Post-Injection Delirium/Sedation Syndrome after Olanzapine Long-Acting Intramuscular Injection - Who is at Risk?

The post-injection olanzapine delirium/sedation syndrome (PDSS) was observed in a 60-year-old Caucasian, schizophrenic, non-smoker and underweight [body mass index (BMI), 18.2kg/m(2)] women after the fourth intramuscular injection of 405mg olanzapine pamoate. Clinical symptoms of PDSS were similar to those of acute oral olanzapine intoxication. The patient received supportive treatment and recovered fully. High olanzapine concentrations in serum, with maximum level of 698ng/mL, were confirmed by liquid chromatography with tandem mass spectrometry (LC-MS/MS). The authors wonder whether a low BMI and advanced age may predispose patients to PDSS occurrence.