Cardiotoxicity in a citalopram and olanzapine overdose

This is a case of a citalopram and olanzapine overdose causing seizures and severe cardiotoxicity.

A 21-year-old man presented unresponsive, with seizures, to an Emergency Department. The patient's initial electrocardiogram demonstrated a widened QRS of 160 ms and a normal QT/QTc interval of 400/487 ms consistent with cardiac sodium channel blockade. Within 30 min of arrival, peak citalopram and olanzapine levels were measured to be 522 ng/mL and 505 ng/mL, respectively. Measured levels remained supratherapeutic until 13.6 h and 42.6 h after arrival for citalopram and olanzapine, respectively. The patient developed bradycardia and hypotension that required multimodal therapies including sodium bicarbonate boluses, vasopressors, and transvenous pacing. Seizures and cardiotoxicity continued while citalopram, but not olanzapine, was supratherapeutic.

This case describes cardiotoxicity directly correlated with supratherapeutic citalopram levels in overdose.