NEW YORK (Reuters Health) - Although heart attacks and heart-related deaths have occurred in men taking the anti-impotence drug Viagra (sildenafil), results of a new study suggest that the drug is safe for men with heart disease who are not taking nitrate drugs.

Viagra should not be used by men taking nitroglycerin or other nitrate drugs, which are prescribed for heart disease-related chest pain. However, in a small study of men with severe heart disease who were not taking nitrates, a dose of Viagra did not cause any heart-related complications. The men did not have sex while on the drug but were given a medication that puts stress on the heart.

In the study, Dr. Howard C. Herrmann, of the University of Pennsylvania in Philadelphia, and colleagues measured the effects of Viagra on blood flow in 14 men with severe heart disease. In all of the men, at least one artery delivering blood to the heart was at least 70% blocked. Many of the men had heart attack risk factors, including diabetes, high blood pressure and smoking.

On most measures of blood pressure and blood flow, Viagra did not appear to have any significant effect, the researchers report. And none of the men in the study experienced any serious side effects, like low blood pressure or chest pain, that could be linked to Viagra. The researchers measured the heart and lung function of the subjects when they were lying down before and 45 minutes after taking a dose of Viagra.

``It's further evidence that Viagra is a safe drug'' for patients in general and heart patients specifically, Herrmann told Reuters Health in an interview. Patients and their physicians should be reassured by the news, he said.

The results of the study, which was funded by Viagra's manufacturer, New York-based Pfizer Inc., are published in the June 1st issue of The New England Journal of Medicine.

According to Herrmann, there are several possible explanations for the heart attacks and deaths that have occurred in men taking Viagra. Some of the men may have been taking drugs that contain nitrates, which can lead to a dangerous drop in blood pressure when used in combination with Viagra, he said.

Herrmann also noted that many men might not have been physically fit enough for sex. After taking Viagra, they were able to have an erection, but their sedentary bodies may not have been strong enough for the physical activity of sex, he said. The over-exertion, rather than the drug itself, may have led to the heart problems, according to Herrmann.

Finally, large numbers of men have both erectile dysfunction and heart disease, and it would be expected that some of them would have heart attacks, regardless of whether or not they used Viagra, Herrmann noted.

``In conclusion, this study demonstrates that oral sildenafil has no direct adverse cardiovascular effects in men with severe coronary artery disease,'' Herrmann and his colleagues write. They conclude that the drug is safe for men with heart disease, provided that their condition is stable and that they are not taking medications containing nitrates.

The American College of Cardiology and the American Heart Association recommend that patients with stable coronary disease who are not taking nitrates should consult their physician about the risks and benefits of taking Viagra. Those taking a combination of blood pressure-lowering drugs may be at increased risk for drug interactions, they note.

Measuring heart function during an exercise stress test can help determine if a patient may experience heart problems during sex, according to the statement.

``We wish to stress that the physical and emotional stresses of sexual intercourse can be excessive in some people, particularly those who have not performed this activity in some time and who are not in good condition,'' they write. This alone may cause chest pain or trigger a heart attack in some people, according to the AHA and ACC. ``Such patients should be advised to use common sense and to moderate their physical exertion and their emotional expectations as they begin their experience with taking Viagra,'' they add.

SOURCE: The New England Journal of Medicine 2000;342:1622-1626.

(From Yahoo)