Men who use erectile dysfunction drugs like Viagra and Cialis are more likely to have sexually transmitted diseases and doctors need to discuss the importance of safer sex practices, even with older patients, according to a new study.

That is the advice from researchers who contributed to a report in the latest issue of Annals of Internal Medicine which analysed insurance records of more than 1.4 million US men over 40. Anupam Jena of the Massachusetts General Hospital and his co-authors note that ED drugs have become popular since Viagra (sildenafil) was first introduced in 1998 and as early as 2002 it was estimated that up to 20% of US men over 40 had tried an ED drug.

In the study, the researchers collected data covering one year before and one year after the first prescription was filled. In both the year before and the year after, users had significantly higher rates of STDs than non-users and HIV/AIDS was the most frequently reported disease in both groups, followed by chlamydia. Since the prevalence of STDs did not markedly change after ED drug therapy began, the authors note that the difference between groups probably reflects higher-risk sexual practices among users of ED drugs.

The data gathered could not indicate whether ED drug use itself increased STD risk, but the authors are investigating that question in a further study. Dr Jena said that “anyone who does not practice safer sex, no matter their age, can contract an STD” and even though they are quite rare among older men –1 per 1,000 individuals – “we found that STD rates in men who used ED drugs were two to three times higher, both before and after they filled their first prescription”.
Previous studies have shown both that rates of STDs, including HIV/AIDS, are rising in older individuals as well as the general public and that people over 50 are much less likely than those in their 20s to use condoms during sex or be tested for HIV infection.