Naltrexone for Overdose Prevention

Q: Who can participate in NCT06633900?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

Q: How do I contact the trial site for NCT06633900?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Q: Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Q: Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

Extended-Release Naltrexone as Opioid Overdose Pre-Exposure Prophylaxis (PrEP) in People Using Stimulants Living With or At Risk of HIV

Naltrexone for Overdose Prevention (NCT06633900) is a Phase 2 / Phase 3 interventional studying Overdose Accidental, sponsored by University of California, San Francisco. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

The goal of this clinical trial is to see if an injectable medicine called naltrexone can prevent fentanyl overdose deaths in people who use other drugs (cocaine, methamphetamine). The main questions it aims to answer are: What are the challenges for implementing naltrexone as an overdose prevention strategy? Are injections of naltrexone effective for opioid overdose prevention among people who use stimulants? How often are people who use stimulants and do not intentionally use opioids unintentionally exposed to opioids? Researchers will compare participants to receive the study medication to the usual care group to see if one group experiences fewer opioid overdose events than the other. Participants will be randomized to either receive a monthly injection of naltrexone over six months, or receive usual care. Usual care includes harm reduction supplies. Laboratory procedures will include the collection of urine, blood, and hair samples for various safety and outcome measure testing.

What Stage of Research Is This?

Phase 2 trials evaluate whether a treatment actually works against Overdose Accidental and continue monitoring side effects. Phase 2 enrolls larger groups (typically 100–300 patients) and produces the first real efficacy signal. A successful Phase 2 readout is what unlocks the much larger Phase 3 confirmatory trials needed for FDA approval.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

Target enrollment of 100 participants puts this in the typical range for a Phase 2-style efficacy study or a moderate Phase 3 trial in a focused Overdose Accidental subpopulation. At this scale, the study has enough statistical power to detect a clear treatment effect but is not the largest cohort in the field.

Who May Be Eligible (Plain English)

Who May Qualify: 1. at-risk for HIV or living with HIV 2. stimulant use disorder (by DSM-V) or positive urine drug test for cocaine, amphetamine, or methamphetamine in last 6 months AND report at least 10 days of stimulant use/month, 3. able to provide willing to sign a consent form, 4. English-speaking, 5. age 18 years old or greater. Who Should NOT Join This Trial: 1. prescribed or non-prescribed opioid use (including newly diagnosed opioid use disorder by DSM-V), 2. receipt of long-acting injectable naltrexone for other indications in past 30 days, 3. planned surgery in next 6 months, 4. moderate, severe or chronic liver disease (AST, ALT ≥ 5 times the upper limit of normal or symptoms of current liver disease), 5. persons who are pregnant or breastfeeding, 6. increased risk of bleeding (thrombocytopenia \<50 x 109/L, coagulopathy, or therapeutic anticoagulation), 7. known hypersensitivity to naltrexone or its diluents, or 8. any other reason (e.g. comorbid medical conditions, adherence concerns, lack of interest in naltrexone, etc.) that judged by the study team's discretion, would impede the participant from successfully completing the trial. Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

Inclusion Criteria: 1. at-risk for HIV or living with HIV 2. stimulant use disorder (by DSM-V) or positive urine drug test for cocaine, amphetamine, or methamphetamine in last 6 months AND report at least 10 days of stimulant use/month, 3. able to provide informed consent, 4. English-speaking, 5. age 18 years old or greater. Exclusion Criteria: 1. prescribed or non-prescribed opioid use (including newly diagnosed opioid use disorder by DSM-V), 2. receipt of long-acting injectable naltrexone for other indications in past 30 days, 3. planned surgery in next 6 months, 4. moderate, severe or chronic liver disease (AST, ALT ≥ 5 times the upper limit of normal or symptoms of current liver disease), 5. persons who are pregnant or breastfeeding, 6. increased risk of bleeding (thrombocytopenia \<50 x 109/L, coagulopathy, or therapeutic anticoagulation), 7. known hypersensitivity to naltrexone or its diluents, or 8. any other reason (e.g. comorbid medical conditions, adherence concerns, lack of interest in naltrexone, etc.) that judged by the study team's discretion, would impede the participant from successfully completing the trial.

Treatments Being Tested

DRUG

IM naltrexone

The study drug is an intramuscular injection of naltrexone (380mg), administered every 4 weeks via an injection in the ventrogluteal region.

BEHAVIORAL

Usual Care

Participants assigned to usual care will receive a harm reduction bundle in clinic. It will include the following components: 1) intranasal naloxone 4mg x 2, 2) participant choice of safer consumption kits based on substances and route used (specific materials for inhaled use vs. injecting, based on common use practices in the region), 3) fentanyl test kits with 2 lateral flow assays per package along with instructions to minimize false positive results, and 4) information about universal overdose precautions (behavioral modifications to optimize safety like using in the presence of others, use a test dose of new substances, etc.)

Locations (1)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

Center on Substance Use and Health

San Francisco, California, United States

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT06633900), the sponsor (University of California, San Francisco), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT06633900 clinical trial studying?

The goal of this clinical trial is to see if an injectable medicine called naltrexone can prevent fentanyl overdose deaths in people who use other drugs (cocaine, methamphetamine). The main questions it aims to answer are: What are the challenges for implementing naltrexone as an overdose prevention strategy? Are injections of naltrexone effective for opioid overdose prevention among people who use stimulants? How often are people who use stimulants and do not intentionally use opioids unintentionally exposed to opioids? Researchers will compare participants to receive the study medication… The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Who can participate in NCT06633900?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT06633900?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT06633900. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT06633900. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-06-26 · Data from ClinicalTrials.gov.