Viagra Helps Men With Heart Failure

The popular medication may even make patients more likely to take their heart failure drugs, says author Edimar Alcides Bocchi, M.D., associate professor and chief of the heart failure clinics at the Sao Paulo University Medical School in Brazil.

"Heart failure patients may become noncompliant with their congestive heart failure (CHF) treatment if they feel it causes or aggravates their ED," Bocchi says. "However, our study suggests that treating the ED may make patients more motivated to take their medicines."

Sildenafil caused no harmful effects and improved exercise performance during treadmill exercise tests in 23 men with CHF (average age 50) and a history of ED, says Bocchi.

Sildenafil blocks the activity of the enzyme phosphodiesterase type 5 (PDE5), which is active in multiple tissues and cells. The effects of PDE5 inhibition include increased production of nitric oxide, which is associated with improved function of the heart and blood vessels.

The cardiovascular effects of sildenafil have created some concern that the drug might be harmful in men with CHF. But there's not enough data on the safety or potential harm of sildenafil in CHF patients.

Most of the men had moderate or severe heart failure, and each had been referred for treatment of ED. On separate days, the men underwent two exercise treadmill tests, which consisted of a six-minute walk and a maximal exercise test. About an hour before the first test, the men received either 50 milligrams of sildenafil or a placebo. On the second day, the men received the opposite treatment (sildenafil or placebo) before exercise.

Those treated with sildenafil had significantly lower blood pressure and heart rate and improvement in measures of oxygen consumption and carbon dioxide production compared with those on placebo. Total exercise time also increased significantly. A separate evaluation showed that treatment with sildenafil was associated with higher scores on a questionnaire related to erectile function.

"Frequently, CHF patients, and especially their wives, are afraid their spouses will have heart failure symptoms or even death during sexual activity," says Bocchi. "Our study shows that the benefits may outweigh harmful side effects of treatment with sildenafil. The successful treatment of ED in CHF could not only improve sexual relationships but overall quality and success of CHF treatment."

Co-authors are Guilherme Guimarães, Ph.D.; Amilcar Mocelin, M.D.; Fernando Bacal, M.D.; Giovanni Bellotti, M.D.; and José Franchini Ramires, M.D.