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Viagra and Cialis for heart failure?

Erectile dysfunction drugs may do what no others have done.

Sildenafil (Viagra) treats erectile dysfunction (ED) by blocking (or inhibiting) an enzyme called PDE5. This relaxes arteries that send blood to the penis, causing it to enlarge. Viagra and similar ED drugs also relax the arteries of the heart. Now there is evidence that PDE5 inhibition may be an effective treatment for heart failure (HF). Harvard researchers have shown that Viagra can improve exercise capacity in people with this chronic disease. In May, the researchers received a $26.3 million grant from the National Institutes of Health to study whether the PDE5 inhibitor Cialis can extend length of life in people with heart failure and reduce heart failure-related hospitalizations.

As medical director of the Heart Failure and Cardiac Transplant Program at Harvard-affiliated Massachusetts General Hospital, Dr. Marc Semigran is always on the lookout for better treatments for HF. When Viagra came on the market in 1997, he immediately saw its potential to lower lung pressures in pulmonary hypertension, a condition affecting about three-fourths of people with left-sided HF.

“Increased pressures cause the right ventricle to malfunction and, I believe, contribute to decreased exercise capacity, increased fatigue, and breathlessness,” says Dr. Semigran. Clinical trials quickly proved that Viagra could improve these parameters by 20%.

A potential lifesaver

Today, Dr. Semigran’s target is heart failure itself. The condition causes episodes of severe fluid retention that contribute to the progression of HF and often require in-hospital treatment—a source of frustration for patients. Animal studies performed at Johns Hopkins University suggest that Viagra may quickly reverse the damage to heart muscle these epidsodes cause.

Dr. Semigran will use the NIH grant to coordinate a clinical trial in humans evaluating the effects of a PDE5 inhibition on length of life and hospitalizations. The trial will enroll 2,100 people with pulmonary hypertension and left-sided HF at 100 sites in the U.S. and Canada.

“We all think this is an exciting new potential therapy for HF. We already know these medications are safe and well tolerated, because billions of people take them. We are fairly convinced they improve exercise capacity, but we want to know whether they also improve survival,” says Dr. Semigran.

The answer will be available in about five years.

Posted by: Dr.Health

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