Serotonin toxicity-serotonin syndrome

Serotonin toxicity is caused by excessive levels of serotonin (5-hydroxytryptamine, 5-HT) in the central and peripheral nervous systems. The syndrome can potentially be life-threatening and presents with a triad of autonomic instability, neuromuscular excitation and changes of mental status. The diagnosis can only be made based on the clinical picture. A differential diagnosis from syndromes partly exhibiting similar symptoms can be guided by established criteria, such as the Hunter criteria. Most crucial is the patient's current medication and drug history. Agents that have the potential to induce serotonin toxicity are monoamine oxidase inhibitors, selective serotonin or serotonin-noradrenalin reuptake inhibitors as well as illegal drugs and some new psychoactive substances. In most cases these agents are present in overdose or there is a synergism of two or more drugs. The diagnosis is complicated in mild forms and fatal cases. This article gives an overview on the pathophysiological mechanisms, the causes and treatment of serotonin toxicity.