A community-wide survey in San Francisco has found that gay men who recently used Viagra are more likely to be HIV-positive, have unprotected anal sex with partners of unknown HIV status, and use drugs. The study is published in the June 1st edition of the Journal of Acquired Immune Deficiency Syndromes.
Increased rates of unprotected anal sex, sexually transmitted infections, and HIV diagnoses were noted amongst gay men in San Francisco coincident to the marketing of Viagra (sildenafil) as a treatment for erectile dysfunction in the late 1990s, suggesting to some a connection between the medicine and unprotected sex. This appeared to be supported by a study which found that large numbers of gay men attending circuit parties had used Viagra, often in combination with recreational drugs and were four times more likely to have unprotected anal sex with a man of different or unknown HIV status. In addition a study involving gay men seeking treatment for sexually transmitted infections (STI), found that Viagra users had significantly more sexual partners and were more likely to have an STI. However, the link between Viagra use and riskier sexual practices is far from proven. A study in London found no link between Viagra use and unprotected sex but it did find a link with recreational drug use and Viagra.
Accordingly, in autumn 2001, investigators in San Francisco’s STOP AIDS! Project conducted a community-based study using a one page self-completed questionnaire enquiring into sexual risk taking, Viagra use and recreational drug use. A total of 837 gay men were recruited in gay neighbourhoods and at venues such as gay bars.
The average age of men participating in the study was 35, 67% were white and 66% had a college degree. The vast majority (76%) reported anal sex in the last six months, and 49% said they had always used a condom.
Viagra had been used by 32% of men at some time (CI: 29% - 36%), and 21% said they had used Viagra in the past six months. HIV-positive men were twice as likely to use Viagra, with 42% reporting recent use.
Recent Viagra use was significantly associated with increasing age (35 and older), being HIV-positive (44%), white ethnicity (26%), use of recreational drugs (24%) and unprotected anal sex with a partner of unknown or different HIV status (37%).
Amongst people with HIV, 11% reported using Viagra with HAART, although details on individual HAART regimens was not gathered.
Doctors were not the source of Viagra in the majority of cases, with 44% obtaining the medicine from friends, 6% from the internet and 4% from a street dealer. Doctors would therefore have been unable to offer advice to the majority of users about safe use of the drug, particularly dose reduction with protease inhibitors and NNRTIs and the avoidance of poppers.
”Recent Viagra use was nearly twice as common among men who reported unprotected anal sex with someone whose HIV status was unknown to them”, note the investigators.
Noting the association between Viagra use and the use of other recreational drugs, the investigators note that there is “the biological plausibility that Viagra can enable unsafe sex that otherwise may not have occurred. Situations where Viagra is combined with speed or other drugs present such a scenario.”
The investigators conclude “the strength and consistency of findings suggest that Viagra may be a new contributing factor to unsafe sex” and suggest that doctors prescribing Viagra should discuss with their patients potential drug interactions and HIV and STI transmission. Community based organisations should design such campaigns containing the same information for men who obtain Viagra from other sources.
HAART-treated patients are recommended to reduce the standard 50mg dose of Viagra by half and to take no more than 50mg in a 48 hour period. A 50% dose reduction is recommended for Cialis, another oral treatment for erectile dysfunction. Ritonavir can boost blood levels of both Viagra and Cialis upto sevenfold and these drugs should never be used by people taking ritonavir.
Both Viagra and Cialis can cause a dangerous drop in blood pressure if poppers are used with them.
Further information on this website
Viagra - overview
Sexual dysfunction - factsheet
Viagra use amongst gay men in London – implications for sexual risk taking - news story July 2001
HAART treated man dies after taking Viagra - news story June 1999
Chu PL et al. Viagra use in a community-recruited sample of men who have sex with men, San Francisco. JAIDS 33: 191 – 193, 2003.