July 1, 2003
Two previous studies in San Francisco have documented that Viagra use was associated with high-risk sexual behavior among men who have sex with men. They were limited, however, in generalizability due to their selected study populations: circuit party attendees and STD clinic attendees.
Researchers in the present study took the opportunity to survey a broader sample of MSM through the course of prevention outreach conducted by the STOP AIDS project. The purpose of this study was to gauge the magnitude of Viagra use among San Francisco MSM, its association with high-risk behavior, and its use in combination with other drugs.
Of the 837 men who completed the interview, the mean age was 35; 67 percent were white; 66 percent had a college degree. Seventy-six percent reported anal sex in the past six months; 49 percent reported always using condoms. Thirty-two percent had ever used Viagra; 21 percent had used Viagra in the past six months.
Recent Viagra use was significantly associated with increasing age, white race or "other" ethnicity, being HIV-positive, illicit drug use, and unprotected anal intercourse with a partner of unknown serostatus. In multivariate analysis, recent Viagra use was independently associated with having unprotected anal sex with a potentially serodiscordant partner, being HIV-positive, increasing age, illicit drug use, and white ethnicity. For the latter finding, Latino MSM were significantly less likely to have used Viagra in the past six months when using whites as the referent.
Thirty-six percent of all Viagra users combined it with other drugs, including speed (23 percent), ecstasy (18 percent), ketamine ("K" 11 percent), and gamma-hydroxybutyrate ("GHB" 8 percent). Eighteen percent combined Viagra with poppers -- a combination that can cause a fatal drop in blood pressure. Eleven percent of persons in treatment for HIV had combined Viagra with HAART. Ritonavir has been shown to increase the level of Viagra several-fold. Fifty-six percent of Viagra users obtained the drug from a source other than a physician. Forty-two percent of HIV-positive MSM reported Viagra use in the past six months. Recent Viagra use was nearly twice as common among men who reported unprotected anal sex with someone of unknown HIV serostatus.
"The strength and consistency of findings suggest that Viagra may be a new contributing factor for unsafe sex with the potential for increasing HIV transmission for some MSM," the researchers concluded. "Our study also points to prevention opportunities. Physicians prescribing Viagra are presented with an ideal moment to discuss not only potential drug interactions but sexual risk for HIV and STD with their patients. Community-based prevention providers are needed to develop campaigns and ensure that the same health education messages reach those who do not obtain Viagra from their physicians."