SEROTONIN SYNDROME

Selective serotonin reuptake inhibitors (SSRIs) are replacing tricycli c antidepressants (TCAs) with increasing frequency in the United State s. Although SSRI poisoning lends to be less serious than TCA poisoning , the incidence of adverse side effects and drug interactions may be g reater. The serotonin syndrome is a potentially severe adverse drug in teraction characterized by the triad of altered mental status, autonom ic dysfunction, and neuromuscular abnormalities. The serotonin syndrom e is similar to the neuroleptic malignant syndrome, leading to misdiag nosis. Although serotonin syndrome may result in death, most patients recover completely with supportive care alone. The main pathophysiolog ic mechanism appears to be excessive 5-hydroxytryptophan stimulation; this finding is supported by reports of beneficial effects with seroto nin-antagonist treatment. The incidence of the serotonin syndrome may increase as SSRIs continue to replace TCAs. Morbidity and costly diagn ostic procedures may be avoided if prompt diagnosis and appropriate tr eatment are provided.