Viagra helps men with heart disease live longer, study suggests
Taking Viagra may bring an unexpected benefit for men with heart disease.
The erectile dysfunction drug increases blood flow to the penis by blocking a specific enzyme.
The NHS stresses Viagra should not be taken by men who have recently had a heart attack or stroke, however, scientists from the Karolinska Institute in Sweden have previously revealed the drug may protect against cardiovascular conditions.
To learn more, the same team analysed men with stable coronary artery disease; generally defined as the narrowing of the arteries that supply the heart without causing any major symptoms. Over time, the condition can trigger heart attacks and strokes.
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More than 16,500 of the participants took Viagra or a drug of the same class, while just under 2,000 of the men were on the erectile dysfunction medication alprostadil; a cream, injection or pellet that dilates the blood vessels in the penis.
Results reveal the men on Viagra were more likely to be alive just under six years later.
Erectile dysfunction becomes more common with age, affecting 50% to 55% of men between 40 and 70 in the UK.
Impotence is associated with a higher risk of poor heart health and premature death among men with and without cardiovascular disease, the scientists wrote in the Journal of the American College of Cardiology.
Viagra is the brand name for the generic drug sildenafil, which can be prescribed or bought over-the-counter from pharmacies in the UK.
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When taken 30 to 60 minutes before sex, at least two-thirds of men have improved erections.
Sildenafil reduces blood pressure and is therefore sometimes prescribed for pulmonary hypertension; high blood pressure in the vessels that supply the lungs.
Viagra's blood pressure-lowering quality means it is not generally recommended for men with coronary artery disease. Dangerously low blood pressure can cause heart attacks and strokes.
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The Karolinska scientists analysed male coronary artery disease patients, some of whom were expected to have a heart attack in at least six months' time.
The remainder were due to have a balloon dilation – a procedure that opens up a narrowed artery; or coronary artery bypass surgery – when blood is redirected around a blocked artery in the heart.
"The risk of a new heart attack is greatest during the first six months, after which we consider the coronary artery disease to be stable," said lead author Professor Martin Holzmann.
The results reveal 14% of the men treated with Viagra or a fellow so-called PDE5 inhibitor died within the 5.8 year follow-up period, compared to just over a quarter (26%) in the alprostadil group.
Viagra was therefore associated with a 12% reduced risk of death.
Men on the drug were also less likely to endure a new heart attack or heart failure; when the organ is unable to pump blood around the body sufficiently.
Taking Viagra or similar was also linked to a lower need for balloon dilation or bypass surgery.
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The results were dose-dependent, with more frequent PDE5 inhibitor use linked to a lower risk.
"This suggests there's a causal relationship, but a registry study can't answer that question," said Professor Holzmann.
"It is possible those who received PDE5 inhibitors were healthier than those on alprostadil and therefore had a lower risk.
"To ascertain whether it is the drug that reduces the risk, we would need to randomly assign patients to two groups, one that takes PDE5 and one that doesn't.
"The results we have now give us very good reason to embark on such a study."
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