Escitalopram pharmacogenetics: CYP2C19 relationships with dosing and clinical outcomes in autism spectrum disorder

BACKGROUND AND AIMSelective serotonin reuptake inhibitors such as escitalopram are commonly used to treat patients with autism spectrum disorder (ASD), but there are individual differences in treatment response and tolerability. CYP2C19 encodes the primary enzyme responsible for escitalopram metabolism and we investigated whether polymorphisms in CYP2C19 were related to symptoms and dosing in a pharmacogenetic study of ASD. PARTICIPANTS AND METHODSParticipants completed the Aberrant Behavior Checklist – Community Version (ABC-CV) weekly for 6 weeks. Escitalopram was initiated at a dose of 2.5 mg per day, with weekly increases to 20 mg unless intolerable side-effects occurred. Three CYP2C19 metabolizer groups, including ultrarapid, extensive, and reduced metabolizers, were examined in relation to symptom improvement and tolerated dose. RESULTSABC-CV scores improved over the course of treatment (P