HYPERTENSION DRUG LINKED TO CANCER IN ELDERLY.

Byline: Lawrence K. Altman The New York Times

Use of calcium channel blockers, one of the most widely prescribed classes of medications for high blood pressure and other ailments, has been tentatively linked to higher rates of cancer among older people in a federally financed study.

The risk of developing cancer was 72 percent higher among those who used the short-acting forms of calcium channel blockers in the study by a team led by Dr. Marco Pahor of the University of Tennessee in Memphis.

Pahor's report, made public Thursday, is to be published in Saturday's issue of The Lancet, an international journal published in London.

The percentage increase is equivalent to eight excess new cancers in each 100 people taking the drugs for five years, and 16 excess cancers over 10 years, Pahor said in an interview.

Pahor's team cautioned that its study did not establish cause and effect, but only a suggestive association. Nor, they said, did the study provide enough evidence to recommend that people should stop using calcium channel blockers, or calcium antagonists as they are also known.

Instead, the findings should be used to generate new studies to determine the degree of risk among the millions of people who take all forms of calcium channel blockers such as nifedipine, verapamil and diltiazem, Pahor's team said.

The drugs, some in both short- and long-acting forms, are marketed under a variety of brand names by several manufacturers.

Calcium channel blockers are the most widely prescribed class of drugs for high blood pressure. The Food and Drug Administration has also approved such drugs for treating a variety of ailments affecting the heart and the esophagus.

The study adds cancer to a list of possible dangers that scientists have linked to calcium channel blockers in recent months, including an increased risk of heart attacks and gastrointestinal bleeding. The studies generally have targeted the short-acting form of calcium channel blockers that are taken several times a day, not the newer forms that are taken once daily.

The studies have generated one of the sharpest medical controversies in recent years as cardiologists, epidemiologists, health officials and drug companies argue over the validity and interpretation of the findings. In an editorial, The Lancet criticized editors of other journals who have called for a moratorium on the subject, saying they had tarnished their journals' scholarly reputations.

Because of the intensity of debate and its importance to patients and doctors, a team from the Chaim Sheba Medical Center Heart Institute in Tel-Hashomer, Israel, led by Dr. Shimon Braun, took the unusual step of issuing a news release to coincide with the Lancet report about its own study, as yet unpublished and unreported.

Braun's study showed no increased risk of deaths from cancer among those taking calcium channel blockers.

Braun said his team is scheduled to report at a European meeting of cardiologists in Birmingham, England, next week. Bayer, the maker of one calcium channel blocker, helped write and distribute the news release about his findings.

Braun said a report of the findings was submitted a week ago to Circulation, a medical journal published by the American Heart Association in Dallas.

The Israeli and U.S. studies differed in the age and type of individuals studied. The Israeli study involved more than 11,500 patients with coronary artery disease ranging from 45 to 74 years of age. The U.S. study involved more than 5,000 residents 71 and over in East Boston, Mass., and two counties in Iowa who participated in a broad survey paid for by the National Institute of Aging.

Neither study is of a type designed to prove a cause-and-effect relationship between a hazard and a drug. Calcium channel drugs have been marketed in this country for many years, but critics say the current controversy over their safety reflects the fact that they were not subjected to the scientifically rigorous types of studies known as randomized controlled trials.