Atypical antipsychotic metabolism and excretion.

BACKGROUND: The metabolic/biotransformation pathways of atypical antipsychotics (aripiprazole, clozapine, iloperidone, olanzapine, paliperidone, quetiapine, risperidone, and ziprasidone) have been characterized and reviewed. However, comparisons of excretory pathways remain unexplored. OBJECTIVE: To analyze the excretion profile of atypical antipsychotic agents and compare the overall magnitude of metabolism (changed vs. unchanged drug) and route of excretion (feces vs. urine). Secondary objectives include providing: 1) dosing information in hepatic and renal impairment, and 2) context of the specific enzymes and pathways involved in each agents' biotransformation. METHODS: Published literature and each manufacturer's radiolabeled drug absorption, distribution, metabolism and excretion data and U.S. prescribing information were reviewed. RESULTS: With the exception of paliperidone, atypical antipsychotics undergo extensive metabolism (i.e.,