metabolism of nifedipine. If nifedipine therapy is initiated in a patient currently receiving cimetidine, cautious titration is advised.