Role of Mirtazapine in the Treatment of Antipsychotic-Induced Akathisia

OBJECTIVE: To evaluate the role of mirtazapine in the treatment of antipsychotic-induced akathisia. DATA SOURCES: MEDLINE (1966-February 2008) and PsycINFO (1967-February 2008) were searched using the terms akathisia and mirtazapine. A bibliographic search was conducted as well. STUDY SELECTION AND DATA EXTRACTION: All English-language articles identified from the search were evaluated. All primary literature was included in the review. DATA SYNTHESIS: Antipsychotic-induced akathisia can be difficult to manage and may respond to mirtazapine based on its antagonist activity at the serotonin 5-HT(2A)/5-HT(2C) receptors. Three case reports (N = 9 pts.), 1 placebo-controlled trial (N = 26), and 1 placebo- and propranolol-controlled study (N = 90) that evaluated mirtazapine for antipsychotic-induced akathisia have been published. Mirtazapine demonstrated a response rate of 53.8% compared with a 7.7% response rate for placebo, based on at least a 2-point reduction on the Barnes Akathisia Scale (global subscale; p = 0.004). Using the same criterion, mirtazapine and propranolol demonstrated efficacy based on response rates of 43.3% and 30.0% compared with placebo (6.7%; p = 0.0051). Mirtazapine was better tolerated than propranolol. In both studies, drowsiness was the most common adverse event associated with mirtazapine. CONCLUSIONS: Mirtazapine may be considered a treatment option for antipsychotic-induced akathisia. It may be especially useful for patients with contraindications or intolerability to beta-blockers and for those with comorbid depression or negative symptoms. Additional studies should be conducted to provide further evidence of mirtazapine's effectiveness in treating akathisia.