Serotonin syndrome: fentanyl and selective serotonin reuptake inhibitor interactions.

Serotonin syndrome is a rare but potentially fatal adverse drug reaction associated with increased serotonergic activity in the central nervous system. It is characterized by a triad of symptoms, which include altered mental status, neuromuscular hyperactivity, and autonomic instability or hyperactivity. Due to the potential of rapid onset, it is important for clinicians to recognize the signs and symptoms of serotonin syndrome. Serotonin syndrome symptoms may resemble other conditions. Although this article focuses on serotonin syndrome as a result of an adverse interaction of selective serotonin reuptake inhibitors (SSRI) and fentanyl, it is important for not only anesthesia professionals, but all clinicians--such as those in emergency medicine and critical care--to be aware of this syndrome and its management. This article discusses the clinical manifestations of the serotonin syndrome and highlights reported cases of serotonin syndrome specifically related to an interaction between SSRIs and fentanyl, a commonly used opioid in anesthesia practice.