Prescription patterns for patients with schizophrenia in Korea: a focus on antipsychotic polypharmacy.

Objective: This study investigated the prescription patterns for Korean patients with schizophrenia with a particular focus on antipsychotic polypharmacy. All data were gathered from patients presenting at 41 tertiary university hospitals and 8 secondary hospitals. Methods: Data from three multicenter studies conducted in Korea were retrospectively reviewed and integrated to identify patients with schizophrenia who had their antipsychotic medication switched to paliperidone extended-release between 2008 and 2009. The rates for antipsychotic polypharmacy, combined use of different antipsychotic classes with a special focus on atypical antipsychotics, and psychotropic polypharmacy using benzodiazepines, mood stabilizers, and other relevant drugs were identified. Results: Of the 851 Korean patients analyzed in this study, 20.4% (n=173) had been prescribed antipsychotic polypharmacy. Of the 678 patients receiving antipsychotic monotherapy, 6.9% (n=47) were prescribed a typical antipsychotic and 93.1% (n=631) were prescribed an atypical antipsychotic. Of the 173 patients receiving a combination of antipsychotic drugs, only 6.4% (n=11) had been prescribed polypharmacy with typical antipsychotics, while 46.82% (n=81) were prescribed atypical+atypical antipsychotics or typical+atypical antipsychotics. The highest co-prescription rates for other psychotropic drugs in conjunction with antipsychotics included benzodiazepines (30.3%), anticholinergic drugs (28.8%), antidepressants (13.3%), beta-blockers (10.1%), and mood stabilizers (8.7%). Conclusion: The present findings demonstrate that the rate of antipsychotic polypharmacy is relatively low in Korea and that Korean clinicians prefer to prescribe atypical, rather than typical, antipsychotic drugs. This suggests that there is a distinct prescription pattern in Korea that is focused on antipsychotic polypharmacy.