The rate, pattern, and cost of use of antiparkinsonian agents among patients treated for schizophrenia in a managed care setting.

Objective: To examine the use and economic cost of antiparkinsonian agents during the medication management of patients diagnosed with schizophrenic disorders in a naturalistic healthcare setting.

Design: Cross-sectional retrospective analysis of 1-year (1999) administrative data from a large managed care organization.

Patients And Methods: Patients were 1938 adults who were treated for a schizophrenic disorder. Monthly per patient utilization rate and cost of antiparkinsonian agents, and the proportion of the total psychiatric medication costs attributed to the antiparkinsonian agents, were compared across antipsychotic medications (typical, atypical, olanzapine, risperidone), age, sex, and diagnostic subtype.

Results: About one third (39%) of the patients were treated with typical antipsychotics only, and half of them (51%) received antiparkinsonian agents. Those treated with atypical antipsychotics only (41%) were considerably less likely to receive antiparkinsonian agents (25%), and the rate of use differed by atypical type such that risperidone-treated patients were more likely to receive antiparkinsonian agents than those treated with olanzapine. Lower utilization rates of antiparkinsonian agents were also found among patients age 75 years or older, and among those diagnosed with a schizoaffective disorder. Average monthly per patient cost of antiparkinsonian agents was 3.0 dollars, constituting 2.6% of the monthly expenditure on all psychiatric medications.

Conclusions: Adjunctive use of antiparkinsonian agents differs widely among patients who are treated with typical or atypical antipsychotic drugs, and differs between types of atypical antipsychotics. The choice of atypical antipsychotics that have a lower liability for extrapyramidal symptoms may assist in optimizing the long-term functional outcomes of schizophrenia patients.