Evaluation of antipsychotic and concomitant medication use patterns in patients with schizophrenia.

OBJECTIVE: To describe antipsychotic medication use patterns in an inner-city, outpatient population of indigent patients with schizophrenia.
METHODS: This retrospective cohort study used the Regenstrief Medical Record System to identify schizophrenic patients receiving antipsychotic medication(s). Patients were included and identified as initiating a new treatment episode if they did not receive any antipsychotic prescription for 90 days before their first antipsychotic prescription in 1995. Each patient was followed for 1 year.
RESULTS: Three hundred and sixteen patients met study criteria. Typical and atypical (clozapine and risperidone) antipsychotic agents were selected as initial therapy in 88% and 12% patients, respectively. The majority of patients (71.5%) were exposed to only one antipsychotic agent during their treatment year. Approximately 25% of all patients switched from one antipsychotic to a different antipsychotic during 12 months of therapy. Nearly 90% of patients augmented their prescribed antipsychotic with a concomitant medication during the 12-month study period. Approximately 30% of the cohort received treatment with an antipsychotic for 12 continuous months and were, thus, classified as having stable antipsychotic therapy. The majority of patients (67.1%) had periods of interrupted therapy (range, 1-11 months) during the 12 month study period.
CONCLUSION: As of 1995 an overwhelming majority of schizophrenic patients in this indigent, inner-city population initiated therapy with a typical antipsychotic. Patients frequently switched antipsychotics and discontinued their therapy during the 1 year study period. Reasons for switching or discontinuing may include the following: ineffective therapy; patient intolerance; change in symptoms; and improved assessment and understanding of the diagnosis or physician preference.