Middle-aged and older men who take erectile dysfunction drugs such as Viagra are more likely to have sexually transmitted diseases, a new study of more than 1.4 million men finds.
Researchers at Massachusetts General Hospital and the University of Southern California say the fault lies not with the drugs but rather the high risk behaviours of the men who request them. And doctors should counsel these patients about safe sex practices, they said.
Small studies of men who have sex with men have associated the use of ED drugs with higher risk behaviours and increased rates of STIs, but this report, published in the Annals of Internal Medicine, is said to be the first to examine the relationship between ED drugs and STD risk in a large, representative sample of privately insured older men.
The researchers had no way of knowing how many of the men were bisexual vs. homosexual.
"Primary care doctors don't usually talk to older men about safe sexual practices, and that's partly because rates of STIs are much lower in this group than in younger men, on the order of one per 1 000 individuals," said study author Dr Anupam B. Jena, an internal medicine resident at Massachusetts General.
"But what our findings suggest is that just by virtue of asking for an ED drug, these men are identifying themselves as being at two to three times higher risk of STIs."
Jena and his co-authors examined health insurance claims records covering 1997 though 2006 from 44 large US employers. The study group included about 34 000 male beneficiaries over 40 who used ED drugs, for whom the researchers collected data covering one year before and one year after the first prescription was filled, and nearly 1.37 million men over 40 who were non-users, for whom claims data was also collected.
Men who had been prescribed an ED drug were two to three times more likely than non-users to have sexually transmitted diseases, and this was true both in the year before and after the first prescription was filled.
The most frequently reported STD was HIV/Aids, followed by chlamydia. The data gathered could not indicate whether ED drug use itself increased STI risk, but Jena said he and his colleagues are investigating that question in a separate study.
Jena speculated that HIV/Aids was the most frequently reported STI because "the symptoms that are associated with a primary HIV infection are the kinds of things that make men more likely to show up to a doctor, rather than go to a free clinic where they know they can get tested for an STI anonymously."
Not just men with ED who use
Use of medication to treat ED has grown significantly since the introduction of sildenafil (Viagra) in 1998, and earlier research has found that men over 50 are much less likely than young men to use condoms, according to background information in the study.
"This study confirms what we've suspected for a while, which is that the men who are using these drugs aren't just those who have erectile dysfunction, but they're also men in high risk groups who take it to enhance sexual activity," said Dr. Peter Leone, a professor of medicine at the University of North Carolina and board chair of the National Coalition of STI Directors. "So it's not that the drug is leading to the behaviour. It's really the other way around."
The findings suggest a need for greater responsibility in prescribing ED medications, added Leone. "Doctors need to realise that unless these patients are always using condoms or are in mutually monogamous relationships, they need routine STI screening with repeated follow-ups." - (HealthDay News, July 2010)