Actively Recruiting
Doxi-Rio: Pilot Implementation of Post-exposure Prophylaxis for Sexually Transmitted Infections With Doxycycline in Rio de Janeiro, Brazil
Led by Oswaldo Cruz Foundation · Updated on 2026-03-30
200
Participants Needed
1
Research Sites
30 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
Researchers are evaluating whether doxycycline post-exposure prophylaxis (doxy-PEP) can help prevent bacterial sexually transmitted infections (STIs) among sexual and gender minorities in Rio de Janeiro, Brazil. This includes men who have sex with men, transgender women, and travestis living with HIV or using HIV pre-exposure prophylaxis (PrEP). The study aims to determine if doxy-PEP reduces new STI cases, is safe and well tolerated, is used as recommended, and whether it affects antibiotic resistance or natural bacteria in the body. Participants who decide to use doxy-PEP will take a dose of doxycycline orally within 72 hours after sexual activity, not exceeding one dose per 24 hours and a maximum of three doses per week. After counseling about risks and benefits, participants will be followed for up to 48 weeks with clinic visits approximately every three months. Those who initially decline doxy-PEP may start it later during the study. During visits, participants will be tested for STIs, monitored for side effects, and asked about medication use, sexual health, and well-being. Researchers will collect data on new STI diagnoses, safety, adherence to doxy-PEP, and participants' experiences. This information will help decide if doxy-PEP is a practical prevention approach in Brazil and guide future public health strategies.
CONDITIONS
Brief Title
Doxi-Rio: Study on the Use of Doxycycline to Prevent Sexually Transmitted Infections in Rio de Janeiro
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Individuals assigned male at birth (cisgender or transgender men), transgender women, or travestis who have sex with men
- Age 18 years or older
- 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
You will not qualify if you...
- 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
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 visit (in-person)
Duration - Up to 48 weeks
Participants take doxycycline 200 mg orally within 72 hours after sexual activity as post-exposure prophylaxis to prevent sexually transmitted infections. Participants receive counseling on risks and benefits and can start doxycycline at any time during the study.
Regular clinical visits including testing for sexually transmitted infections, safety assessments, and adherence evaluation
Trial Site Locations
Total: 1 location
1
Instituto Nacional de Infectologia Evandro Chagas
Rio de Janeiro, Rio de Janeiro, Brazil, 21040-360
Actively Recruiting
Research Team
B
Beatriz Grinsztejn, PhD
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NA
Model
SINGLE_GROUP
Primary Purpose
TREATMENT
Number of Arms
1
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