Evaluation of subjective effects of aripiprazole and methamphetamine in methamphetamine-dependent volunteers

A variety of neuropharmacological strategies are being pursued in the search for an effective treatment for methamphetamine (Meth) addiction. In this study, we investigated the safety and potential efficacy of aripiprazole, an antipsychotic agent acting on both dopamine and serotonin systems. We conducted a double-blind in-patient clinical pharmacology study to assess potential interactions between intravenous (i.v.) Meth (15 mg and 30 mg) and oral aripiprazole (15 mg). In addition, the effects of aripiprazole treatment on abstinence-related craving and cue-induced craving were evaluated. Participants included non-treatment-seeking, Meth-dependent patients (n=16), aged 18-45 yr, currently using Meth. Following baseline Meth dosing (15 mg and 30 mg), participants received 2 wk treatment with aripiprazole (n=8) or placebo (n=8). Participants then completed cue exposure sessions using neutral and Meth-related cues. Meth dosing (15 mg and 30 mg) was then repeated. Aripiprazole treatment had no effect on cue-induced Meth craving, or on daily baseline craving assessed over the course of medication treatment, although aripiprazole treatment was associated with increased craving independent of Meth dosing. Aripiprazole treatment was associated with significantly higher ratings on Addiction Research Center Inventory (ARCI) subscales reflecting euphoria and amphetamine-like effects following Meth dosing. Aripiprazole treatment was also associated with significant reductions in ratings of 'bad effects' and reductions on the ARCI subscale for sedation effects following Meth dosing. Aripiprazole treatment reduced the increase in systolic blood pressure following Meth dosing, but had no other effects on cardiovascular responses to Meth. Aripiprazole treatment did not alter the pharmacokinetics of Meth. These findings indicate that aripiprazole treatment appears to be safe in volunteers with Meth dependence, although the finding that aripiprazole increased some of the rewarding and stimulatory effects produced by acute Meth suggests that 15 mg aripiprazole is unlikely to be efficacious for the treatment of Meth dependence. Further research with lower doses of aripiprazole, possibly using study designs aimed at evaluating efficacy for relapse prevention, are needed before ruling out aripiprazole as a treatment for Meth dependence.