CI

At a glance

ClinicalIndex Comparison Record
Phase 2Completed· 60 enrolled
Drug / intervention
Naltrexone Hydrochloride +2 moredrug
Likely dose
Naltrexone Hydrochloride 50 mgfrom record
Structured eligibility isn't available for this trial yet — see the full criteria in the Eligibility tab below.

Standardized by ClinicalIndex from the ClinicalTrials.gov record · verify against the source.

Search/NCT04791969
NCT04791969Phase 2Completed

The ION+EMI Study: Intermittent Oral Naltrexone Enhanced With an Ecological Momentary Intervention for Methamphetamine-using MSM

Glenn-Milo Santos·interventional·Posted Mar 10, 2021·Updated Oct 27, 2025

In Brief

A Phase 2 clinical trial evaluating Naltrexone Hydrochloride, Placebo, and 1 other intervention for Methamphetamine Use Disorder. Completed, enrolled 60 participants across 1 site.

Detailed Summary

This is a double-blind, placebo-controlled phase 2b trial in which 54 MSM who use meth will be randomly assigned (2:1) to receive 12 weeks of as-needed intermittent oral naltrexone 50 mg enhanced with an EMA-informed EMI platform, or receive as-needed placebo with EMA-informed EMI. The 12-week treatment period is consistent with other pharmacotherapy trials for substance use disorders. The proposed sample size is also consistent with other phase 2b trials for substance use treatment. Upon enrollment, participants will complete daily EMA assessments and weekly visits for behavioral surveys and urine testing for meth metabolites, study drug dispensing and computer-based counseling for substance use. Safety laboratory assessments and vital signs will be completed monthly. Efficacy (Specific Aims 1-3) will be assessed upon trial completion as measured by proportion meth-positive urine samples; PrEP and ART adherence by drug levels and viral load testing; and sexual risk behavior data accounting for PrEP use and viral suppression.

Study Details

Study Typeinterventional
Allocation--
Masking--
Primary Purpose--
CountriesUnited States

Timeline

Phase 2CompletedFinished
20222023202420252026
First PostedMar 10, 2021
Enrollment StartDec 14, 2021
Primary CompletionMar 1, 2024
Study CompletionJul 1, 2024
TodayJul 2, 2026
Enrollment to primary: 2.2 yearsPosted 5.3 years ago

Interventions

Naltrexone Hydrochloridedrug

Intermittent Oral Naltrexone, 50 mg

Placebodrug

Intermittent Oral Placebo

Ecological Momentary Interventionbehavioral

Receive ecological momentary intervention if ecological momentary assessment reports meth craving, stress, not taking study drug, or antecedents detected for "high risk" meth use.