ORLANDO, Mar 20 (Reuters Health) - Although Viagra is dangerous when taken in combination with certain heart medications, new study findings suggest that the impotence drug may actually have some beneficial effects on some men with congestive heart failure.
The drug, sildenafil, appears to improve exercise tolerance in men with congestive heart failure, a chronic condition in which the heart is enlarged and pumps inefficiently, causing patients to feel fatigue, breathlessness and end up with fluid accumulation in the limbs and lungs. The findings were presented on Monday at the American College of Cardiology meeting here.
"I don't think anyone would say sildenafil is protective," cautioned Adolph Hutter of Massachusetts General Hospital in Boston. The study authors note that use of Viagra by patients with congestive heart failure is "potentially hazardous."
Hutter explained, however, that some studies suggest that the drug may increase the amount of blood and oxygen delivered to the heart muscle.
In the new study, Edimar Bocchi of the Heart Institute of Sao Paulo University Medical School in Brazil, and colleagues looked at 23 men with congestive heart failure and erectile dysfunction of more than 6 months duration. The study participants were asked to perform a 6-minute walk test--roughly the equivalent amount of exertion required during sexual intercourse, Hutter noted. They also performed an exercise test on a treadmill. The researchers repeated the tests 60 minutes and 90 minutes after the men took a standard dose of Viagra.
Bocchi told meeting attendees that Viagra improved exercise tolerance by about 5 minutes and did not affect heart rate or systolic blood pressure during exercise. Hutter and Bocchi said that understanding how Viagra works may lead to the development of drugs that are heart protective.
And Hutter stressed that the only "absolute contraindication" to the use of Viagra is the use of nitrates 24 hours before and after taking Viagra. Nitrates, which include drugs such as nitroglycerin, help heart patients by dilating the arteries and causing blood pressure to fall. However, when nitrates are taken with Viagra, the combination can be deadly.
The researchers also pointed out that many patients with severe heart failure may also have low blood pressure, and such patients should not take Viagra.
"Most men with cardiovascular disease can safely take sildenafil," Hutter said. The exception is men with "borderline low blood pressure," he added. He defined that as a systolic pressure (the first number in a blood pressure reading) of 110 mm Hg or less.
Men with heart problems and erectile dysfunction should consult their doctor to find out if Viagra is safe in their situation. |
关闭窗口