RCT | Doxycycline postexposure prophylaxis effective in preventing gonorrhea, chlamydia, and syphilis in MSM

Summary: In this open-label, randomized study involving 501 men who have sex with men (MSM) and transgender women, researchers investigated the effectiveness of postexposure doxycycline in preventing bacterial sexually transmitted infections (STIs), specifically gonorrhea, chlamydia, and syphilis. Participants with a previous STI in the past year, either taking preexposure prophylaxis (PrEP) against HIV or living with HIV, were randomly assigned to receive 200 mg of doxycycline within 72 hours after condomless sex or standard care without doxycycline. STI testing was performed quarterly, with the primary end point being the incidence of at least one STI per follow-up quarter.

Results demonstrated a significant reduction in STI incidence in both the PrEP and persons living with HIV cohorts who received doxycycline.  Overall, the combined incidence of these three STIs was lower by two thirds with doxycycline postexposure prophylaxis compared to standard care. The study also reported five grade 3 adverse events but no serious adverse events attributed to doxycycline. This finding supports the use of doxycycline postexposure prophylaxis among MSM with recent bacterial STIs.

Article: Postexposure Doxycycline to Prevent Bacterial Sexually Transmitted Infections – New England Journal of Medicine (link to abstract – $ for full-text)

Commentary: Doxycycline after sex found to reduce STI incidence in gay men, transgender women – CIDRAP

Commentary on Twitter

In an open-label, randomized study involving men who have sex with men, doxycycline use after high-risk sexual exposure reduced the incidence of sexually transmitted infections (chlamydia, gonorrhea, and syphilis). https://t.co/tYOj8FLEy2 pic.twitter.com/bzNyvwzYS7

— NEJM (@NEJM) April 5, 2023