Olanzapine-Induced Withdrawal Oculogyric Crisis in an Adolescent With a Neurodevelopmental Disorder.

This case report describes an adolescent female with a complex psychiatric history and Fragile X syndrome who developed an antipsychotic-withdrawal emergent oculogyric crisis (OGC) in approximately 12 hours following reduction in olanzapine dose from 20 mg total daily dose to 5 mg twice daily. The team concluded that the OGC was likely related to olanzapine withdrawal based on the following clinical factors: 1) prior treatment with olanzapine 20 mg for 4 to 5 days/week for several months, without such reaction; 2) proximity of the OGC to the olanzapine dose reduction (within 12 hours); and 3) lack of recurrence with olanzapine dose increase. Additionally, her neurodevelopmental disorder and age were identified as risk factors for an acute dystonic reaction. Published case reports describe withdrawal emergent dystonia, including OGC, following abrupt discontinuation of clozapine in adults. Given structural similarities of clozapine and olanzapine it can be postulated that this phenomenon is based in muscarinic receptor function-specifically, super-sensitized muscarinic receptors may react to excessive acetylcholine upon antipsychotic discontinuation, resulting in muscle motor end plate hyperactivity. Providers caring for pediatric patients with neurodevelopmental disorders should carefully consider risks for withdrawal emergent dystonia, obtain clear medication histories, and consider slow, conservative tapers when discontinuing antipsychotics.