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With Comments from John La Puma, MD, FACP
October 2001; Volume 4; 119
Source: Ang-Lee MK, et al. Herbal medicines and perioperative care. JAMA 2001; 286:208-216.
Widespread use of herbal medications among the presurgical population may have a negative impact on perioperative patient care. The literature on commonly used herbal medications was reviewed in the context of the perioperative period to attempt to provide rational strategies for managing their preoperative use.
The MEDLINE and Cochrane Collaboration databases were searched for articles published between January 1966 and December 2000 using the search terms "herbal medicine," "phytotherapy," and "alternative medicine" and the names of the 16 most commonly used herbal medications. Additional data sources were obtained from manual searches of recent journal articles and textbooks.
Studies, case reports, and reviews were selected that address the safety and pharmacology of eight commonly used herbal medications for which safety information pertinent to the perioperative period was available. Safety, pharmacodynamic, and pharmacokinetic information was extracted from the selected literature and any discrepancies were resolved.
Echinacea, ephedra, garlic, ginkgo, ginseng, kava, St. John’s wort, and valerian are commonly used herbal medications that may pose a concern during the perioperative period. Complications can arise from these herbs’ direct and pharmacodynamic or pharmacokinetic effects. Direct effects include bleeding from garlic, ginkgo, and ginseng; cardiovascular instability from ephedra; and hypoglycemia from ginseng. Pharmacodynamic herb-drug interactions include potentiation of the sedative effect of anesthetics by kava and valerian. Pharmacokinetic herb-drug interactions include increased metabolism of many drugs used in the perioperative period by St. John’s wort.
During the preoperative evaluation, physicians should explicitly elicit and document a history of herbal medication use. Physicians should be familiar with the potential perioperative effects of the commonly used herbal medications to prevent, recognize, and treat potentially serious problems associated with their use and discontinuation.
This article received a lot of media attention. Is it, as Dr. Andrew Weil says, "...more herbal alarmism from conventional physicians"? Or is it, as the Tufts University Health and Nutrition Letter claims, "Herbs and Surgery: A Risky Combination"?
Because operative patients appear to use supplements more often than the general population, and because nearly three-quarters of patients have been shown to omit their supplements from pre-op histories and evaluations, there’s more than a little reason to be concerned. These University of Chicago investigators found no randomized, controlled trials about herbs and the perioperative period. So they reviewed everything else they could find, including textbooks and case reports—not the only literature available, but among the best available in the medical literature (the authors didn’t appear to investigate other literatures, which is part of Dr. Weil’s complaint). Here are their (excerpted) take-home points:
1. Patients who may require perioperative immunosuppression, such as those awaiting organ transplantation, should be counseled to avoid taking echinacea.
2. Ephedra’s sympathomimetic effects have been associated with more than 1,070 reported adverse events, including fatal cardiac and central nervous system complications. Ephedra’s elimination half-life is 5.2 hours.
3. Garlic inhibits platelet aggregation in a dose-dependent fashion; patients should discontinue use of garlic at least seven days prior to surgery, especially if postoperative bleeding is a particular concern or other platelet inhibitors are given.
4. Ginkgo appears to inhibit platelet-activating factor; the elimination half-lives of the terpenoids (active compounds) after oral administration are between three and 10 hours. Patients should discontinue taking ginkgo at least 36 hours prior to surgery.
5. Platelet inhibition caused by ginseng may be irreversible; it is probably prudent to recommend that patients discontinue ginseng use at least seven days prior to surgery. Actions are attributed to the ginsenosides that belong to a group of compounds known as steroidal saponins.
6. Kavalactones have dose-dependent effects on the central nervous system; peak plasma levels occur 1.8 hours after an oral dose, and the elimination half-life of kavalactones is nine hours. Kava may potentiate the sedative effects of anesthetics; patients taking kava should discontinue use at least 24 hours prior to surgery.
7. St John’s wort exerts its effects by inhibiting serotonin, norepinephrine, and dopamine reuptake by neurons and by inducing the cytochrome isoform P4503A4. Hypericin and hyperforin, thought to be the active ingredients, have median elimination half-lives of 43.1 and 9.0 hours, respectively. Patients should discontinue use at least five days prior to surgery.
8. Valerian produces dose-dependent sedation and hypnosis, and carries the risk of benzodiazepine-like withdrawal. A several-week, pre-op taper is advised, or benzodiazepines can be used to treat withdrawal symptoms should they develop during the postoperative period.
Although it’s true that prescription medication likely has much more effect than herbs on most intra- and perioperative adverse effects (with the possible exception of St. John’s wort), an alarm ought to be sounded about these herbs. Herbs are medications. Treat them as such—especially in your patients who may be surgical candidates.