Aripiprazole and dehydroaripiprazole

Aripiprazole is an atypical antipsychotic with a novel structure. It is used at a dose of 10-15 mg once daily, up to a maximum of 30 mg/d. Aripiprazole undergoes extensive hepatic metabolism via CYP2D6 and CYP3A4 including dehydrogenation, hydroxylation, and N-dealkylation. Dehydroaripiprazole has pharmacological activity, and accumulates in plasma to ca. 40 % of the aripiprazole concentration at steady-state, which is achieved in about 14 days. The plasma half-life averages 75 h (aripiprazole) and 94 h (dehydroaripiprazole). Aripiprazole and dehydroaripiprazole assay is useful in assessing adherence and may help in dose optimisation, and if acute poisoning is suspected. A reference range of 150–300 µg/L of aripiprazole (60-120 µg/L dehydroaripiprazole) has been suggested (12 h post-dose sample).