A low dose of aripiprazole attenuates the subject-rated effects of d-amphetamine

Despite increased reports of amphetamine abuse and dependence, a putative pharmacotherapy has yet to be identified. In a previous study from our laboratory, 20 mg aripiprazole, an atypical antipsychotic that has partial agonist activity at D₂ receptors, attenuated many of the behavioral effects of d-amphetamine. Aripiprazole (20 mg) also impaired performance on a computerized version of the DSST when administered alone, indicating that the attenuation observed may have been functional as opposed to receptor mediated. The present experiment was conducted to determine whether a lower dose of aripiprazole (10 mg) could acutely attenuate the discriminative-stimulus, subject-rated, and physiological effects of d-amphetamine (2.5-15 mg) without impairing performance as measured with a computerized version of the DSST. The results of the present experiment indicate that 10 mg aripiprazole attenuated some abuse-related behavioral effects of d-amphetamine and was generally devoid of effects, including significant performance impairment, when administered alone. These findings suggest that 10 mg aripiprazole would be a reasonable starting dose for the treatment of stimulant abuse and dependence. Future research should examine the effects of chronic aripiprazole administration in combination with methamphetamine or cocaine.