Doxy-PEP

What is currently known about the prevention of sexually transmitted infections

Doxy-PEP (Doxycycline Post-Exposure Prophylaxis) is a relatively new concept for the prevention of certain bacterial sexually transmitted infections (STIs). After a sexual risk event, doxycycline is taken once to reduce the risk of infection. International studies show promising results – however, not for all infections and not for all groups of people.

Learn how Doxy-PEP works, who it is currently recommended for, and what limitations this form of prevention has.

What is Doxy-PEP

Doxy-PEP refers to post-exposure prophylaxis with doxycycline after a sexual risk event. This involves taking a single dose of 200 milligrams of doxycycline as soon as possible after unprotected oral, vaginal, or anal intercourse – ideally within 24 hours, but no later than 72 hours. More than 200 milligrams should not be taken within 24 hours. In Austria, its use is currently outside of the approved indication (off-label use) and exclusively after individual medical advice.

The important thing is: Doxy-PEP is not intended for the treatment of an existing sexually transmitted infection; rather, it aims to reduce the risk of new infections with certain bacterial pathogens.

Doxy-PEP is effective against chlamydia and syphilis.

Based on current knowledge, the effectiveness of Doxy-PEP is primarily well-proven for syphilis and chlamydia infections. Several large randomised controlled trials show that doxycycline reduces the risk of:

• Syphilis by more than 70 %
• Chlamydia by more than 70 %
• Gonorrhoea at around 50 %

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However, the effectiveness against gonorrhoea is considerably less certain. The reason for this is regional differences in antibiotic resistance. In Austria, gonococci already frequently show resistance to tetracyclines. Therefore, according to the assessment of Austrian professional societies, reliable protection against gonorrhoea cannot be expected.

Doxy-PEP: Who is it suitable for?

There is currently no general recommendation for all people at sexual risk. According to the current recommendations of the US Centers for Disease Control and Prevention (CDC), Doxy-PEP may be particularly useful for the following groups of people, after shared medical decision-making:

• Men who have sex with men (MSM)
• Trans women
• Individuals diagnosed with a bacterial STI within the past twelve months

Doxy-PEP: Recommendations in Austria

The World Health Organization (WHO) also conditionally recommends Doxy-PEP for these groups and sees the greatest benefit in people with recurrent bacterial STIs, particularly syphilis. Austrian professional societies ÖAG and ÖGSTD currently recommend a more cautious approach. Doxy-PEP is primarily considered here for men who have sex with men, as well as trans women with HIV or on HIV PrEP – and even then, only after an individual risk-benefit assessment. For cis women, heterosexual men, trans men, and other population groups, the scientific evidence is currently insufficient to make a general recommendation.

What are the known risks and side effects?

Like all antibiotics, Doxycycline can cause side effects. The most common side effects include:

• Nausea and other gastrointestinal complaints
• increased skin sensitivity to light (photosensitivity)
• Irritation or inflammation of the oesophagus, particularly with insufficient fluid intake

Furthermore, professional societies are discussing possible long-term effects on the microbiome and the development of antibiotic resistance. These questions are currently being intensively investigated scientifically.

Doxy-PEP does not replace comprehensive STI prevention

Even though Doxy-PEP can significantly reduce the risk of certain bacterial infections, it does not replace other protective measures. Comprehensive prevention still includes:

• Condoms and safer sex strategies
• Regular STI tests
• Sexual health advice
• Vaccinations against preventable infections (e.g. HPV or Hepatitis)
• HIV PrEP or optimal HIV therapy, if medically indicated

International guidelines recommend screening for sexually transmitted infections before starting Doxy-PEP and regular check-ups – typically every three to six months.

Conclusion on Doxy-PEP

Doxy-PEP represents a promising new approach to preventing certain bacterial sexually transmitted infections. Currently, the greatest benefit is seen in men who have sex with men, as well as trans women with an increased risk of STIs. In Austria, its use is currently exclusively on a case-by-case basis following individual medical consultation and outside of approved indications. As questions regarding antibiotic resistance and long-term effects are not yet fully understood, Doxy-PEP should always be part of a comprehensive prevention strategy and be accompanied by regular medical check-ups.

Advice at the Johann Strauss Pharmacy in Vienna

Do you have questions about doxycycline, HIV PrEP, or the prevention of sexually transmitted infections? We offer discreet advice on medicines, their correct use, and general STI prevention measures. A doctor's consultation is required to decide on Doxy-PEP and the necessary medical follow-up.