Beneficial effect of low-dose mirtazapine in acute aripiprazole-induced akathisia.

Low-dose mirtazapine was found to be efficacious for neuroleptic-induced akathisia. We evaluated whether mirtazapine is also effective for akathisia induced by the partial dopamine D2 receptor agonist aripiprazole. Medical charts were retrospectively analyzed for eight patients who developed akathisia while being treated with aripiprazole. All scored at least 2 (mild akathisia) on the Barnes Akathisia Rating Scale (BARS) and were treated with mirtazapine (15 mg/day) for a mean of 8.5 days. There was a statistically significant reduction in the BARS subjective, distress, and global (P<0.01 to P<0.001), but not objective (P=0.21) subscales. Five (62.5%) patients fulfilled the criteria of response, a decrease of at least two points on the BARS global subscale. Low-dose mirtazapine was well tolerated, and mild sedation, the only side effect (three patients), was transient. A large-scale controlled investigation is warranted to substantiate clinical utility of mirtazapine for akathisia induced by aripiprazole and other second-generation antipsychotics.