Published: March 2012


Complementary Corner: St John's Wort and Serotonin Syndrome

This article is more than five years old. Some content may no longer be current.

Prescriber Update 33(1): 4-5
March 2012

A single cup of Healtheries "Be Happy" tea and two days of citalopram treatment has been associated with a case of serotonin syndrome resulting in hospitalisation.

The report received by the Centre for Adverse Reactions Monitoring (CARM) describes a patient who was started on low dose citalopram one day after ingesting "Be Happy" tea. After just two doses of citalopram, the patient developed symptoms consistent with moderate serotonin syndrome1.

"Be Happy" tea lists 820 mg of St John's wort per tea bag.

St John's wort is a herbal substance from the plant St John'’s wort (Hypericum perforatum). St John’s wort is traditionally used for the treatment of depression and related conditions such as anxiety, tiredness, loss of appetite and trouble sleeping.

St John's wort is known to interact with selective serotonin reuptake inhibitors (SSRIs), in the same way as serotonergic drugs such as tramadol and citalopram, by further increasing the serotonin level in the brain2. The concomitant use of St John’s wort and SSRIs is not recommended and is included as an interaction in SSRI data sheets2.

Adverse reactions from interactions with other medicines could happen with any product that contains a large amount H. perforatum. Further information about clinically important interactions of St John's wort can be found in the February 2001 edition of Prescriber Update3.

Healthcare professionals are encouraged to ask patients about their use of complementary and alternative medicines and to report all suspected adverse reactions to CARM.

  1. Medsafe. 2010. Serotonin syndrome/toxicity - reminder. Prescriber Update, 31(4): 30-31
  2. European Medicines Agency. 2009. Community herbal monograph on Hypericum perforatum L., herba (well-established medicinal use). Doc. Ref. EMA/HMPC/101304/2008. URL:
  3. Medsafe. 2001. Interactions with St John’s wort (Hypericum perforatum) preparations. Prescriber Update, 20: 42-48


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