Olanzapine poisoning in patients treated at the National Poison Control Centre in Belgrade, Serbia in 2017 and 2018: a brief review of serum concentrations and clinical symptoms

Olanzapine is a thienobenzodiazepine class antipsychotic that strongly antagonises the 5-HT2A serotonin receptor, but acute poisonings are reported rarely. Symptoms of an overdose include disorder of consciousness, hypersalivation, myosis, and coma. Serum concentration higher than 0.1 mg/L is toxic, while concentration above 1 mg/L can be fatal. Here we report key data about 61 patients admitted to the National Poison Control Centre in Belgrade, Serbia over olanzapine poisoning in 2017 and 2018. The ingested doses ranged from 35 to 1680 mg, and time from ingestion to determination from two to 24 hours. In 34 patients olanzapine serum concentrations were in the therapeutic range and in 27 in the toxic range. In five patients they were higher than fatal, but only one patient died. The most common symptoms of poisoning were depressed consciousness (fluctuating from somnolence to coma), tachycardia, hypersalivation, hypotension, myosis, and high creatine kinase. All patients but one recovered fully after nonspecific detoxification and symptomatic and supportive therapy.