IJCCM October-December 2003 Vol 7 Issue 4 Indian J Crit Care Med July-September 2005 Vol 9 Issue 3 Case Report A fatal case of severe serotonin syndrome accompa- nied by moclobemide and paroxetine overdose Serkan Sener, 1 Levent Yamanel, 2 Bilgin Comert 2 Abstract Aim: To present a fatal case of serotonin syndrome accompanied by moclobemide and paroxetine over- dose. Case presentation: A 34-year-old married woman was presented following intentional ingestion of 3.5 g moclobemide and 2.6 g paroxetine. She was drowsy, agitated, and having rigor. In 1 h she developed myoclonus and diffuse muscle rigidity prominent in lower extremities. All laboratory tests were unremark- able except hyperglycemia (160 mg/dl), sinus tachycardia (103/min), and metabolic acidosis (7.051 pH, 52 mmHg pO2, 74.7 mmHg pCO2, 15% HCO3, 77% SaO2). Despite oxygen supplementation, her respiratory acidosis got worse and the SaO2 concentration decreased to 72%. Endotracheal intubation and paralysis were decided to control muscle hyperactivity followed by hyperthermia (max. 42.3ºC) unresponsive to benzodiazepine. Even aggressive supportive treatment (mechanical ventilation, buffer replacement, cy- proheptadine, and dantrolene) were applied, the patient could not recover and suffered cardiopulmonary arrest 20 h after presentation. Conclusion: Physicians working in the emergency departments and inten- sive care units, managing patients presenting with acute ingestion of selective serotonin reuptake inhibi- tors combined with monoamine oxidase inhibitors, should be aware of recognizing and treating serotonin stndrome. This is because many of these patients may require intensive care monitoring as well as tracheal intubation and ventilatory support. Key Words: Moclobemide, Paroxetine, Serotonin syndrome Introduction serotonin release (amphetamine and its derivatives, Serotonin syndrome is a rare but important drug-in- cocaine), (3) inhibition of serotonin uptake into presyn- duced complication of antidepressant therapy, which can aptic neuron (selective serotonin reuptake inhibitors be produced by any drug or, more commonly, by a com- [SSRIs], tricyclic antidepressants [TCAs], bination of drugs that increase central serotonin dextromethorphan, meperidine, tramadol, (4) inhibition neurotransmission. [1] Five basic mechanisms can in- of serotonin metabolism (moclobemide and selegiline), crease serotonin neurotransmission: (1) augmentation and (5) direct stimulation of postsynaptic receptors of serotonin production (l-tryptophan), (2) increase in (buspirone). Serotonin syndrome (SS) comprises vari- able alterations in cognition and behavior, autonomic From: 1 Acibadem Bursa Hospital, Department of Emergency Medicine, Bursa, Turkey 2 Gulhane Military Medical Academy, Department of Emergency Medicine, Ankara, Turkey Correspondence: Serkan Sener, Acibadem Bursa Hospital, Department of Emergency Medicine, Nilufer, Bursa, Turkey. E-mail: ssenermd@yahoo.com nervous system function, and neuromuscular activity. Although, fortunately, most patients with SS improve with supportive care alone or combined with specific drug therapy, in some most severe presentation, SS rapidly progresses to cardiac arrest, coma, seizures, or multi- ple organ failure. [2–5] Free full text available from www.ijccm.org 173