Doxycycline Post-Exposure Prophylaxis (doxy-PEP) for the Prevention of Bacterial Sexually Transmitted Infections for Men Who Have Sex with Men and Transgender Women

Men who have sex with men (MSM) and transgender women are at high risk for both viral and bacterial sexually transmitted infection (STI). Significant efforts have been implemented to prevent transmission of viral STIs such as HIV and HPV, but little has been done for bacterial STIs.

Recently, the Centers for Disease Control and Prevention (CDC) finalized its guideline for the use of doxycycline postexposure prophylaxis (oxy-PEP) for preventing the acquisition and transmission of bacterial STIs namely syphilis, chlamydia, and gonorrhea.¹ Doxy-PEP was first presented in 2022 at the International AIDS Conference.² The data presented at the time showed that, in men who have sex with men with HIV or taking HIV pre-exposure prophylaxis, there was an approximately 70 to 80% reduced incidence of chlamydia, gonorrhea, and syphilis in participants that used doxy-PEP.² More recent evidence has replicated the findings.³ Reviews of the topic show a 60 to 85% reduction in the diagnosis of chlamydia, gonorrhea, and syphilis in MSM.⁴ The number needed to treat for this therapy seems to be around 2 to 4 patients to prevent 1 diagnosis of bacterial STI. Those in the treatment cohort generally tolerated the regimen well.

The CDC and many major Departments of Health, including New York City and Los Angeles, have included doxy-PEP into their STI guidelines. These guidelines recommend MSM and transgender women at high risk for bacterial STI or a recent history of bacterial STI infection should be offered doxy-PEP to prevent these infections.¹ Prescriptions of doxy-PEP should be provided to be self-administered orally within 72-hours of sexual intercourse at a dose of 200 mg of doxycycline and should not exceed a maximum dose of 200 mg daily.¹

Doxy-PEP has the potential to significantly reduce bacterial STI acquisition and transmission for MSM and transgender women. While additional research is needed to fully study this therapy, including resistance patterns to tetracycline medications, the current evidence is encouraging. Family physicians should discuss Doxy-PEP with their MSM and transgender women patients.