ORLANDO, Florida -- Despite concerns that the impotence drug Viagra could lead to heart attacks, several new studies show the drug doesn't hurt the heart -- in fact, it might help.
In one study of 5,600 men in England, those who took Viagra were no more likely to have a heart attack than those who didn't.
"Our analysis showed no evidence for an increased risk of [heart attack or ischemic heart disease]" the authors wrote. "The rates observed were similar to those for the general population of men in the [United Kingdom]."
The research was done at the Drug Safety Research Unit, a private group in Southampton, England. The study was done at the request of the European Medicine Evaluation Agency, a regulatory agency of the European Union, and paid for by Pfizer, Inc., the company that makes Viagra, according to Dr. Saad Shakir, the lead author of the study. He added that Pfizer had no control over the study. The report was released at a meeting of the American College of Cardiology.
After Viagra went on the market in 1998, reports came in to the U.S. Food and Drug Administration of men taking Viagra, having sex, and then having heart attacks. At the time, cardiologists theorized that the men were having heart attacks because they weren't physically fit to have sex, but said more studies needed to be done.
The study in England, along with others like it, show that "sildenafil [Viagra] can be used safely in most patients with cardiovascular disease," according to Dr. Adolph Hutter, a cardiologist at Massachusetts General Hospital and professor of medicine at Harvard Medical School.
Hutter was co-chairman of a 1998 joint task force of the American College of Cardiology and the American Heart Association that set guidelines for doctors who prescribed Viagra to men with heart disease.
Even though Viagra appears to be safe for men with heart disease, Hutter still urged caution, especially since some men who take Viagra have not had sex in many years.
"Take it easy, don't try to prove anything as you resume having sex again," he said. "There's sex that's physical and there's sex that's relaxed. Relaxed sex is the way to go."
He added that the choice of partner makes a difference. "There might be more nervous tension and anxiety if it's not your spouse." he said.
Another study being presented at this week's meeting suggested that men who take Viagra might be able to exercise longer. In the study at the Heart Institute of Sao Paulo, 18 men were able to exercise for 14 minutes after taking Viagra, and for 12 minutes when on a placebo.
"It's not a big difference, but it is statistically significant," Hutter said.
A third study might explain why the men could exercise more. The study on 27 patients suggests that Viagra decreases arterial stiffness, which some theorize could lead to an increased ability to exercise.
The joint guidelines from the AHA and the ACC emphasized that there is one group of men who should absolutely not take Viagra: those who take drugs that contain nitrates in any form. The combination of nitrates and Viagra could send blood pressure down to dangerously low levels.
Hutter suggested that men with low blood pressure test out Viagra without having sex first.
"Start out with a modest dose, such as 50 milligrams, then check your blood pressure 40 minutes after the dose to make sure your blood pressure hasn't dropped," he said. "And if you want to take 100 milligrams, try the test again with 100 milligrams."
