Concomitant Use of Anticholinergic Agents with Atypical Antipsychotics in Schizophrenic Patients: A Preliminary Report

Woo, Young Sup; Chae, Jeong Ho; Jun, Tae Youn; Bahk, Won Myong

Abstract

OBJECTIVE
It is well known that antipsychotic drugs induce extrapyramidal symptoms such as dystonia, akathisia and parkinsonian symptoms even early in the treatment. With the advent of atypical antipsychotic drugs, the incidence of extrapyramidal symptoms has decreased, but danger still exists. Hence, anticholinergic agents are often indicated in treatment of schizophrenia with antipsychotics.
METHODS
In this observational retrospective study, we examined the use of anticholinergic agents among schizophrenic patients who were initiated on risperidone, olanzapine, or quetiapine, the three most widely prescribed atypical antipsychotics. We reviewed medical records of schizophrenic patients who were initiated on risperidone, olanzapine or quetiapine from January 2004 through December 2004 and continuously treated with the antipsychotics for 6 months. The data were analysed using one way ANOVA, Mann-Whitney U test, chi-square test or Fisher's exact tests.
RESULTS
The study yields two major findings. Firstly, compared with risperidone initiators, there were significantly fewer olanzapine initiators who used anticholinergic agent concomitantly. Secondly, there were significantly fewer olanzapine or quetiapine initiators than risperidone initiators who prescribed anticholinergic agent on the same day when antipsychotics was initiated.
CONCLUSION
As the use of anticholinergic agent is a proxy for the presence of extrapyramidal symptom, these findings suggest that risperidone may be more associated with extrapyramidal symptoms than olanzapine or quetiapine. Controlled studies comparing them to one another should be of particular interest.