Synergistic interactions between mirtazapine and prazosin prevent the induction and expression of behavioral sensitization to cocaine in rats

Cocaine abuse and dependence are a global public health problem. To date, no effective therapy has been established to treat cocaine dependence but mirtazapine-as well as prazosin used in preclinical and clinical trials-has been shown to decrease cocaine behavioral effects. Therefore, our hypothesis was that the effectiveness of mirtazapine might improve when used in combination with prazosin. This study investigated the combined effect of mirtazapine and prazosin on cocaine-induced locomotor activity impairment in rats subjected to locomotor sensitization testing. We found that chronic treatment with the mirtazapine-prazosin combination significantly improved the effect of single mirtazapine dosing on cocaine-induced locomotor activity and on the induction and expression of cocaine sensitization. These results suggest that the combined use of mirtazapine and prazosin may be a potentially effective treatment to attenuate induction and expression of locomotor sensitization to cocaine.