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Case report
Serotonin syndrome caused by drug to drug interaction between escitalopram and dextromethorphan
  1. Prudence Dy1,
  2. Victor Arcega1,
  3. Wael Ghali1,
  4. Winifred Wolfe2
  1. 1Department of Medicine, Monmouth Medical Center, Long Branch, New Jersey, USA
  2. 2College of Medicine, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
  1. Correspondence to Dr Victor Arcega, vaarcegamd{at}


A 63-year-old woman with a history of long-standing depression, maintained on escitalopram, presented with altered mental status. Patient had recently been prescribed dextromethorphan-promethazine cough syrup 2 weeks prior for an upper respiratory tract infection. On admission, she was lethargic and obtunded and found to have inducible myoclonus on examination. The rest of her physical exam was unremarkable. Pertinent lab and imaging findings showed QTc prolongation on ECG, negative electroencephalogram and CT head findings, essentially normal blood tests and a negative toxicology screen. The patient was admitted to the step down unit for close observation; both escitalopram and the cough syrup were suspended and was supportively managed. Overnight the patient's mental status improved and the serial EcGs showed resolution of the prolonged QTc. Patient was discharged home without further complication.

  • drugs and medicines
  • drug interactions
  • psychiatry(drugs and medicines)
  • general practice/family medicine

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  • Contributors The contributing authors VA and PD have no conflict of interests. We thank our faculty attending, WG, for guidance and feedback of this report; and thank WW for her valuable contributions to this report as well.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.