ANALYSIS OF POTENTIAL DRUG INTERACTING PAIRS ASSOCIATED WITH ANTIPSYCHOTICS AMONG MEDICAID PATIENTS WITH SCHIZOPHRENIA OR BIPOLAR DISORDER

bipolar disorder often receive multiple medications as part of their treatment regimens. Since many antipsychotics are metabolized by cytochrome P450 (CYP450) isoenzymes (1A2, 2D6, and 3A4), we proposed to assess the risk of receiving potential drug-drug interaction (DDI) pairs associated with the inhibition or induction of CYP450 isoenzymes. Methods: Using the Ohio fee-for-service Medicaid claims database from 1/1/2001 to 12/31/2003, a total of 44,511 patients (18≤age≤65) with a schizophrenia, schizoaffective disorder, or bipolar disorder diagnosis and receiving at least one study antipsychotic were selected for this study. Study antipsychotics included chlorpromazine, haloperidol, perphenazine, aripiprazole, clozapine, olanzapine, risperidone, quetiapine, and ziprasidone. Any clinically significant (moderate or severe) DDI pair was defined to have concomitant exposure if 1) an antipsychotic and an interacting medication wer