Risperidone and Cytochrome P450 3A

Letter to the Editor

Sir: We read with great interest the recent article by Ereshefsky on pharmacokinetics and drug interactions of the new antipsychotics. This work is timely and provides invaluable information for clinicians regarding drug interactions with atypical antipsychotics. In his discussion of cytochrome P450 3A (CYP3A) isoenzyme induction by carbamazepine, Ereshefsky relates that metabolism of certain typical and atypical antipsychotics usually increases when carbamazepine is coadministered.