Cases That Test Your Skills

An insidious onset of symptoms

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Because serotonergic agents are used frequently and readily by primary care clinicians as well as psychiatrists, the ability to properly diagnose this syndrome is vital, particularly because severe cases can rapidly deteriorate.1,9,16,17 This presentation of a single serotonergic agent causing significant symptoms that worsened over months is not typical, but important to recognize as a patient begins to experience autonomic instability. As was the case with Ms. S, it is important to remain vigilant when changing dosages or adding medications. Symptoms of serotonin syndrome might be vague and difficult to diagnose, especially if the clinician is not aware of the variability of presentation of this syndrome. Cyproheptadine can be used safely and rapidly and should be considered a treatment option for serotonin syndrome.

OUTCOME Hypertension resolves

After her first dose of cyproheptadine, Ms. S’s blood pressure drops to 146/86 mm Hg. Three hours later, she repeats the cyproheptadine dose and her blood pressure drops to 106/60 mm Hg. She reports that her anxiety has lessened, although she is still tremulous. Overall, she says she feels better. She experiences improvement of her condition with a pharmacologic regimen of bupropion, gabapentin, and hydroxyzine.

Several weeks later, her health returns to baseline, with complete resolution of hypertension.

Bottom Line

Although serotonin syndrome is most commonly associated with co-administered serotonergic medications, symptoms can emerge with a single, moderately dosed agent. Treatment includes withdrawing the offending agent, and administering a serotonin antagonist. Mild cases of serotonin syndrome usually resolve.

Related Resources

  • Turner AH, Kim JJ, McCarron RM. Differentiating serotonin syndrome and neuroleptic malignant syndrome. Current Psychiatry. 2019;18(2):30-36.
  • Iqbal MM, Basil MJ, Kaplan J, et al. Overview of serotonin syndrome. Ann Clin Psychiatry. 2012;24(4):310-318.

Drug Brand Names

Bupropion • Wellbutrin, Zyban
Cyproheptadine • Periactin
Dextromethorphan • Benylin
Duloxetine • Cymbalta
Fluoxetine • Prozac
Gabapentin • Neurontin
Hydroxyzine • Atarax
Linezolid • Zyvox
Tramadol • Ultram, Ryzolt

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