Doxycycline to prevent bacterial STIs in sexual and gender minorities in Rio de Janeiro.
Doxi-Rio: Pilot Implementation of Post-exposure Prophylaxis for Sexually Transmitted Infections With Doxycycline in Rio de Janeiro, Brazil
This research will try taking doxycycline after sex to see if it lowers the chance of syphilis, gonorrhea, and chlamydia for men who have sex with men, transgender women, and travestis in Rio de Janeiro who are living with HIV or using PrEP.
Quick facts
| Phase | Not applicable |
|---|---|
| Study type | Interventional |
| Enrollment | 200 (estimated) |
| Ages | 18 Years and up |
| Sex | All |
| Sponsor | Oswaldo Cruz Foundation Academic / other |
| Locations | 1 site (Rio de Janeiro, Rio de Janeiro) |
| Trial ID | NCT07500415 on ClinicalTrials.gov |
What this trial studies
This interventional trial tests doxycycline post-exposure prophylaxis (doxy-PEP) taken shortly after sexual activity among sexual and gender minorities in Rio de Janeiro, including men who have sex with men, transgender women, and travestis who are living with HIV or using PrEP. Participants receive counseling about doxy-PEP and are instructed on when to take a dose after potential exposures, with regular clinic visits for symptom checks and laboratory STI testing. The study tracks new cases of syphilis, gonorrhea, and chlamydia as primary outcomes, and also monitors safety, adherence, and potential effects on antibiotic resistance and the body’s normal bacterial flora. People with doxycycline allergy or taking contraindicated medications are excluded.
Who should consider this trial
Good fit: Adults (≥18) assigned male at birth, transgender women, or travestis who have sex with men, are living with HIV or have used PrEP for at least six months, and who had at least one bacterial STI in the past 12 months are the intended candidates.
Not a fit: People with a known allergy to doxycycline, those taking contraindicated medications, or individuals who are not in the specified populations or who lack a recent STI history are unlikely to benefit from participation.
Why it matters
Potential benefit: If successful, doxy-PEP could substantially reduce rates of bacterial STIs in these high-risk communities.
How similar studies have performed: Previous trials among men who have sex with men have shown doxy-PEP can substantially reduce bacterial STIs, though those studies have also raised concerns about potential antimicrobial resistance.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: * Individuals assigned male at birth (cisgender or transgender men), transgender women, or travestis who have sex with men * Age ≥18 years * Living with HIV or currently using HIV pre-exposure prophylaxis (PrEP) for at least 6 months * History of at least one bacterial sexually transmitted infection (chlamydia, gonorrhea, or syphilis) in the past 12 months (laboratory-confirmed or self-reported) * Willing and able to provide informed consent Exclusion Criteria: * Known allergy or hypersensitivity to doxycycline or other tetracycline-class antibiotics * Current use of medications that may significantly interact with doxycycline or are contraindicated, including systemic retinoids, barbiturates, carbamazepine, or phenytoin
Where this trial is running
Rio de Janeiro, Rio de Janeiro
- Instituto Nacional de Infectologia Evandro Chagas — Rio de Janeiro, Rio de Janeiro, Brazil (Recruiting)
Study contacts
- Study coordinator: Beatriz Grinsztejn, PhD
- Email: beatriz.grinsztejn@gmail.com
- Phone: +55 2138659128
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.