Intermittent Naltrexone Among Polysubstance Users
Condition: Methamphetamine; Alcohol
Intervention: Intermittent Oral Naltrexone; Placebo
Intervention MeSH terms: Naltrexone
Phase: Phase 2
Study type: Interventional
Primary purpose: Prevention
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Enrollment: 30.0
Sex: Male
Minimum age: 18 Years
Maximum age: 70 Years
Healthy volunteers: Accepts Healthy Volunteers
Keywords: methamphetamine; alcohol; HIV; sexual behavior

Summary:

      Naltrexone, a µ-opioid receptor antagonist, is a promising agent for methamphetamine-using
      and binge-drinking men who have sex with men (MSM). Naltrexone has shown efficacy in reducing
      relapse to amphetamines and is FDA-approved for alcohol dependence. Oral naltrexone is
      inexpensive and has few toxicities but the standard daily regimen for naltrexone is
      problematic as patients forget to take the medication. Given the challenges in daily dosing,
      alternate regimen schedules have been proposed to increase efficacy and expand the population
      that may benefit from this pharmacologic agent. One approach is intermittent targeted
      administration of naltrexone, whereby individuals take the medication as-needed in
      anticipation of substance use or during periods of craving. Administration of naltrexone
      prior to exposure to amphetamines significantly attenuates craving and targeted naltrexone
      has shown efficacy in reducing heavy alcohol use. However, there have been no studies
      assessing intermittent targeted dosing of naltrexone among methamphetamine-using and
      binge-drinking MSM. Polysubstance use patterns are common among MSM, and studies among those
      who abuse more than one substance are urgently needed. The aims of this study are to
      determine whether targeted dosing of naltrexone is feasible, tolerable and acceptable among
      non-dependent methamphetamine-using and binge-drinking MSM.
    

Eligibility criteria:

        Inclusion Criteria:

          1. male gender or transgender male-to-female

          2. self-reported anal sex with men in the prior six months while under the influence of
             meth and/or alcohol

          3. self-reported meth use at least bi-weekly in the prior three months

          4. at least weekly binge drinking (five or more drinks on a single drinking session) in
             the prior three months

        4) interested in reducing meth use and/or binge drinking 5) HIV-negative by rapid test or
        medical record of HIV infection 6) no current acute illnesses requiring prolonged medical
        care 7) no chronic illnesses that are likely to progress clinically during trial
        participation 8) able and willing to provide informed consent and adhere to visit schedule
        9) age 18-70 years 10) baseline complete blood count (CBC), total protein, albumin,
        glucose, alkaline phosphatase, creatinine, blood urea nitrogen (BUN), and electrolytes
        without clinically significant abnormalities as determined by study clinician in
        conjunction with symptoms, physical exam, and medical history

        Exclusion Criteria:

          1. any psychiatric (e.g., depression with suicidal ideation) or medical condition that
             would preclude safe participation in the protocol

          2. known allergy or previous adverse reaction to naltrexone

          3. current use of or dependence on any opioids or a known medical condition which
             currently requires or may likely require opioid analgesics

          4. opioid-positive urine test at enrollment

          5. current cluster of differentiation 4 (CD4) count < 200 cells/mm3

          6. moderate or severe liver disease (aspartate aminotransferase, alanine
             aminotransferase, or total bilirubin > 3 times upper limit of normal)

          7. impaired renal function (creatinine clearance < 60 ml/min)

          8. currently participating in another research study

          9. meth or alcohol dependence as determined by Structured Clinical Interview for
             Diagnostic and Statistical Manual of Mental Disorders (SCID) criteria

         10. any condition that, in the principal investigator and/or study clinician's judgment
             interferes with safe participation or adherence to study procedures.

         11. unwillingness to provide minimum locator for information

         12. not having a cellular phone that can send or receive a text message

         13. plans to leave the Bay Area during study follow-up

         14. not comfortable speaking and reading English, enough to participate in a program in
             English