Serotonin Syndrome

Serotonin syndrome is a rapidly evolving toxidrome caused by excessive serotonergic activity, usually after serotonergic medicines are combined or a single agent is taken in overdose. The bedside pattern is excess central nervous system activity, autonomic activation, and neuromuscular overactivity. Clonus and hyperreflexia are especially useful clues because they point toward serotonin toxicity rather than an undifferentiated fever or agitation. The immediate clinical sequence is to stop further serotonergic exposure, provide supportive care, reduce muscle activity and heat production, and identify complications early.