[Post-injection syndrome after depot injection of olanzapine]

Olanzapine pamoate injection is an anti-psychotic depot to be administered intramuscularly once every 2-4 weeks. A post-injection syndrome may occur shortly after administration, resulting in an acute intoxication with olanzapine.

A 42-year-old patient with a schizophrenic disorder lost consciousness 30 min after administration of olanzapine pamoate. He was admitted to a nearby hospital with tachycardia, hypotension, pin-point pupils and respiratory distress leading to reduced oxygen saturation. He was ventilated during one night and recovered within 2 days.

A post-injection syndrome may develop after administration of olanzapine pamoate when the entire dose olanzapine is released at once from the muscle. Therefore, the patient should be observed for at least 3 hours after every injection. The risk of a post-injection syndrome and the necessary observation period should to be taken into account when deciding to start treatment with olanzapine pamoate depot.