Effectiveness of GABA Agonists in Reducing the Reinforcing Effects of Cocaine

January 10, 2017 updated by: National Institute on Drug Abuse (NIDA)

GABA Agonists as Pharmacotherapies for Cocaine Abuse

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.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

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.

Study Type

Interventional

Enrollment (Actual)

78

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Kentucky
      • Lexington, Kentucky, United States, 40536 0086
        • University of Kentucky Medical Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

16 years to 48 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Recent use of cocaine
  • Meets DSM-IV diagnostic criteria for psychoactive substance abuse or dependence for cocaine
  • Positive drug urine screen for cocaine at time of initial screening interview
  • Reports self-administration of at least 1,260 mg of cocaine during the 4 weeks prior to study start date
  • Body Mass Index (BMI) of less than 29
  • Females must use an effective form of contraception throughout the study

Exclusion Criteria:

  • Meets DSM-IV diagnostic criteria for psychoactive substance dependence for substances other than cocaine or nicotine
  • Currently seeking treatment for substance abuse/dependence
  • Current or past history of physical disease, impaired cardiovascular functioning, chronic obstructive pulmonary disease
  • History of seizure, head traumas, or central nervous system tumors
  • Current or past history of serious psychiatric disorder other than substance abuse or dependence
  • Family history of cardiovascular disease or seizure disorders

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Single Group Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
No Intervention: A
Within subject design
Drug: GABA Agonists
GABA drugs administered acutely by mouth
Other Names:
  • Triazolam, tiagabine, baclofen

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Progressive-ratio break point
Time Frame: Measured during each experimental session
Measured during each experimental session

Secondary Outcome Measures

Outcome Measure
Time Frame
Subjective effects of cocaine
Time Frame: Measured during each experimental session
Measured during each experimental session
Physiological measures
Time Frame: Measured throughout the study
Measured throughout the study

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Institute on Drug Abuse (NIDA)

Investigators

  • Principal Investigator: Craig Rush, ACT

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

August 1, 2001

Primary Completion (Actual)

May 1, 2005

Study Completion (Actual)

May 1, 2005

Study Registration Dates

First Submitted

September 16, 2005

First Submitted That Met QC Criteria

September 16, 2005

First Posted (Estimate)

September 22, 2005

Study Record Updates

Last Update Posted (Estimate)

January 11, 2017

Last Update Submitted That Met QC Criteria

January 10, 2017

Last Verified

October 1, 2016

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • DA013567
  • DPMC (Other Identifier: NIDA)
  • R01-13567-1

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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