Make recreational use of Viagra illegal say US investigators

Recreational use of erectile dysfunction drugs is associated with an increased risk of unprotected sex, and an increased risk of sexually transmitted infections, including HIV, according to an article published in the May 26^th edition of the American Journal of Medicine. The investigators recommend that product labeling for erectile dysfunction medication should be altered to warn users of “an increased risk of sexually transmitted infections, including HIV.” In addition, they recommend that consideration should be given to making recreational use (and dealing) of erectile dysfunction illegal.

Sildenafil (Viagra), tadalafil (Cialis), and vardenafil (Levitra) are oral drugs licensed for the treatment of erectile dysfunction. Evidence emerged soon after the licensing of Viagra in 1999 that the drug was being used without prescription, and that its use was associated with sexual risk taking and an increased risk of sexually transmitted infections, including HIV.

US doctors undertook a review of published studies looking at the prevalence of the use of Viagra and its association with sexually transmitted infections, including HIV. Studies from 1999 onwards were reviewed and were identified using a PubMed search and by contacting investigators working in the field of HIV and sexual health.

A total of fourteen studies met the investigators’ search criteria and were analysed.

Prevalence of Viagra use

The 14 studies showed that use of Viagra varied by population, location and time. Prevalence of use ranged from 3% in a sample of UK men and women attending dance clubs in 1999 to 32% of gay men in San Francisco in 2000 – 01.

A total of eleven of the 14 studies were focused on Viagra use by gay men. The majority of these (seven) found that over 10% of gay men had used the drug and one study conducted in San Francisco found particularly high levels of use by HIV-positive gay men (42%).

Levels of Viagra by gay men and heterosexual men were compared in one study conducted in San Francisco. This found much higher usage of the drug by gay men (31%) than by straight men (7%).

Use of Viagra with other recreational drugs

Eleven studies looked at the use of Viagra with recreational drugs and all found that sildenafil was used alongside illicit substances. One study, involving men using a municipal sexual health clinic in San Francisco found that Viagra users were over three times more likely to have used methamphetamine in the previous four weeks.

Source of Viagra

The four studies that examined where users of Viagra obtained the drug from found that the majority of users obtained the drug without a prescription (57% to 83%).

Risky sexual behaviour

Eleven studies examined the behavioural outcomes of Viagra use and three studies looked at biological outcomes (sexually transmitted infections).

Amongst gay men, the studies indicated increased odds of unprotected anal sex with a partner of unknown or different HIV status ranging (mean risk ratio 3.9).

Studies in San Francisco also found that gay men who used Viagra had more sexual partners compared to non-users of the medicine.

Three studies focused on Viagra use and sexually transmitted infections. At a sexual health clinic in San Francisco, sildenafil users were over twice as likely to be diagnosed with a bacterial sexually transmitted infection than non-users. In another study conducted at a San Francisco sexual health clinic, gay men who used Viagra and methamphetamine were six times more likely to diagnosed with early syphilis. Another study in San Francisco included a population of gay men attending for repeat HIV tests. Gay men using Viagra were over twice as likely to test HIV-positive than non-users.

“The reviewed studies establish a substantial level of sildenafil use among a variety of samples of men who have sex with men”, write the investigators. They note that Viagra was often obtained without prescription, combined with other recreational drugs, and was associated with risky sexual behaviour “including unprotected anal sex with a partner of unknown of serodiscordant HIV status.”

Studies indicated at as many as a third of gay men with a median age of 32 years were using Viagra. The investigators do not believe that erectile dysfunction could account for such a high level of use of the drug amongst such a young population. They note, however, that Viagra can improve sexual performance when taken with recreational drugs such as ecstasy and methamphetamine, illicit drugs that can induce erectile problems. They suggest “the mixing of methamphetamines and sildenafil…becomes particularly troublesome given the fact that the user is under the influence of these substances and may thus have impaired decision making capabilities with regard to sexual risk behaviour and the prevention of STDs, including HIV.” Increased prevalence of sexually transmitted infections amongst gay men in large US can be explained, in part at least, by use of erectile dysfunction drugs, suggest the investigators.

The investigators conclude by recommending that the product label of erectile dysfunction drugs “should be modified to warn users of an increased risk for STDs, including HIV infection.” Expressing concern about the widespread recreational use of these medicines they further recommend that “consideration should be given to scheduling this class of drug as a controlled substance.”

An accompanying editorial says that the investigators’ analysis “should raise considerable anxiety among physicians and patients” and notes a “worrisome” increased rate of risky sexual behaviour amongst gay men using erectile dysfunction drugs.

The author of the editorial states that his “public health” anxieties were further raised by the “New York resistance case” involving a gay man who appeared to have been infected with a resistant and virulent strain of HIV. The author notes the patient used methamphetamine and sildenafil and writes “the question that immediately leaped to my mind was: what effect did the combined abuse of these drugs have on the patient? Could this have resulted in the development of the highly virulent HIV mutant? Does this combination drug abuse increase the likelihood of STD transmission and a propensity to unsafe sex?”