International Journal of Clinical Pharmacy

, Volume 34, Issue 5, pp 686–688 | Cite as

A venlafaxine and mirtazapine-induced serotonin syndrome confirmed by de- and re-challenge

  • Liesbeth DecoutereEmail author
  • Sabrina De Winter
  • Liesbeth Vander Weyden
  • Isabel Spriet
  • Maarten Schrooten
  • Jos Tournoy
  • Katleen Fagard
Case Report


Case description A 85 year old woman with a history of severe depression treated with mirtazapine and venlafaxine was admitted to the hospital twice after progressive deterioration of her general condition evolving to unconsciousness. Clinicians diagnosed a metabolic encephalopathy caused by a urinary tract infection which was treated appropriately. Although mirtazapine was stopped during the first hospitalization, the patient’s general practitioner restarted mirtazapine four days before readmission. During rehospitalization, she developed extreme restlessness, hyperreflexia and an increased tone in the lower limbs. She was hypertensive and tachycardic. Excessive sweating, elevated creatine kinase levels and bilateral mydriasis were noticed. Urinary analysis showed positive levels of mirtazapine and venlafaxine and both drugs were withdrawn. Symptoms resolved within 48 h after discontinuation of her antidepressants. Conclusion To our knowledge, this is the first case of the serotonin syndrome confirmed by a positive challenge, de-challenge and re-challenge.


Advers drug reaction Mirtazapine Rechallenge Serotonin syndrome Venlafaxine 




Conflicts of interest

The authors declare no conflict of interest.


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Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Liesbeth Decoutere
    • 1
    Email author
  • Sabrina De Winter
    • 1
  • Liesbeth Vander Weyden
    • 2
  • Isabel Spriet
    • 1
  • Maarten Schrooten
    • 3
  • Jos Tournoy
    • 2
  • Katleen Fagard
    • 2
  1. 1.Pharmacy DepartmentUniversity Hospitals LeuvenLeuvenBelgium
  2. 2.Department of Gerontology and GeriatricsUniversity Hospitals LeuvenLeuvenBelgium
  3. 3.Department of SurgeryUniversity Hospitals LeuvenLeuvenBelgium

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