Elsevier

General Hospital Psychiatry

Volume 30, Issue 3, May–June 2008, Pages 284-287
General Hospital Psychiatry

Case Reports
Serotonin syndrome: a complex but easily avoidable condition

https://doi.org/10.1016/j.genhosppsych.2007.09.007Get rights and content

Abstract

Serotonin syndrome is a potentially life-threatening adverse drug reaction caused by excessive serotonergic agonism in central and peripheral nervous system serotonergic receptors (Boyer EW, Shannon M. The serotonin syndrome. N Engl J Med 2005;352:1112–1120). Symptoms are characterized by a triad of neuron-excitatory features, which include (a) neuromuscular hyperactivity — tremor, clonus, myoclonus, hyperreflexia and, in advanced stages, pyramidal rigidity; (b) autonomic hyperactivitydiaphoresis, fever, tachycardia and tachypnea; (c) altered mental status — agitation, excitement and, in advanced stages, confusion (Gillman PK. Monoamine oxidase inhibitors, opioid analgesics and serotonin toxicity. Br J Anaesth 2005;95:434–441). It arises when pharmacological agents increase serotonin neurotransmission at postsynaptic 5-hydroxytryptamine 1A and 5-hydroxytryptamine 2A receptors through increased serotonin synthesis, decreased serotonin metabolism, increased serotonin release, inhibition of serotonin reuptake or direct agonism of the serotonin receptors (Houlihan D. Serotonin syndrome resulting from coadministration of tramodol, venlafaxine, and mirtazapine. Ann Pharmacother 2004;38:411–413). The etiology is often the result of therapeutic drug use, intentional overdosing of serotonergic agents or complex interactions between drugs that directly or indirectly modulate the serotonin system (Boyer EW, Shannon M. The serotonin syndrome. N Engl J Med 2005;352:1112–1120). Due to the increasing availability of agents with serotonergic activity, physicians need to more aware of serotonin syndrome. The following case highlights the complex nature in which serotonin syndrome can arise, as well as the proper recognition and treatment of a potentially life-threatening yet easily avoidable condition.

Section snippets

Case report

Ms. A, a 53-year-old Caucasian female with psychiatric history of depression, anxiety and intravenous opiate dependence, presented to the University of Massachusetts Medical Center emergency department with mental status changes. Her medications prior to admission included fluoxetine 40 mg daily, olanzapine 5 mg daily and methadone 50 mg daily. Bupropion 150 mg daily had recently been added due to persistent depressive symptomatology, but Ms. A stopped taking it 4 days prior to presenting to

Discussion

Serotonergic neurons are located in the midline raphe nuclei and play an integral part in the regulation of wakefulness, affective behavior, food behavior, thermoregulation and motor tone. In the periphery, serotonin assists in the regulation of vascular tone and gastrointestinal motility [1], [2]. Serotonin syndrome is not an idiopathic drug reaction but a predictable consequence of excess serotonergic agonism. Overstimulation of serotonin receptors results in a spectrum of clinical

Conclusion

The case described illustrates the complexities of serotonin syndrome and how it can be avoided through continued education of physicians, modifications of prescribing practices and pharmacological research. We believe that this case of serotonin syndrome was precipitated by the combination of venlafaxine, methadone and fluoxetine metabolite, as well as individual vulnerability. With more careful attention to Ms. A's psychopharmacological regime, Ms. A might have benefited from a simpler, less

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