Treatment of Antipsychotic-Induced Akathisia: Role of Serotonin 5-HT_2a Receptor Antagonists

Akathisia is one of the most prevalent and distressing adverse effects associated with antipsychotic drug treatment. Propranolol, a non-selective beta-adrenergic receptor antagonist, is currently considered a first-line treatment for antipsychotic-induced akathisia (AIA). Surprisingly, the evidence for its anti-akathisia effect is modest. Propranolol's side effects (e.g. orthostatic hypotension, bradycardia), contraindications (e.g. asthma) and increased complexity in titration schedules limit its use in some patients. Anticholinergic agents and benzodiazepines merely provide symptomatic relief in patients with AIA. Effective and well-tolerated treatment remains a major unmet need in akathisia and warrants a search for new anti-akathisia agents. Accumulating evidence during the last two decades indicates that agents with marked postsynaptic serotonin 5-HT_2a receptor antagonism (ritanserin, cyproheptadine, trazodone, mianserin, mirtazapine) may represent a new class of potential anti-akathisia remedies. Among these agents, low-dose mirtazapine (7.5 mg or 15 mg once daily) has demonstrated the most compelling evidence for therapeutic efficacy. In this narrative review we highlight the clinical significance of AIA, outline major approaches for its management and propose a practical algorithm for its treatment.