Nifedipine is indicated in the management of all types of essential and renal hypertension. It is also used in the treatment of hypertension during pregnancy and during coronary bypass surgery.

Nifedipine is used for the prophylaxis and treatment of unstable and variant angina, myocardial infarction, and silent myocardial ischemia. In addition, it is also indicated in Raynaud’s phenomenon and heart failure.

Nifedipine is a calcium channel blocker that inhibits the transmembrane influx of calcium ions into muscle cells. It has selective vasodilatory effects on arterial vessels. It dilates the main coronary and systemic arteries, leading to a fall in blood pressure. This triggers a sympathetic reflex response that may cause tachycardia and increased cardiac output. Pulmonary arterial pressure is also reduced. At higher doses, Nifedipine may exert direct negative inotropic effects on cardiac muscle, although arterial vasodilation occurs at lower doses.

Nifedipine 10 mg:

• Angina: Initially 10 mg 3 times daily with food increased to 20 mg 3 times daily if necessary, in elderly patients, initially 5 mg 3 times daily.
• Raynaud's Phenomenon: 10 mg 3 times daily; maximum 60 mg daily. In urgent cases, the tablet should be dissolved under the tongue like a sublingual tablet. The effect occurs within some minutes.

Nifedipine 20 mg: The starting dose for patients not previously prescribed Nifedipine products is one tablet once daily. The recommended dose in hypertension and angina prophylaxis is 20 mg twice daily during or after food. Dosage may be adjusted within the range 10 mg twice daily to 40 mg twice daily.

Patients with liver dysfunction should commence therapy with 10 mg twice daily with careful monitoring.

Patients with renal impairment do not require adjustment of dosage.

• ACE inhibitors: May enhance hypotensive effect.
• Anti-arrhythmics: Plasma concentration of quinidine may be reduced.
• Anti-bacterials: Rifampicin may increase the metabolism of Nifedipine.
• Anti-epileptics: Plasma concentration of phenytoin may increase.
• Antipsychotics: May enhance hypotensive effect.
• β-blockers: Occasionally severe hypotension and heart failure may occur.
• Cyclosporin: Plasma concentration of Nifedipine may increase.
• Muscle relaxants: Effect of neuromuscular blockers such as tubocurarine may be increased.
• Ulcer healing drugs: May increase the metabolism of Nifedipine.

Cardiogenic shock, advanced aortic stenosis, nursing mothers, gastrointestinal obstruction, inflammatory bowel disease, and hypotension.

Reported side effects include headache, flushing, lethargy, peripheral (gravitational) oedema, rash, nausea, increased frequency of urination, eye pain, gum hyperplasia, depression, tremor, photosensitivity, and rare cases of jaundice. These effects may disappear after discontinuation. In some angina patients, initiation of therapy may provoke ischaemic pain.

There are no adequate and well-controlled studies in pregnant women. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Tablets should be swallowed whole and should not be chewed or broken. It should be used cautiously in patients with poor cardiac reserve. If ischaemic pain occurs or worsens after starting therapy, treatment should be discontinued. Diabetic patients may require dose adjustment. Use with caution in renal disease as absorption may be altered.

Calcium-channel blockers

Protect from strong light and store in a cool place in the original pack.