Herbal medicines and anaesthesia

Abstract

The use of herbal remedies has been around for centuries and their use in both western and eastern societies are increasing. Patient surveys have reported that 12% of Americans, 12% of Australians, and 4.8% of patients in the UK use herbal remedies. The World Health Organization (WHO) estimates that up to 80% of the world’s population still depend on herbal medicines. Although there has been concern in the medical community about the potential complications arising as a result of patient use of herbal medicines, the exact degree of concern remains unclear as very few of the huge number of remedies have been formally researched. The assumption by patients and healthcare professionals that these products are ‘natural’ and therefore safe is clearly dangerous. Many patients do not disclose their use and hence the anaesthetist may remain oblivious to potential side-effects and drug interactions. As pharmacokinetic and pharmacodynamic data are lacking, the American Society of Anaesthesiologists recommends that patients discontinue the use of herbal medications 2–3 weeks before surgery. However, patients are often unaware of this recommendation and, furthermore, may present for emergency surgery. There are no formal recommendations or guidelines governing their use for the perioperative period in the UK. Hence, all anaesthetists need to familiarize themselves with the potential perioperative complications that may occur. The aim of this article was to discuss the more commonly used herbal medicines, their side-effects and their effects on the conduct of anaesthesia. These include echinacea, ephedra, garlic, ginger, gingko biloba, ginseng, herbal diuretics, kava, St John’s Wort, and valerian.