Antipsychotic Polypharmacy Trends Among Medi-Cal Beneficiaries With Schizophrenia in San Diego County, 1999–2004

OBJECTIVE: This study examined trends and costs of second-generation antipsychotic polypharmacy among Medicaid beneficiaries with schizophrenia in San Diego County. METHODS: Medicaid data were used to identify 15, 962 persons with schizophrenia receiving antipsychotic medications between 1999 and 2004. The yearly proportion of beneficiaries receiving second-generation antipsychotic polypharmacy, duration of polypharmacy, inpatient admissions, and pharmaceutical costs were examined. RESULTS: The proportion of clients receiving second-generation antipsychotic polypharmacy increased from 3. 3% in 1999 to 13. 7% in 2004, whereas annual antipsychotic medication costs increased from 4, 128 to 5, 231 (2004 dollars). Among those receiving second-generation polypharmacy, the percentage receiving second-generation polypharmacy for 12 months increased from 5. 1% to 14. 4%, and the percentage hospitalized increased from 7. 2% to 9. 0%. CONCLUSIONS: The prevalence of long-term second-generation antipsychotic polypharmacy and its associated costs increased substantially between 1999 and 2004. Prescribing antipsychotic polypharmacy is an unproven and costly strategy that if left unchanged could lead to administrative efforts to cut costs and dictate practice.