Doxycycline post-exposure prophylaxis (Doxy-PEP) in Czech clinical practice: a review of efficacy, safety, and implications for antimicrobial resistance

Doxycycline post-exposure prophylaxis (Doxy-PEP; a single 200 mg dose of doxycycline within 72 hours after sexual exposure, not exceeding 200 mg per 24 hours) has been shown in randomized trials among men who have sex with men (MSM) and transgender women (TGW) to reduce the incidence of syphilis and Chlamydia trachomatis infection; its effect on Neisseria gonorrhoeae transmission is smaller and varies by locale. In 2024, the U.S. Centers for Disease Control and Prevention (CDC) published the first clinical guidance recommending targeted use of Doxy-PEP for MSM/TGW with a bacterial sexually transmitted infection (STI) in the previous 12 months; European branch of International Union Against Sexually Transmitted Infectuions (IUSTI-Europe) in June 2024 acknowledged individual benefits while urging caution; and in 2025 the World Health Organization initiated development of global guidance. To provide a clinically oriented review of the effectiveness, safety, and risks of Doxy-PEP and to place these findings within the Czech context of epidemiology and antimicrobial resistance, including interpretation of the national position statement of the Society for Infectious Medicine (SIL ČLS JEP). Doxy-PEP is an effective tool for preventing syphilis and Chlamydia trachomatis infection in high-risk MSM/TGW. Given potential adverse effects, the risk of antimicrobial resistance (AMR) development, and the still limited data for other populations, cautious, data-driven use within comprehensive sexual health care is advisable. This approach is consistent with international recommendations and the current SIL ČLS JEP position statement.