Which antibiotic works best for hidden anal chlamydia?
NCT ID NCT03532464
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study compared two common antibiotics—azithromycin (single dose) and doxycycline (7-day course)—for treating anal chlamydia in women who also had a vaginal chlamydia infection. The goal was to see which treatment clears the anal infection better, since anal chlamydia often goes unnoticed and can lead to repeat infections. The trial enrolled 460 women and used a DNA test to check if the infection was gone after treatment.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- azithromycin and doxycycline
- What this could lead to
- If this trial succeeds, it could show which antibiotic works better for anorectal chlamydia, helping prevent repeat infections and complications like infertility.
- What could go wrong
- This is a completed Phase 4 trial, but results may not apply to all populations. Both drugs are already approved, so the benefit is limited to treatment choice rather than a breakthrough.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 4
Runs after approval, following long-term safety and how well the treatment works in everyday use.
- Participants
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460 people
The number who actually took part.
- Started
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Oct 2018
- Finished
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Aug 2020
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 years and older
- Sex
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Female participants only
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: * Female * Age \> 18 years * Negative β-hCG urinary assay and efficacious contraception for participant consulting in specialist centre * Participant requesting an abortion at a pregnancy termination centre and efficacious contraception after abortion * C. trachomatis-positive test for vaginal specimen using a Nucleic Acid Amplification Test (NAAT) * Sexually active * Consultation in one of the participating centers * Agree to be contacted for follow-up * Member or beneficiary of a social security system * Free written informed consent signed by the participant and the investigator (no later than the inclusion day and before performing any examination required for the study) Exclusion Criteria: * Women who have symptoms suggesting pelvic inflammatory disease (PID) * Receipt of an antibiotic with antichlamydial activity within 21 days before screening or between screening and enrollment * Contraindications to tetracyclines, macrolides or ketolids (including allergy and treatment with colchicine, cisapride, ergot alkaloids and retinoids) * Inability to swallow pills * Refusal to participate in the study * Objectives of the study not understood. * Breast-feeding * Patients with serious cardiac diseases: documented prolongation of the QT tract of the ECG, cardiac arrhythmias, advanced heart failure (classification New York Heart Association or NYHA \>III) * Patients treated with anticoagulants or drug with a definite potential of "Torsades de Pointe" or prolongation of the QT tract of the electrocardiogram * Patients with severe liver diseases
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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CHRU Tours
Tours, 37000, France
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CHU de Bordeaux
Bordeaux, 33000, France
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CHU de Nantes
Nantes, 44000, France
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CeGGID - Bordeaux
Bordeaux, 33000, France
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CeGIDD - Marseille
Marseille, Marignane, 13700, France
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Hôpital Hôtel Dieu
Paris, 75004, France
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Hôpital de Roubaix
Roubaix, 59170, France
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