COPYRIGHT 1998 Charles W Henderson

Warnings about the possible health risks of Viagra have been added to the drug's label after 69 men were reported to have died after taking it, the U.S. Food and Drug Administration (FDA) said.

While stressing that it still believes Viagra is safe, the FDA said the warnings make clear that patients who have a history of heart attack, severely low blood pressure, or other kinds of heart disease, should be examined carefully before being prescribed the drug.

The FDA said Viagra's maker Pfizer was changing the label to take account of reports of deaths and severe side effects in some of the millions of men who have taken the blockbuster impotence drug since it went on the market in April 1998.

"The revised labeling addresses post-marketing reports of heart attacks, sudden cardiac deaths, and hypertension," the FDA said in a statement. It also noted that patients who have heart disease are at risk from sexual activity anyway and have to be especially careful if they use Viagra.

It also warns of the risk of priapism - a prolonged and painful erection. "This is a serious condition that requires immediate medical attention. The labeling advises patients to seek prompt medical attention if their erection lasts longer than four hours."

The FDA noted that many men were left out of the original safety trials for Viagra, including men who had suffered heart attacks, stroke, or dangerous arrhythmia within six months; men with dangerously high or low blood pressure; men with heart failure or unstable angina (chest pains); or retinitis pigmentosa, an eye disorder.

"The new labeling notes that if Viagra is prescribed for these patients, it should be done with caution," it said.

Pfizer already warns that people taking nitrate-based drugs for their heart disease must not use Viagra, as the drug interaction can kill them.

"Revised in consultation with FDA, the new labeling is intended to help make sure that consumers and doctors are fully informed about the benefits and risks of using Viagra, know that consideration must be given to the cardiovascular status of patients prior to prescribing Viagra, and know how to safely use the drug," the FDA said.

The FDA said it was not unduly worried about the reports that have flooded in about Viagra. "Reports involving Viagra constitute only a small fraction of the more than 6 million prescriptions written for this drug. FDA continues to believe Viagra is safe and effective if used according to the updated labeling," it said.

In August 1998, the FDA said it was studying reports that at least 69 people had died while taking Viagra, known generically as sildenafil. The drug is only approved for prescription to men, but some doctors say they are also giving it to women. It works by increasing blood flow to the sexual organs.