Intravenous benztropine and propranolol challenges in acute neuroleptic-induced akathisia.

We challenged six patients suffering from acute neuroleptic-induced akathisia (NIA) with intravenous benztropine (2 mg), propranolol (1 mg), and placebo (saline) using a random, double-blind cross-over design to examine the effects of the drugs on the subjective, objective, and global manifestations of NIA. Benztropine produced a significant amelioration of NIA, more apparent in its subjective component. Propranolol failed to produce a significant improvement overall in any of the akathisia measures, with only one patient showing clinical improvement. The patients demonstrated considerable placebo effect and marked variation in their responses to the drugs.