Doxy PEP

What is doxy PEP?

Doxycycline post-exposure prophylaxis (doxy PEP) means taking doxycycline 200 mg within 72 hours after sex to prevent a possible infection with syphilis, chlamydia, and gonorrhea. Studies show that doxy PEP is effective at reducing STIs and is recommended by CDC for certain populations. This page summarizes the clinical guidelines on the use of doxy PEP released by CDC in June of 2024.

Effectiveness of doxy PEP

  • Recent studies of the use of doxy PEP among men who have sex with men (MSM) and transgender women (TGW) demonstrated significant reductions in bacterial STI infections.
  • A randomized clinical trial found that people who were assigned doxycycline 100 mg daily had a 73% reduction in chlamydia and syphilis incidence compared with the control group.
  • Another study held a randomized clinical trial where participants either took a single dose of doxycycline 100 mg within 24 hours and no later than 72 hours after having condomless anal or oral sex, versus no medication. Participants who took doxy PEP had a decreased risk of getting chlamydia of 70% and syphilis of 73%.

Administration and dosage

  • Providers should write the prescription for self administration of the recommended dose of 200 mg of doxycycline to be taken as soon as possible within 72 hours after the patient had oral, vaginal, or anal sex.
  • The maximum dose is 200 mg every 24 hours.

Who should receive doxy PEP

Providers can recommend doxy PEP to MSM and TGW who:

  • Have had a bacterial STI in the past year, and
  • Have had condomless sex with at least 1 man or TGW in the past year.

Providers can also offer doxy PEP using shared decision-making to:

  • Men and TGW who, in the past year, had condomless sex with at least one man or TGW but not had a bacterial STI.
  • Transgender men (and other gender diverse patients assigned female sex at birth) who had condomless sex with at least one man or TGW in the past year.

Providers should use their clinical judgement to consider using doxy PEP in other populations not included in CDC recommendations (e.g., cisgender female sex workers).

Clinical services with doxy PEP

  • Doxy PEP should be offered along with risk reduction counseling, STI screening and treatment, and HIV care.
  • Patients who are prescribed doxy PEP should be tested for bacterial STIs every 3–6 months and HIV screening should be performed for HIV-negative MSM and TGW.