LOS ANGELES, July 6 (Xinhua) -- Taking erectile dysfunction (ED) drugs such as Viagra may enhance the possibility of developing sexually transmitted diseases (STDs), a new study shows.
But it's the behavior that raises STDs rates, not the medication itself, according to the study jointly conducted by researchers at Massachusetts General Hospital and the University of Southern California.
The researchers examined health insurance claims records covering 1997 though 2006 from 44 large U.S. 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.
The findings showed that 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 fault lies not with the drugs but rather the high risk behaviors of the men who request them, the researchers noted.
The researchers said their study was 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.
The researchers urged doctors to counsel these patients about safe sex practices.
"Primary care doctors don't usually talk to older men about safe sexual practices, and that's partly because rates of STDs 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 STDs."
Jena speculated that HIV/AIDS was the most frequently reported STD 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 STD anonymously."
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 the study published in the July 6 issue of the Annals of Internal Medicine.