Effects of Vigabatrin on Cocaine Self-Administration
Study Details
Study Description
Brief Summary
The objective of this study is to determine if vigabatrin will decrease cocaine self-administration, cardiovascular effects, subjective effects and craving compared to placebo.
Condition or Disease | Intervention/Treatment | Phase |
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Phase 2 |
Detailed Description
Two recent open label clinical trials have reported that the anticonvulsant, gamma vinyl-GABA (GVG; vigabatrin), decreases relapse to cocaine use (Brodie et al., 2003, 2005). Vigabatrin increases neural GABA levels by irreversibly inhibiting the primary GABA degradation enzyme, GABA-transaminase; the hypothesized mechanism by which vigabatrin decreases cocaine relapse is by increasing GABA levels, thereby decreasing the effects of cocaine and cocaine-associated environmental cues on extracellular dopamine concentrations in the mesolimbic dopaminergic pathway (Morgan and Dewey, 1998). We are proposing to use our model of repeated dose cocaine self-administration to assess the interaction between vigabatrin and smoked cocaine under controlled laboratory conditions. This 57-day outpatient/inpatient /outpatient/inpatient protocol will evaluate the effects of vigabatrin maintenance (0, 3 g/day) on cocaine craving, subjective effects, and self-administration using a within-subjects design. Non-treatment seeking cocaine-dependent volunteers will be maintained outpatient for 14 days of vigabatrin maintenance prior to beginning each inpatient study phase. During the inpatient phases, volunteers will live on a hospital clinical research unit and will participate in laboratory sessions in which they will have the opportunity to purchase doses of smoked cocaine (0, 12, 25, 50 mg; $5/administration). In addition to measuring cocaine self-administration, we will measure the cardiovascular and subjective effects of repeated cocaine administration and cocaine craving under each vigabatrin maintenance condition. Determining vigabatrin's effects on a range of smoked cocaine doses will provide essential data on the mechanism of the vigabatrin-cocaine interaction.
Study Design
Arms and Interventions
Arm | Intervention/Treatment |
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Experimental: Vigabatrin, cocaine
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Drug: Vigabatrin
Drug: Cocaine
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Placebo Comparator: placebo, cocaine
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Drug: Vigabatrin
Drug: Cocaine
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Outcome Measures
Primary Outcome Measures
- Subjective effects []
- Cardiovascular effects []
- Cravings []
- Cocaine Administration []
Eligibility Criteria
Criteria
Inclusion Criteria:
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Meets DSM-IV criteria for current cocaine abuse
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Average use of smoked cocaine is at least 2x/week for past 6 mos; currently spends at least $70 per week on cocaine
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Has patterns of smoked cocaine use in terms of frequency and amounts which parallel or exceed those administered in the study
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Age 21-45
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Able to give informed consent, and comply with study procedures
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Agrees to practice an effective form of contraception
Exclusion Criteria:
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Current seizure disorder or heart disease
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Currently meeting DSM-IV criteria for all major psychiatric/psychotic disorders. Volunteers with a history of depression or psychosis will also be excluded (p. 43, Investigator's brochure)
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Dependence on substances other than cocaine or nicotine
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Request for drug treatment
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Judged to be noncompliant with study protocol
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Clinical laboratory tests outside normal limits that are unacceptable to the study physician (e.g., BP > 140/90; BUN, creatinine, LFTs > 1.5 ULN; hematocrit < 34 for women, < 36 for men; pseudocholinesterase deficiency)
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Current parole or probation
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Recent history of significant violent or suicidal behavior
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Pregnancy or lactation
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Baseline visual field defects
Contacts and Locations
Locations
Site | City | State | Country | Postal Code | |
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1 | Irving Center for Clinical Research | New York | New York | United States | 10032 |
Sponsors and Collaborators
- New York State Psychiatric Institute
- Novel Cocaine Pharmacotherapies
Investigators
- Principal Investigator: Margaret Haney, Ph.D., New York State Psychiatric Institute
Study Documents (Full-Text)
None provided.More Information
Publications
None provided.- 5096
- DA 10755