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to press release index Caution with Taking Chinese Medicines Before Anaesthesia and Surgery Needed
A review of the medical literature suggests that some herbal medicines may impair clotting, change blood electrolyte levels, cause cardiovascular side-effects or increase the potency of the anesthetic. Various TCHM are frequently used by the public, but there is little information about the risk of related adverse events if they have to undergo surgery. The Department of Anaesthesia and Intensive Care at The Chinese University of Hong Kong studied the incidence of TCHM use within two weeks of surgery, and examined the relationship between TCHM use and the risk of unexpected adverse events. This is the first study to examine the clinical outcomes of surgical patients taking TCHM and provides information for developing recommendations to reduce the risk of TCHM-related events. Data were collected from patients undergoing major surgery from January 2003 to September 2004. Information collected included recent TCHM use and unexpected adverse events occurring around the time of surgery. The study was funded by a grant from the Research Grants Council of the Hong Kong Special Administrative Region, China. Of the 601 patients surveyed, 483 (80%) patients took one or more self-medicated TCHM in the form of over-the-counter herbal soups (79%), herbal teas (37%) and pre-packed preparations (33%). 71 (12%) patients did not take any form of TCHM (non-users). 47 (8%) patients took TCHM by prescription, but 20 of them did not know any or all of the herbal ingredients. Eleven patients could provide a copy of the prescription listing individual herbs in the decoction. Compared with non-users and self-medicated TCHM users, patients taking TCHM prescription were 2 times more likely to have an adverse event before surgery after adjusting for patient characteristics. Adverse events probably caused by TCHM prescriptions included prolonged bleeding time (1 patient) and low potassium levels in the blood (3 patients). Some of these patients required additional investigations and a change in their anaesthetic care. The risk of complications during and after surgery and anaesthesia did not increase with TCHM use, but this may have been because the doctors asked specifically about the TCHM use and changed their management if necessary. The researchers conclude that the common practice of taking over-the-counter herbal teas, herbal soups and pre-packed preparations was not associated with adverse events. However, some herbs are known to cause problems, especially when large doses are taken. These include licorice (¥Ì¯ó), Rehmannia (¦a¶À), Astragalus (¶À¯Ï), Atractylodes (¥Õ¥º) and Eucommia (§ù¥ò). Using TCHM prescriptions before surgery and anaesthesia is potentially harmful because they are more likely to contain potent herbs at higher doses, and patients may not be able to tell doctors what the prescription contained. Based on the sample, it is estimated that each year 130 patients scheduled for surgery at the Prince of Wales Hospital are taking TCHM prescription and have a side effect that would increase the risk of anaesthesia and surgery if not detected. Researchers argue that ¡§Western¡¨ medicines may also be associated with complications but the nature and dose of these drugs are known and familiar to doctors. Hence, closer collaboration among practitioners of Western and Traditional Chinese Medicines will enhance awareness of the potential adverse effects and interactions of their treatment. Although it has been recommended that people should stop taking herbal medicines for up to two weeks before surgery, this may not be necessary for common over-the-counter TCHM. Yet, patients should tell their health professionals if they have taken any recent TCHM to minimize unforeseen complications. |