What is the dermatologic preoperative evaluation and management of St. John's wort?

Updated: Feb 23, 2021
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: Dirk M Elston, MD  more...
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A number of clinical trials have reported efficacy in the short-term treatment of mild-to-moderate depression. The most recent multicenter clinical trial concluded that St. John's wort is not effective in treating major depression. Nonetheless, St. John’s wort is widely used by many patients. The compounds believed to be responsible for pharmacologic activity are hypericin and hyperforin. Commercial preparations are often standardized to a fixed hypericin content of 0.3%.

St. John's wort exerts its effects by inhibiting serotonin, norepinephrine, and dopamine reuptake by neurons. Concomitant use of this herb with or without serotonin reuptake inhibitors may create a syndrome of central serotonin excess. Contradictory studies report that St. John's wort is comparable in effectiveness to most antidepressant agents. In 13 studies comparing the herbal remedy with placebo, 55.1% of St. John's wort–treated depressed patients showed significant improvement, versus 22.3% with placebo. The use of St. John's wort can significantly increase the metabolism of many concomitantly administered drugs, some of which are vital to the perioperative care of certain patients.

Single-dose and steady-state pharmacokinetics of hypericin, pseudohypericin, and hyperforin have been determined. After oral administration, peak plasma levels of hypericin and hyperforin were obtained at 6 hours and at 3.5 hours, and their median elimination half-lives were 43.1 hours and 9 hours, respectively. The long half-life and alterations in the metabolism of many drugs make concomitant use of St. John's wort particularly risky in the perioperative setting. The pharmacokinetic data suggest that patients taking this herbal medication should discontinue wort use at least 5 days prior to surgery. This discontinuation is especially important for patients waiting for organ transplantation or for those who may require oral anticoagulation postoperatively. St. John's wort also affects digoxin pharmacokinetics, possibly by inducing the P-glycoprotein transporter. Patients should be counseled to avoid taking St. John's wort postoperatively.

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