Intravenous biperiden in akathisia: an open pilot study.

OBJECTIVE Antipsychotic-induced akathisia can be distressing and unendurable for prolonged periods. It has been shown that intramuscular biperiden is a relatively rapid and effective treatment for akathisia. However, the intravenous administration of biperiden may provide a more rapid effect, although this remains to be definitively proven. METHOD The subjects obtained for this study met the diagnostic criteria for schizophrenia as defined by the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). The therapeutic effect of i.v. and i.m. biperiden was studied in an open clinical trial in twenty-three (12 male and 11 female) patients who developed antipsychotic-induced acute akathisia as defined by the research criteria of the DSM-IV. Following the development of akathisia, 5 mg of biperiden was intravenously injected in seventeen patients and intramuscularly in six patients. The therapeutic effect of biperiden on akathisia was clinically assessed by using the rating scale of Barnes. RESULTS Following i.v. administration on biperiden, the mean time to onset and maximum effect occurred 1.6 (SD = 1.9) and 9.2 minutes (SD = 6.0), respectively. Furthermore, at the time of maximal effect, akathisia was completely ameliorated in all patients. The side effects reported were mild and transient. Following i.m. administration, the mean time to onset and maximum effect were 30.5 (SD = 5.9) and 50 minutes (SD = 7.4), respectively. Thus, the time to maximal effect was significantly less (40 minutes) after i.v. compared to i.m. administration. CONCLUSION These results suggest that i.v. administration of 5 mg of biperiden could be used to provide a rapid and effective treatment for patients with severe akathisia.