University of Chicago
Type of paper: Thesis/Dissertation Chapter
St. Johns Wort and its Anesthetic Implications
St. John’s Wort or hypericum perforatum is a herb which has gained importance in the treatment of certain psychological conditions like depression, anxiety, sleep-related disorders (Kaye, Kucera and Sabar et al, 2004), vitiligo (Sabar, Kaye and Frost, 2001), fibrositis, cancer, obsessive-compulsive neurosis, headache and sciatica (Kaye, Baluch and Kaye, 2007). It is also used in bronchitis, burns, gastritis, enuresis, hemorrhoids, insect bites, hypothyroidism, scabies, kidney disease and wound healing (Emst, 2002).
It is popularly known as amber, hardhay, goat weed, tipton weed or klamath weed (Kaye, Kucera and Sabar et al, 2004). The main active compounds of this herb are hypericin, pseudohypericin, rutin, quercitin and hyperin which probably act by GABA inhibition (Kaye et al, 2005). Some researchers have also suggested serotonin receptor inhibition and monoamino oxidase inhibition (Sabar et al, 2001). The herb can interact with other drugs and hence prior to administration of anesthesia, intake of St. John’s Wort must be questioned.
Photosensitization drugs like tetracycline and piroxicam, beta-sympathomimetic amines like pseudoephidrine, selective serotonin reuptake inhibitors and monoamine oxidase inhibitors should not be taken concomitantly with the herb (Kaye et al, 2005). This is because these drugs can exaggerate the side effects the herb produces. Some of the important side effects of St. John’s herb are dizziness, dry mouth, constipation, fatigue and nausea.
Concomitant use with serotonin-reuptake inhibitors can cause serotonergic syndrome which manifests as hypertonicity, myoclonus, hallucinosis, autonomic dysfunction, hyperthermia and death (Sabar et al, 2001). St. John’s Wort activates P450 system and thus induces hepatic enzyme resulting in increased elimination of certain drugs like oral contraceptives, anticoagulants and anti-viral drugs (Emst, 2002). One of the concerns associated with the use of this herb is during surgery.
Various studies have indicated that 7- 39% of patients undergoing surgeries have history of herbal medicine intake (Barbara, 2007). Herbal use has been associated with prolonged bleeding, hypertension and drug-herb interactions. Research has shown that 11% of surgery patients on herbs suffer from significant complications after surgeries which are either related to adverse effects of the herb or drug-herb interactions (Barbara, 2007).
Recent research has indicated that concomitant use of St. John’s herb with anesthetic drugs can cause cardiovascular collapse and also delayed emergence from anesthesia (Kaye et al, 2007). Since many patients do not consider herb as medicine and do not mention its intake during evaluation, every physician must attempt to elicit history of herb-intake during pre-anesthetic evaluation to prevent complications. St. Jonh’s Wort must be discontinued atleast 2 weeks prior to surgery (Barbara, 2007).