NCT07500415 Doxi-Rio: Study on the Use of Doxycycline to Prevent Sexually Transmitted Infections in Rio de Janeiro
| NCT ID | NCT07500415 |
| Status | Recruiting |
| Phase | — |
| Sponsor | Oswaldo Cruz Foundation |
| Condition | Sexually Transmitted Diseases |
| Study Type | INTERVENTIONAL |
| Enrollment | 200 participants |
| Start Date | 2025-10-28 |
| Primary Completion | 2027-10 |
Eligibility & Interventions
Eligibility Fast-Check
Enter your details for a quick preliminary check. This does not replace medical advice.
What to Expect as a Participant
You will actively receive the study intervention — which may be a drug, biologic, device, or procedure.
This trial targets 200 participants in total. It began in 2025-10-28 with a primary completion date of 2027-10.
⚠ This information is for research awareness only. Always consult your physician before joining any clinical trial. Participation is voluntary and you may withdraw at any time.
Brief Summary
The goal of this clinical trial is to learn if doxycycline post-exposure prophylaxis (doxy-PEP) can help prevent bacterial sexually transmitted infections (STIs) among sexual and gender minorities in Rio de Janeiro, Brazil, including men who have sex with men, transgender women, and travestis who are living with HIV or using HIV pre-exposure prophylaxis (PrEP). Bacterial STIs such as syphilis, gonorrhea, and chlamydia remain common in these populations, even with existing prevention strategies. This study aims to answer the following questions: whether doxy-PEP can reduce the number of new STIs, whether it is safe and well tolerated, whether participants use it as recommended, and whether its use may contribute to antibiotic resistance or changes in the body's natural bacteria. Doxy-PEP involves taking a dose of doxycycline, an antibiotic, shortly after sexual activity to reduce the risk of acquiring STIs. Participants will first receive information and counseling about doxy-PEP, including its possible benefits and risks, and will then choose whether or not to use this prevention strategy. Those who choose to use doxy-PEP will take doxycycline after sex as instructed and will be followed for up to 48 weeks, with clinic visits approximately every three months. During these visits, participants will be tested for STIs, monitored for side effects, and asked about medication use, sexual health, and overall well-being. Researchers will collect information on new STI diagnoses, safety, and how consistently participants use doxy-PEP. The study will also explore participants' experiences and perceptions of this strategy. The results of this study will help determine whether doxy-PEP is a practical and acceptable approach for STI prevention in Brazil and may inform future public health strategies.
Eligibility 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
Contact & Investigator
Frequently Asked Questions
Who can join the NCT07500415 clinical trial?
This trial is open to participants of all sexes, aged 18 Years or older, studying Sexually Transmitted Diseases. Full inclusion and exclusion criteria are listed in the Eligibility Criteria section. Always confirm your eligibility with the research team before applying.
Is NCT07500415 currently recruiting?
Yes, NCT07500415 is actively recruiting participants. Contact the research team at beatriz.grinsztejn@gmail.com for enrollment information.
Where is the NCT07500415 trial being conducted?
This trial is being conducted at Rio de Janeiro, Brazil.
Who is sponsoring the NCT07500415 clinical trial?
NCT07500415 is sponsored by Oswaldo Cruz Foundation. The trial plans to enroll 200 participants.