San Francisco: Increased Risk of HIV and Sexually Transmitted Disease Transmission Among Gay or Bisexual Men Who Use Viagra
July 11, 2002
Sildenafil (Viagra) may be associated with unsafe drug use and sexual risk behavior. The potential role of Viagra in the resurgence of new STD and HIV transmission in San Francisco was investigated among men seeking public STD services in San Francisco from December 2000 to February 2001.Adapted from:
A one-page confidential survey on Viagra use and related risk behavior was distributed to a convenience sample of 844 male patients at clinic registration. The majority (57 percent; 480/844) of participants were heterosexual; however, 42 percent (352/844) were gay or bisexual. The median age was 32 years. Participants were more likely to be white (60 percent) than black (19 percent), Latino (12 percent) or other races (9 percent).
Overall, 17 percent of study participants reported using Viagra in the past year. Gay or bisexual men (31 percent; 108/352) were significantly more likely to use Viagra compared with heterosexual men (7 percent; 35/480). Further analysis focused on gay and bisexual men. Among those gay or bisexual men who used Viagra, over half received the drug from a friend (56 percent) rather than a health care provider (42 percent) or from other sources such as the Internet (2 percent). The use of Viagra in combination with illicit drugs such as ecstasy (43 percent), methamphetamines (28 percent), amyl nitrate (15 percent) and ketamine (8 percent) was common.
HIV-positive gay or bisexual men were slightly more likely to have used Viagra in the past year (39 percent; 26/67) compared with HIV-negative men (29 percent; 66/226). The prevalence of STD (gonorrhea, chlamydia or syphilis infection) at the survey visit was somewhat greater in Viagra users than non-users (32 percent vs. 23 percent). HIV-positive Viagra users had significantly higher proportions of current STD infection compared with HIV-positive non-users (50 percent vs. 26 percent).
Viagra users had a higher number of sex partners (anal and oral sex) in the past two months compared with non-users (mean 5.4 vs. 3.5). Among HIV-negative men who reported having anal sex partners in the past two months, a greater percentage of Viagra users reported recent unprotected serodiscordant anal sex (sex with a partner of opposite or unknown HIV serostatus) compared with non-users (30 percent vs. 15 percent). Gay or bisexual men who mixed Viagra with other drugs reported a greater number of sexual partners in the past two months than those who did not mix Viagra with other drugs (mean 5.5 vs. 2.8). HIV-negative Viagra mixers (n=31) were significantly more likely to report unprotected anal sex with a serodiscordant partner (44 percent vs. 16 percent) compared with HIV-negative men who used Viagra alone (n=35).
As a result of the cross-sectional nature of the study, direct causal inference about the risk of HIV/STD transmission secondary to Viagra use cannot be made. Using logistic regression, Viagra use was found to be independently associated with an increased number of partners and was also associated with having a prevalent STD after controlling for the number of partners. Whether these associations were found because Viagra enabled men to have more partners, increased the duration of sexual exposure to infected partners, or was a marker for higher risk sexual networks cannot be determined from the data. Researchers did not ascertain the direction of unprotected serodiscordant anal sex (i.e., insertive or receptive) to determine the risk of HIV transmission. Researchers said that considering the high-risk behaviors common in the study sample, study estimates are likely to be elevated compared with other gay or bisexual men.
The data highlight a significant relationship between Viagra use and sexual risk behaviors, drug use and new STD among a sample of gay or bisexual men in San Francisco. "It is incumbent on the manufacturer of Viagra and prevention health educators to inform gay or bisexual men of the risks of Viagra use taken outside of medical supervision, and to work with medical providers to ensure risk-reduction counseling along with the safe and proper use of this valuable drug," the authors concluded.
07.05.02; Vol. 16; No. 10: P. 1425-1428; Andrea A. Kim; Charlotte K. Kent; Jeffrey D. Klausner
This article was provided by CDC National Prevention Information Network. It is a part of the publication CDC HIV/Hepatitis/STD/TB Prevention News Update.