Etomidate and St John's Wort: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
St John's Wort
No brand names on recordEtomidate
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
An increased risk of cardiovascular collapse and/or delayed emergence from anesthesia
Interaction Deep Dive
St. John's Wort use prior to surgery using anesthesia has been associated with complications such as hypotension during anesthesia in one case and delayed emergence from anesthesia in another case32. Definite causality has not been determined, but the two patients were 21 and 23 years of age, had no known medical conditions, and were not on any regular medicines besides St. John's Wort. To avoid complications, it is recommended to discontinue St. John's Wort at least 5 days prior to the use of anesthesia 3.
Why it happens (mechanism)
Unknown
Literature reports
3 reports — tap to read
a) In a systematic review of studies of pharmacokinetic interactions involving St John's Wort, concomitant use with ketamine in 1 study (N=12) resulted in a decrease in ketamine AUC of 58% with a St John's wort dosage of 300 mg 3 times daily (containing hyperforin dosage of 7.5 mg/day) 1.
b) A healthy 23-year-old female experienced hypotension during general anesthesia for hysteroscopy. She had been taking St. John's Wort for the prior 6 months and no other medications. She had no known drug allergies. General anesthesia was induced with fentanyl, propofol, tubocurarine, and succinylcholine, and maintained with isoflurane, nitrous oxide, and oxygen. The patient became hypotensive (blood pressure 60/20 mmHg) shortly after induction, and received fluid boluses, ephedrine, and phenylephrine which raised her blood pressure to 70/40 mmHg. An additional bolus of epinephrine raised her blood pressure to 110/80 mmHg. The hypotensive episode lasted approximately 10 minutes with no additional symptoms. A previous surgery 2 years prior to this one using the same anesthetics was uneventful. The authors acknowledged that the anesthetics may have caused the hypotension, it is also possible that St. John's Wort may alter the adrenergic system, reducing its ability to respond to the stress of anesthesia 2.
c) A 21-year-old female experienced delayed emergence from general anesthesia using fentanyl, propofol, sevoflurane, oxygen, and nitrous oxide. The patient was taking St. John's Wort 1000 milligrams (mg) three times daily with a product standardized to 0.3% hypericin for the previous 3 months for depression, and no other medications. Total anesthesia time was approximately 10 minutes. The patient emerged from the anesthesia after 90 minutes. Lab tests for blood glucose, blood count, electrolytes, arterial blood gases, and toxicology screen were within normal limits. The event was considered associated with St. John's Wort and the authors hypothesized that St. John's Wort may have caused the profound sedation through interaction with the anesthetic agents centrally, at neurotransmitter receptor sites, and at hepatocellular enzyme sites (particularly cytochrome P450 3A4). The authors recommend that St. John's Wort be discontinued at least 5 days prior to surgery 3.
Common questions
Can I take Etomidate and St John's Wort together?
An increased risk of cardiovascular collapse and/or delayed emergence from anesthesia Always confirm with your pharmacist or prescriber before making any change.
How serious is the Etomidate and St John's Wort interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Etomidate or St John's Wort need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (3)
- Chrubasik-Hausmann S, Vlachojannis J, & McLachlan AJ: Understanding drug interactions with St John's wort (Hypericum perforatum L.): impact of hyperforin content. J Pharm Pharmacol 2019; 71(1):129-138.
- Irefin S & Sprung J: A possible cause of cardiovascular collapse during anesthesia: Long-term use of St. John's Wort. J CLin Anesth 2000; 12:498-499. PubMed
- Crowe S & McKeating K: Delayed emergence and St. John's Wort. Anesthesiology 2002; 96(4):1025-1027. DOI
Keep reading about St John's Wort
Keep reading about Etomidate
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