Viagra reduces heart attack risk

Scientists have discovered that Viagra, Pfizer's treatment for erectile dysfunction, could also be used to reduce stress that can lead to heart attacks.

In a placebo-controlled study at the Johns Hopkins University's Department of Medicine in Baltimore, scientists found that Viagra dampened the effect of artificially-induced stress to the heart, according to Dr. David Kass, the John Hopkins cardiology professor who directed the study.

"At the same time that [Pfizer] is enhancing erectile dysfunction, it's also blunting the stress that would be imposed by the act of sex," said Kass.

Participants in the study were injected with dobutamine, a drug that sped the heart rate "like stepping on the accelerator pedal," said Kass. Participants who took Viagra experienced less of an effect from the dobutamine, which was used to simulate physical or emotional stress.

Viagra, a blockbuster drug that totaled $1.7 billion in 2004 sales, works by increasing the flow of blood in the body, helping men with circulatory problems achieve erection, reports CNN.

Earlier research by Kass's team found that Viagra blocked the short-term effects of hormonal stress in the hearts of mice. They also found that, in mice, Viagra prevented and reversed the long-term cardiac effects of chronic high blood pressure.

In addition, Kass' group found that, in mice, Viagra reversed the negative effects on heart muscle weakened by heart failure and enlargement, a condition called hypertrophy.

In the current study, 35 healthy men and women with no signs of heart disease received two separate injections of dobutamine over three hours. Dobutamine increases heart rate and pumping strength. Between injections, the patients were given Viagra or a placebo. Then they all were given a second dobutamine injection.

After the first injection of dobutamine, the force of heart contraction increased 150 percent in all the patients. However, in the group treated with Viagra, the increased heartbeat was slowed by 50 percent.

"Viagra puts a brake on the effect of dobutamine," Kass said. "It reduces the stimulation of the heart so that the contraction of the heart was less strong."

Kass noted that his group is starting a clinical trial to see if Viagra can be effective in patients with heart failure. "If you gave a drug like Viagra not just acutely, but chronically, you might be able to improve heart function and reduce the chronic stress response in patients with hypertrophy," he said, informs Forbes.

P.T.