Study Links Use of Blood Pressure Drugs, Cancer Risk

Older people taking calcium channel blockers, a widely used class of drug for high blood pressure, got cancer at about twice the rate of people taking a different kind, a preliminary study reported.

But two makers of calcium channel blockers disputed the findings, and federal officials and researchers warned patients not to stop taking the drugs without consulting their doctors.

The study looked at diltiazem, nifedipine and verapamil. It included mainly older forms of the calcium channel blockers, and researchers said it is not clear whether the findings apply to patients taking the newer, one-dose-a-day versions now most widely used.

Dr. Richard Havlik of the National Institute on Aging said the study results suggest that the increase in cancer risk associated with the drugs would result in about two extra cancer cases a year per 100 people.

The study appears in the July issue of the American Journal of Hypertension. It was done by researchers at Catholic University in Rome and at the American aging institute.

The results were criticized by a spokesman for Pfizer Inc., which sells nifedipine as Procardia and the one-a-day Procardia XL.

In addition, Dr. Tim Shannon, director of medical research at Bayer Corp., which makes the nifedipine drugs Adalat and Adalat CC, also said that nifedipine is safe and that the new results are inconsistent with 20 years of worldwide experience and numerous clinical studies.

Researchers studied 750 people, age 71 or older, who were being treated for high blood pressure.