Prolonged serotonin toxicity with proserotonergic drugs in the intensive care unit

Serotonin toxicity secondary to drug therapy, interaction or overdose is an increasing phenomenon worldwide. A proportion of patients require admission to an intensive care unit, but the treatment needed is usually supportive and of short duration. Prolonged ICU admission to control ongoing or long-lasting serotonin toxicity has not been reported previously. We describe three patients with prolonged serotonin toxicity, lasting 12-18 days. Symptoms of toxicity were easily demonstrable in each and were refractory to currently recommended therapies. We review the pharmacological mechanisms that led to prolonged serotonin toxicity in these patients. Predictors for prolonged serotonin toxicity include involvement of irreversible monoamine oxidase inhibitors (MAOIs) or slow-release preparations resistant to the effects of activated charcoal (eg, lithium). We also discuss the implications of prolonged toxicity for critical care management, to maintain optimal patient outcomes.