Drug Interaction Report

GENERALLY AVOID: An isolated case report suggests that St. John's wort may prolong the sedative effects of some drugs used in general anesthesia. The case patient was a 21-year-old woman who received general anesthesia with fentanyl 1 mcg/kg and propofol 3 mg/kg IV, and sevoflurane in oxygen and nitrous oxide via a facemask. Total anesthesia time was approximately 10 minutes. Thirty minutes after anesthesia, the patient could not be aroused, even when subjected to painful stimulation. She was not easily rousable until 90 minutes postanesthesia. A subsequent interview revealed nothing unusual except for use of St. John's wort for the past three months. At the time of the procedure, the patient was taking St. John's wort 1000 mg (500 mg tablets standardized to 0.3% hypericin) three times a day. The authors suggested that St. John's wort may have caused profound sedation by interacting with anesthetic agents centrally, at neurotransmitter (GABA) receptor sites, and at hepatocellular enzyme sites.

MANAGEMENT: Based on the suspected interaction, it may be appropriate to advise patients to discontinue use of St. John's wort 5 days before surgery.

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

GENERALLY AVOID: An isolated case report suggests that foods containing large amounts of tyramine may precipitate a hypertensive crisis in patients treated with St. John's wort. The mechanism of interaction is unknown, as St. John's wort is not thought to possess monoamine oxidase (MAO) inhibiting activity at concentrations achieved in vivo. The case patient was a 41-year-old man who had been taking St. John's wort for seven days prior to presentation at the emergency room with confusion and disorientation. The patient recalled last eating aged cheese and having a glass of red wine approximately 10 hours prior to admission. No other cause of delirium or hypertension could be identified. In addition, alcohol may potentiate some of the pharmacologic effects of St. John's wort. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

MANAGEMENT: Until further information is available, patients treated with St. John's wort should consider avoiding consumption of protein foods in which aging or breakdown of protein is used to increase flavor. These foods include cheese (particularly strong, aged or processed cheeses), sour cream, wine (particularly red wine), champagne, beer, pickled herring, anchovies, caviar, shrimp paste, liver (particularly chicken liver), dry sausage, figs, raisins, bananas, avocados, chocolate, soy sauce, bean curd, yogurt, papaya products, meat tenderizers, fava beans, protein extracts, and dietary supplements. Caffeine may also precipitate hypertensive crisis so its intake should be minimized as well. Patients should also be advised to avoid or limit consumption of alcohol.