What is doxyPEP?
DoxyPEP is the use of doxycycline for post-exposure prophylaxis for prevention of three common bacterial STIs: chlamydia, syphilis, and gonorrhea. A sexually active person can take 200mg of doxycycline up to 72 hours after they have sex to prevent these STIs, but it’s more effective the sooner they take it.
How effective is doxyPEP?
DoxyPEP has led to reductions in chlamydia and syphilis ranging from 74-88% and 55-57% in gonorrhea.
Why prescribe doxyPEP?
- DoxyPEP offers another prevention tool for common bacterial STIs, even when having sex without condoms.
- Doxycycline is a well-known antibiotic healthcare providers have prescribed for more than 50 years. It is safe and side effects are generally mild.
- Patients can take doxyPEP only when they need it–it doesn’t require daily pills!
- Research trials and real world experience have proved doxyPEP is responsible for major reductions in STI transmission. (1,2)
Who should receive doxyPEP?
National guidelines recommend discussing doxyPEP especially with cisgender men who have sex with men (MSM) and trans women. Efficacy studies have focused primarily on anal and oral sex and are underway for vaginal/front hole sex.
If a patient outside of these groups is wanting doxyPEP, don’t stop the discussion! Clinical guidelines recommend shared decision-making with the patient whenever possible. Ask more about what kinds of sex they are having, if they have condomless sex or multiple partners, or if they’ve been diagnosed with STIs in the past.
Worried about drug resistance?
Doxycycline is safe to take daily if someone is having frequent sex— just as it’s already prescribed daily for other health conditions, such as acne. Researchers are still studying whether/how doxyPEP may affect the gut microbiome and antimicrobial resistance. One recent study showed that doxyPEP resulted in less antimicrobial exposure than regular STI treatment. (3)
Resources:
Clinical Guidance
- Clinical Guidelines for DoxyPEP | Centers for Disease Control &Prevention
- DoxyPEP Prescribing Guide | San Francisco City Clinic
Patient Education
- DoxyPEP 101 (English) | Building Healthy Online Communities
- DoxyPEP 101 (Spanish) | Building Healthy Online Communities
- Videos: Let’s talk about doxyPEP for STIs | Greater Than
- Videos: Hablemos de doxyPEP para las ITS | Greater Than
Footnotes
1 Luetkemeyer, et al (2023). Postexposure Doxycycline to Prevent Bacterial Sexually Transmitted Infections.
2 Molina, et al (2024). Doxycycline Prophylaxis and Meningococcal Group B Vaccine to Prevent Bacterial Sexually Transmitted Infections in France (ANRS 174 DOXYVAC): A Multicentre, Open-label, Randomised Trial with a 2 × 2 Factorial Design.
3 Raccagni, et al (2025). Antimicrobial Consumption Among Users of Doxycycline Post-Exposure Prophylaxis in Milan, Italy.
