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Completed Phase 4 Interventional Accepts healthy volunteers Results available

Evaluation of Doxycycline Post-exposure Prophylaxis to Reduce Sexually Transmitted Infections in PrEP Users and HIV-infected Men Who Have Sex With Men

ClinicalTrials.gov ID: NCT03980223

Public ClinicalTrials.gov record NCT03980223. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.

ClinicalTrials.gov public records Last synced Sep 5, 2026, 12:35 PM EDT

Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.

Brief summary

Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.

The purpose of this study is to understand if taking an antibiotic called doxycycline by mouth as soon as possible after sexual contact without a condom can reduce the risk of sexually transmitted infections (STIs), including gonorrhea, chlamydia and syphilis. The study will also look at the safety of doxycycline PEP and the impact that PEP may have on the bacteria that cause STIs as well as on bacteria that normally live on the body. While doxycycline is approved by the Food and Drug Administration (FDA), taking doxycycline immediately after sexual contact to prevent infection is investigational and is not approved by the FDA for this use. Participants will take part in the study for 1 year.

Study identification

NCT ID
NCT03980223
Recruitment status
Completed
Study type
Interventional
Phase
Phase 4
Enrollment
641 participants

Conditions and interventions

Eligibility (public fields only)

Age range
18 Years and older
Sex
Male
Healthy volunteers
Accepts healthy volunteers

This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.

Study timeline

Start date
Nov 25, 2019
Primary completion
Jun 11, 2023
Completion
Jun 11, 2023
Last update posted
Jul 11, 2024

2019 – 2023

United States locations

U.S. sites
3
U.S. states
2
U.S. cities
2
Facility City State ZIP Site status
San Francisco City Clinic / San Francisco Department of Public Health San Francisco California 94103
University of California, San Francisco / Zuckerberg San Francisco General Hospital/UCSF San Francisco California 94110
University of Washington Seattle Washington 98195

Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.

About this trial record page

What this page shows
Public field values for ClinicalTrials.gov record NCT03980223, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
What this page does not do
No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
Where the data comes from
Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
Last refresh
Last update posted Jul 11, 2024 · Synced Sep 5, 2026

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Open the official record

The complete protocol, eligibility criteria, and contact information for NCT03980223 live on ClinicalTrials.gov.

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