NIFEDIPINE TABLET 20MG

Indicatios:

Nifedipine tablets are indicated for the treatment of hypertension and the prophylaxis of chronic stable angina pectoris.

Dosage and administration：

Posology:

The recommended starting dose of Nifedipine is 10 mg every 12 hours swallowed with water with subsequent titration of the dosage according to response. Nifedipine permit titration of initial dosage, which may be adjusted upwards to 40 mg every 12 hours, to a maximum daily dose of 80 mg.

Method of administration

Oral use.

As a rule, tablets must be swallowed whole with a little liquid, either with or without food. Nifedipine tablets should not be taken with grapefruit juice.

The tablets should not be crushed, chewed, divided or dissolved.

Contraindications:

Nifedipine must not be administered to patients with known hypersensitivity to nifedipine or to other dihydropyridines because of the theoretical risk of cross-reactivity, or to any of the excipients.

Nifedipine must not be used in cardiogenic shock, clinically significant aortic stenosis, unstable angina, or during or within 4 weeks of a myocardial infarction.

Nifedipine should not be used for the treatment of acute attacks of angina.

The safety of Nifedipine in malignant hypertension has not been established.

Nifedipine should not be used for the secondary prevention of myocardial infarction.

Nifedipine should not be administered concomitantly with rifampicin since effective plasma levels of nifedipine may not be achieved owing to enzyme induction.

Precautions:

Nifedipine are not beta-blockers and therefore give no protection against the dangers of abrupt beta-blocker withdrawal; any such withdrawal should be a gradual reduction of the dose of beta-blocker preferably over 8 – 10 days.

Nifedipine may be used in combination with beta-blocking drugs and other antihypertensive agents but the possibility of an additive effect resulting in postural hypotension should be borne in mind. Nifedipine will not prevent possible rebound effects after cessation of other antihypertensive therapy.

Care must be exercised in patients with very low blood pressure (severe hypotension with systolic pressure less than 90 mmHg).

Nifedipine should not be used during pregnancy unless the clinical condition of the woman requires treatment with nifedipine. Nifedipine should be reserved for women with severe hypertension who are unresponsive to standard therapy.

Careful monitoring of blood pressure must be exercised when administering nifedipine with i.v. magnesium sulfate, owing to the possibility of an excessive fall in blood pressure, which could harm both mother and foetus. For further information regarding use in pregnancy.

Nifedipine are not recommended for use during breastfeeding because nifedipine has been reported to be excreted in human milk and the effects of nifedipine exposure to the infant are not known.

In patients with mild, moderate or severe impaired liver function, careful monitoring and a dose reduction may be necessary. The pharmacokinetics of nifedipine has not been investigated in patients with severe hepatic impairment . Therefore, nifedipine should be used with caution in patients with severe hepatic impairment.

Nifedipine should be used with caution in patients whose cardiac reserve is poor. Deterioration of heart failure has occasionally been observed with nifedipine.

The use of Nifedipine in diabetic patients may require adjustment of their control.

In dialysis patients with malignant hypertension and hypovolaemia, a marked decrease in blood pressure can occur.

Nifedipine is metabolised via the cytochrome P450 3A4 system. Drugs that are known to either inhibit or to induce this enzyme system may therefore alter the first pass or the clearance of nifedipine.

Drug-food interactions:

Grapefruit juice inhibits the cytochrome P450 3A4 system. Administration of nifedipine together with grapefruit juice thus results in elevated plasma concentrations and prolonged action of nifedipine due to a decreased first pass metabolism or reduced clearance. As a consequence, the blood pressure lowering effect of nifedipine may be increased. After regular intake of grapefruit juice, this effect may last for at least three days after the last ingestion of grapefruit juice. Ingestion of grapefruit/grapefruit juice is therefore to be avoided while taking nifedipine.

Storage:

Store at or below 25°C protected from light.