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Effectiveness of Tiagabine for Cocaine Dependence in Methadone-Maintained Individuals - 1

This study has been completed.
Information provided by:
National Institute on Drug Abuse (NIDA) Identifier:
First received: August 4, 2005
Last updated: December 14, 2007
Last verified: December 2007

Many opioid-dependent individuals are also dependent on cocaine. Methadone is a widely used and effective method for treating opioid dependence. However, it is not effective in treating other drugs of abuse. The purpose of this study is to determine the effectiveness of another drug, tiagabine, for treating cocaine dependence in opioid-dependent individuals already receiving methadone treatment.

Condition Intervention Phase
Cocaine-Related Disorders
Opiate Dependence
Drug: Tiagabine
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Caregiver, Investigator)
Primary Purpose: Treatment
Official Title: Tiagabine for the Treatment of Cocaine Dependence in Methadone-Maintained Individuals

Resource links provided by NLM:

Further study details as provided by National Institute on Drug Abuse (NIDA):

Primary Outcome Measures:
  • Thrice weekly Urine toxicology [ Time Frame: 13 weeks ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Self reports of cocaine and opioid use. [ Time Frame: 13 weeks ] [ Designated as safety issue: No ]
  • Opioid withdrawal symptoms [ Time Frame: 13 weeks ] [ Designated as safety issue: No ]
  • Adverse events [ Time Frame: 13 weeks ] [ Designated as safety issue: Yes ]
  • cocaine craving [ Time Frame: 13 weeks ] [ Designated as safety issue: No ]

Enrollment: 80
Study Start Date: December 2004
Study Completion Date: April 2007
Arms Assigned Interventions
Experimental: 1
Drug: Tiagabine
The tiagabine group will start receiving tiagabine 4mg in the evening of the first day on week 2. The dose will be titrated every third day, until the target dose of 32mg/day is achieved by week 5. The study medication must be titrated to 32 mg/day or to the subject's maximum tolerated dose (MTD).
Other Name: Gabatril
Placebo Comparator: 2
Matching placebo
Drug: Tiagabine
The tiagabine group will start receiving tiagabine 4mg in the evening of the first day on week 2. The dose will be titrated every third day, until the target dose of 32mg/day is achieved by week 5. The study medication must be titrated to 32 mg/day or to the subject's maximum tolerated dose (MTD).
Other Name: Gabatril

Detailed Description:

For over 30 years, methadone has been used to treat opioid addiction. Since methadone is effective in reducing withdrawal symptoms, it is used as a method of detoxification for opiate addicts. However, methadone is not effective in treating other drugs of abuse, such as cocaine. Tiagabine is a drug that enhances levels of gamma aminobutyric acid (GABA), a chemical found in the brain and spinal cord. The objective of this study is to determine the effectiveness of tiagabine in modifying cocaine-using behavior and reducing opiate withdrawal symptoms among newly admitted methadone-treated patients.

This 16-week, double-blind, placebo-controlled clinical trial will involve 120 participants who are both cocaine- and opioid- dependent. Participants will be randomly assigned to receive either tiagabine or placebo, while concurrently receiving methadone treatment. Baseline cocaine use will be determined during the first two weeks of treatment. The study will include three overlapping phases. The first phase will include a one-week fixed methadone induction (Week 1), as well as flexible methadone stabilization (Weeks 2-13). Phase two will consist of a 12-week treatment period (Weeks 2-13). This will consist of tiagabine induction and stabilization. Phase three will include a 4-week taper, detoxification, or transfer period (Weeks 14-17). After completion of treatment, a 3-month follow-up visit will occur.


Ages Eligible for Study:   18 Years to 65 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Currently not enrolled in methadone-maintenance treatment
  • Demonstration of current opioid dependence as determined by the study physician, a self-reported history of opioid dependence for one year, and a positive urine test for opiates
  • Current cocaine abuser with self-reported use of cocaine at least 1 time each week within the month prior to study entry, positive urine screen for cocaine, and score greater than 3 on the Severity Dependence Scale
  • Women of childbearing age are eligible under the following conditions: negative pregnancy test at initial screening, adequate contraceptive use throughout the study, monthly pregnancy tests, and acknowledgement of fetal toxicity risks due to medication

Exclusion Criteria:

  • Current diagnosis of other drug or alcohol dependence (other than opiates, cocaine, or tobacco)
  • Serious medical illness (e.g., major heart, kidney, endocrine, or liver disease, or serious neurological disorders, including history of seizures)
  • Current diagnosis of a serious psychiatric illness or history of psychosis, schizophrenia, or bipolar type I disorder
  • Suicidal or homicidal thoughts
  • Currently taking psychotropic medications
  • Women who are pregnant, nursing, refuse to use a reliable form of contraception, or refuse monthly pregnancy testing
  • Greater than 3 times the normal level in liver screening function test (SGOT or SGPT)
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00129298

Sponsors and Collaborators
Principal Investigator: Gerardo Gonzalez, M.D. Yale University
  More Information

No publications provided

Responsible Party: Gerardo Gonzalez, MD, Yale University Identifier: NCT00129298     History of Changes
Other Study ID Numbers: NIDA-17782-1, R01-17782-1, DPMC
Study First Received: August 4, 2005
Last Updated: December 14, 2007
Health Authority: United States: Federal Government

Keywords provided by National Institute on Drug Abuse (NIDA):
cocaine abuse
opiate dependent

Additional relevant MeSH terms:
Cocaine-Related Disorders
Chemically-Induced Disorders
Mental Disorders
Substance-Related Disorders
Analgesics, Opioid
Anesthetics, Local
Antitussive Agents
Cardiovascular Agents
Central Nervous System Agents
Central Nervous System Depressants
Dopamine Agents
Dopamine Uptake Inhibitors
GABA Agents
GABA Agonists
Molecular Mechanisms of Pharmacological Action
Neurotransmitter Agents
Neurotransmitter Uptake Inhibitors
Peripheral Nervous System Agents
Pharmacologic Actions
Physiological Effects of Drugs
Respiratory System Agents
Sensory System Agents
Therapeutic Uses processed this record on November 25, 2014