A daily dose of the antibiotic doxycycline may be effective as pre-exposure prophylaxis (PrEP) against gonorrhea, chlamydia and syphilis, aidsmap reports. Publishing their findings in Sexually Transmitted Diseases, researchers conducted a pilot study of 30 HIV-positive gay men and transgender women who had contracted syphilis at least twice since being diagnosed with HIV. They were randomized either to take 100 milligrams of doxycycline each day for 36 weeks or to receive financial incentives for remaining free of sexually transmitted infections.

The participants received testing for the three STIs at weeks 12, 24, 36 and 48, when they also completed questionnaires about their number of recent sexual partners, condom use and drug use.

Those who took the antibiotic PrEP were 73 percent less likely to have contracted any of the three STIs by week 48 as those in the financial incentive group. Due in part to the small number of participants, the reduction in risk had a very wide estimate range, however: 17 percent to 91 percent.

The researchers concluded that their findings support the development of a larger trial to test the effectiveness of antibiotic PrEP for STIs.

To read the aidsmap story, click here.

To read the study abstract, click here.