CHICAGO -- A study that had patients bicycling on their backs to simulate the rigors of sex suggests that many men with heart disease can safely take Viagra.
Fears about the effects of the impotence drug on heart patients have been stirred by reports of more than 100 heart attacks and deaths among users.
The latest study bolsters previous research showing that Viagra is unlikely to cause problems in heart patients who do not have severe disease and are not taking nitrate drugs.
Unlike some of the previous studies, the current research was not funded by Viagra's manufacturer. It was conducted through grants from the Mayo Foundation and the American Heart Association.
In 1999, the American Heart Association and American College of Cardiology said Viagra should not be used by the estimated 5.5 million U.S. heart patients taking nitrates for angina, or chest pain, because of the risk of a dangerous drop in blood pressure. The organizations also recommended caution in prescribing Viagra for patients whose heart disease includes ischemia, or insufficient oxygen to the heart.
The study had 105 men age 66 on average perform the exercise test twice, at least a day apart: once after taking Viagra and again after taking a dummy pill.
Most men developed ischemia during both tests, but Viagra did not increase the risk of ischemia, it did not worsen it and the condition was not severe or harmful, said Dr. Patricia Pellikka, a Mayo Clinic cardiologist.
No adverse effect
Viagra "had no adverse effect on symptoms or how long the men were able to exercise," she said.
The results appear in today's Journal of the American Medical Association.
The participants had diagnosed or suspected heart disease. Those on long-acting nitrates stopped taking them at least three days before the study. None of men had had significant rhythm disturbances, congestive heart failure or a heart attack within a month of the study.
The study is the first to examine Viagra's effects on the heart by using an exercise stress test that includes echocardiography, an ultrasound technique that shows images of the heart and its valves in action, Pellikka said. Having men cycle on their backs allowed for better imaging, she said.
Men bicycled for an average of 7.4 minutes, peddling against progressively increasing resistance.
"This study will go a long way toward making patients and physicians more comfortable with using" Viagra, Pellikka said.
Still, the researchers said heart patients who want to take Viagra should see their doctors and perhaps undergo a similar exercise test.