DoxyPEP: what to know before talking to your doctor

DoxyPEP is getting a lot of attention. It means taking an antibiotic, doxycycline, after sex to reduce the risk of some bacterial STIs. Here are the essentials to understand what it is, and why it should always be discussed with a doctor.

How it works

DoxyPEP (doxycycline post-exposure prophylaxis) means taking a single dose of doxycycline, usually 200 mg, ideally within 24 hours and no later than 72 hours after condomless sex.

It targets bacterial STIs: syphilis, chlamydia and gonorrhoea. It has no effect on HIV, hepatitis, HPV, herpes or mpox.

What studies show

Several trials, mainly among men who have sex with men and trans women — including the DoxyPEP trial in the United States and the ANRS DOXYVAC trial in France — found:

• a sharp drop in syphilis and chlamydia infections;
• a more modest effect on gonorrhoea, many strains of which already resist this class of antibiotics.

Limits to keep in mind

• Antibiotic resistance: repeated antibiotic use can encourage resistant bacteria, in the individual and in the population. This is the main reason health authorities are cautious.
• Side effects: digestive issues, increased sun sensitivity, possible effects on the microbiome.
• Contraindications: notably pregnancy, and some drug interactions.
• Not complete protection: it does not replace condoms, PrEP or regular testing.

What health authorities say

In the United States, the CDC has recommended since 2024 that DoxyPEP be offered to men who have sex with men and trans women who have had a bacterial STI in the past year.

In France, as of this article’s last update, DoxyPEP is not recommended for general use. It may be considered case by case with a doctor, taking into account your exposure and the risk of antibiotic resistance. Guidance differs between countries, so check with your local sexual health services.

In practice, if it is prescribed

• stick to the dose and timing your doctor gives you, without extra doses;
• swallow the pill with a large glass of water while sitting or standing;
• protect yourself from the sun;
• keep up regular testing, since DoxyPEP does not prevent every infection.

Organising reminders with heatmeUp

In the health module, you can create a DoxyPEP or treatment reminder with a start and end date, and keep track of your tests. The app never advises on dosage: it simply helps you stay organised, without anything leaving your phone.

---

Sources

1. Centers for Disease Control and Prevention (CDC) — Doxycycline post-exposure prophylaxis guidelines (2024)
2. ANRS | Emerging Infectious Diseases — DOXYVAC trial
3. World Health Organization (WHO) — Sexually transmitted infections

ⓘ This guide is for information only and does not replace medical advice. If in doubt, talk to a healthcare professional.