Effectiveness of GABA Agonists in Reducing the Reinforcing Effects of Cocaine
Condition: Cocaine-Related Disorders
MeSH terms: Cocaine-Related Disorders
Study type: Interventional
Phase: Phase 2

Summary: 
      Cocaine abuse continues to represent a significant public-health concern. Cocaine likely
      creates its addictive effects by increasing levels of dopamine, a chemical found in the
      brain. GABA agonists are chemicals that have the opposite effect of cocaine by inhibiting the
      release of dopamine. The purpose of this study is to determine whether GABA agonists reduce
      the psychological and physiological reinforcing effects of cocaine.
    

Detailed description: 
      Cocaine likely creates its reinforcing and addictive effects by increasing levels of
      dopamine, a brain neurotransmitter. GABA agonists are chemicals that have the opposite effect
      by inhibiting the release of dopamine. Increasing GABA activity may result in greater
      inhibition of dopamine systems, which may lead to new treatments for cocaine abuse. The
      purpose of this study is to determine whether pretreatment with GABA agonists reduces the
      psychological and physiological reinforcing effects of cocaine. Specifically, the study will
      look at three different GABA agonists: tiagabine, baclofen, and trazolam.

      This double-blind, placebo-controlled study will involve three separate experimental phases;
      each phase will last 4 weeks and will test one of three GABA agonists (tiagabine, baclofen,
      or trazolam). Daily testing sessions will last approximately 6 hours. One of four GABA
      agonist dose treatments will be administered. Participants will then be introduced to a
      sample dose of intranasal cocaine. This will allow the participants to become acquainted with
      the drug effects of the corresponding cocaine dose for that day (0.444, 5, 10, or 20 mg).
      Subjective, physiological, and performance measures will be obtained. This will be followed
      by a period of cocaine self-administration. Participants will be given the opportunity to
      work on a computer to obtain additional single unit doses of cocaine. A total of 8 unit doses
      of cocaine will be available during each daily session. At the end of the daily session,
      additional subjective measures will be evaluated with questionnaires. Overall, a total of 16
      GABA agonist-cocaine dose combinations will be administered on 16 different days. A subgroup
      of participants will also undergo similar procedures with the option to acquire money instead
      of cocaine. At the end of the study, all participants will be offered a referral to an
      appropriate drug-abuse treatment program.
    

Intervention name(s): GABA Agonists
Intervention type(s): Drug
Intervention description(s): GABA drugs administered acutely by mouth
Other intervention name(s): Triazolam, tiagabine, baclofen
Intervention MeSH terms: Triazolam; Tiagabine; Baclofen; GABA Agonists
Allocation: Randomized
Intervention model: Single Group Assignment
Masking: Double (Participant, Care Provider)
Primary purpose: Treatment
Keywords: cocaine; tiagabine; baclofen