新規抗精神病薬の臨床導入に伴う処方内容の変化：大学病院精神科外来における検討

Abstract

Many studies have reported that the polypharmacy of conventional antipsychotics at high doses is still common in the majority of Japanese patients with schizophrenia. However, most of them targeted prescriptions for inpatients in psychiatric hospitals and very few have been done on prescriptions for outpatients at university hospitals. We conducted our prescription survey in the psychiatric outpatient unit of Kyoto University in June 2001, after risperidone was introduced, and June 2004, when quetiapine, perospirone, and olanzapine were also available. From it, we collected data on use of antipsychotics and concomitant medications. The numbers of patients with schizophrenia in 2001 and 2004 were 262 and 203, respectively. The proportion of patients receiving novel-antipsychotic medications and novel-antipsychotic monotherapy increased from 30.9% to 70.0% and from 17.2% to 35.0%, respectively, in the two periods. Thus, most patients receiving novelantipsychotic medications were also given conventional antipsychotics. Further, though the percentage of patients prescribed antiparkisonian medicines decreased from 83.6% to 69.0%, biperiden-equivalent dosages did not change significantly. This resulted from the fact that high-dose antiparkisonian medicines were administered to patients receiving polypharmacy of conventional and novel antipsychotics and indicates that the benefit of administering novel psychotics for extrapyramidal symptoms was not realized because they were co-administered with conventional antipsychotics. Further studies are needed to examine the factors inhibiting the change to novel-antipsychotic monotherapy in schizophrenia.