Doxi-Rio: Study on the Use of Doxycycline to Prevent Sexually Transmitted Infections in Rio de Janeiro
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: Doxycycline.
- Who it may be relevant to
- Registry conditions: Sexually Transmitted Diseases, Syphilis, Gonorrhea, Chlamydia Infections. Basic parameters: from 18 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Brazil
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Official title
Doxi-Rio: Pilot Implementation of Post-exposure Prophylaxis for Sexually Transmitted Infections With Doxycycline in Rio de Janeiro, Brazil
Overview
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.
Interventions
- Drug Doxycycline
Doxycycline 200 mg taken orally within 72 hours after sexual activity, not exceeding one dose per 24 hours and a maximum of three doses per week.
Primary outcome measures
- Incidence of bacterial sexually transmitted infections (STIs) [Time frame: Up to 48 weeks]
Secondary outcome measures (8)
- Incidence of symptomatic and asymptomatic bacterial STIs [Time frame: Up to 48 weeks.]
- Incidence of specific STIs (chlamydia, gonorrhea, and syphilis) [Time frame: Up to 48 weeks]
- Antimicrobial resistance in Neisseria gonorrhoeae [Time frame: Baseline and up to 48 weeks]
- Colonization with antimicrobial-resistant bacteria [Time frame: Baseline and week 48]
- Adverse events [Time frame: From enrollment to 48 weeks]
- Adherence to doxy-PEP [Time frame: Up to 48 weeks]
- Uptake of doxy-PEP [Time frame: At enrollment]
- Acceptability of doxy-PEP [Time frame: Up to 48 weeks]
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
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: Yes
Study design
- Allocation
- N/A
- Model
- Single group
- Masking
- Open label
- Primary purpose
- Treatment
Study locations
Brazil · 1 center
- Instituto Nacional de Infectologia Evandro Chagas — Rio de Janeiro
Identifiers
NCT: NCT07500415 · 87288525.2.0000.5262