Viagra use among gay men in London-implications for sexual risk taking

Researchers from the Royal Free Medical School in London have released data from a study of Viagra use among gay and bisexual men attending one of five gyms in central London.

The study, carrried out between March and April 1999 (relatively soon after the licensing of the drug in the UK), analysed data from 677 HIV-positive and HIV–negative men.

In total, 15% of the study population (n=100) had used Viagra. HIV-positive men were significantly more likely than HIV-negative and untested men ever to have taken Viagra; (27%, 14% and 7% respectively).

A startling 83% of the men who had taken Viagra had used it recreationally, without prescription. The remaining 17% (less than one in five) had been prescribed Viagra.

Researchers found no difference in the ratio of prescription to recreational use when they analysed by HIV status.

82% of the men had taken Viagra more than once and 63% had combined it with other recreational drugs.

More than half (59%) of the HIV-positive men who had taken Viagra were also taking HAART. Potentially fatal interactions between protease inhibitors and Viagra have been widely reported in the positive press, but the researchers underlined the need to ensure HIV-positive men and their clinicians are aware of this.

Sexual risk behaviour

HIV-positive and negative men who had ever taken Viagra were more likely to report unprotected anal intercourse (UAI) with a serodiscordant partner. HIV-negative men who had ever used Viagra were more likely to report UAI with a partner whose status they did not know.

Reports of UAI with serodiscordant partners among HIV-negative men who had used Viagra in the previous three months were higher than those reported by HIV-negative men who had never used the drug (8% v 1.4 %). No such correlation was found for HIV-positive men.

.Whilst previous Viagra use was associated with high risk sexual behaviour among both HIV-positive and HIV-negative gay men, the researchers concluded that these men may have added Viagra to their risk-taking repertoire rather than Viagra being the cause of an increase in risk behaviour.

HIV-negative men were more likely to report serodiscordant UAI in the previous three months, while actually taking the drug, than those who had never taken it (8.0% v 1.4%). Rates of UAI with serodiscordant partners among HIV-positive men while taking Viagra were barely different to rates seen among HIV-positive men who had never taken it (4.0% v 3.8%).

The rise in unprotected sexual activity among HIV-negative men with partners of a different HIV status places them at increased risk of exposure to HIV. The auhtors emphasise that HIV-positive men using Viagra recreationally must be reminded of the potential interactions with protease inhibitors.