The purpose of this study is to investigate whether aripiprazole will decrease cocaine self-administration, subjective effects and cravings compared to placebo.
Despite the recent increase in data about cocaine's basic neurochemical mechanisms of action, progress towards the development of an effective pharmacological treatment for cocaine abuse has been disappointing. We are proposing to use our laboratory model of repeated dose cocaine self-administration to assess the potential efficacy of the novel antipsychotic, aripiprazole. Aripiprazole is a partial agonist at both the dopamine D2 receptor and at the serotonin 5HT1a receptor, while antagonizing the 5HT2a receptor. By functioning as a partial D2 agonist, aripiprazole is hypothesized to function as a D2 antagonist during hypodopaminergic states, such as during cocaine use, while functioning as a D2 agonist during hypodopaminergic states, such as during cocaine withdrawal. This 42-day, outpatient/inpatient/outpatient/inpatient protocol will evaluate the effects of aripiprazole maintenance (0, 15 mg/day) on cocaine craving, subjective effects, and self-administration using a within-subjects design. Non-treatment seeking cocaine abusers will be maintained outpatient for 16 days of dose maintenance prior to inpatient cocaine self-administration sessions. 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 choose between repeated doses of smoked cocaine and $5. In addition to measuring their cocaine self-administration, we will measure the cardiovascular and subjective effects of cocaine under each aripiprazole maintenance condition.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
26
Participants received aripiprazole (15mg/day) in conjunction with a dose-response of cocaine (0, 12, 25, 50 mg).
Placebo (0 mg/day) in conjunction with a dose-response of cocaine (0, 12, 25, 50 mg).
Irving Center for Clinical Research
New York, New York, United States
Cocaine Self-administration
Mean number of cocaine choices as a function of cocaine dose and aripiprazole dose (n=8). Participants sampled the dose of cocaine available for the session and then had five choices to respond for money ($5.00) or cocaine using a modified progressive-ratio schedule.
Time frame: 5 days
Subjective Effects of Cocaine
Mean Visual Analog Scale (VAS) ratings (items: "Quality", "Pay for Dose", "Good Drug Effect", and "Cocaine Craving") from 0-100mm as a function of cocaine dose and aripiprazole dose 4 min following a single administration of cocaine (the "sample dose") at the start of the session. For "Quality" item, the perceived quality of the drug is rated. The higher the rating, the better quality the drug was perceived to be. For "Pay for Dose" item, the likelihood that the participant would pay for the drug is indicated. Higher ratings indicate a better likelihood that the person would pay for the dose received. For "Good Drug Effect", the likelihood of feeling a good drug effect is indicated. The higher the number, the more of a good drug effect the person reported. For "Cocaine Craving", the intensity of craving is reported. Higher scores indicate more craving for cocaine.
Time frame: 5 days
Plasma Cocaine
Mean plasma cocaine levels after a single administration of each cocaine dose as a function of aripiprazole and cocaine dose.
Time frame: 8 minutes
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