Using herbal medications may put patients at risk during and after surgery, said researchers in the July 11 issue of The Journal of the American Medical Association.
University of Chicago researchers evaluated studies, case reports and reviews addressing the safety and pharmacology of eight commonly used herbal medications—echinacea, ephedra, garlic, ginkgo, ginseng, kava, St. John’s wort and valerian.
They found that complications can arise from these herbs’ direct, pharmacodynamic or pharmacokinetic effects. Direct effects include bleeding from the use of garlic, ginkgo and ginseng; cardiovascular instability from the use of ephedra; and hypoglycemia from the use of ginseng.
Researchers found pharmacodynamic herb-drug interactions with the use of kava and valerian. These herbs often are used as sleep aids and may increase the sedative effects of anesthetics. Pharmacokinetic herb-drug interactions with the use of St. John’s wort included increased metabolism of many drugs used in the perioperative period.
According to the study, the American Society of Anesthesiology suggests that patients stop using herbal medications two to three weeks before surgery. Researchers suggested a more targeted approach, as this amount of lead time may not be possible in all cases. They found that some herbal medications are eliminated quickly and may be discontinued closer to surgery: ephedra, at least 24 hours before surgery; garlic, seven days; ginkgo, 36 hours; ginseng, seven days; kava, 24 hours; and St. John’s wort, five days. They did not recommend when to discontinue echinacea or valerian use.
Because patients may not volunteer that they are taking herbal medications, researchers recommend that health care professionals specifically ask patients about their histories of using herbal medications as far ahead of surgery as possible.
