Could a single antibiotic dose after sex stop STIs?

NCT ID NCT07397403

Recruiting now Prevention Sponsor: Bangrak STIs Center Source: ClinicalTrials.gov ↗

First seen Jun 26, 2026 · Last updated Jun 27, 2026 · Updated 1 time

Summary

This study tests whether taking a single 200 mg dose of doxycycline within 24–72 hours after unprotected sex can prevent gonorrhea, chlamydia, and syphilis in men who have sex with men. Researchers in Bangkok will enroll 400 participants and follow them for 12 weeks. If effective, this could offer a new prevention tool for high-risk individuals.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance: doxycycline
What this could lead to: If it works, this could provide a simple, on-demand pill to reduce the risk of common sexually transmitted infections in high-risk groups.
What could go wrong: This is a single-site trial in Thailand, so results may not apply elsewhere. Doxycycline may not prevent all STIs, and overuse could lead to antibiotic resistance.

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Conditions

The condition(s) this trial relates to.

chlamydia infectious disease chlamydia trachomatis infectious disease prevention target gonorrhea prevention target syphilis prevention target

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

CHLAMYDIA GONORRHEA SYPHILIS INFECTION

Contacts and locations

Locations

Bangrak STIs Center
RECRUITING

Sathorn, Bangkok, 10120, Thailand

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