FDA Panel Verdict On Calcium Blockers

The labelling for immediate-release nifedipine products made by Bayer (Adalat), Pfizer (Procardia) and numerous generic companies should be altered to reflect an increased risk of myocardial infarction when given off-label to hypertensives. However, the products are safe to use for their approved indications of vasospastic angina and chronic stable angina.

This was the key recommendation made by the US Food and Drug Administration's Cardiovascular & Renal Drugs Advisory Committee at its meeting on January 24 to discuss the ongoing calcium channel blocker (CCB) dispute, which surfaced last year with the publication of three studies which suggested that use of some of these agents for hypertension may increase the risk of myocardial infarction (Marketletters passim).

The labelling changes for immediate-release nifedipine, which will probably appear as some form of boldface warning in the indications section, will caution against the use of the drug in hypertension, hypertensive crisis, acute MI and some forms of unstable angina. No such changes were recommended for two other drugs under consideration, immediate-release verapamil (Searle's Calan/Knoll's Isoptin) and diltiazem (Hoechst Marion Roussel's Cardizem). Of all these products, only verapamil is indicated for hypertension.