New Delhi. Herbal medications are frequently used by patients undergoing surgery. Some of these agents have physiologic effects that could be deleterious in the preoperative period, including precipitation of clotting disorders and interactions with anesthetics.

Most patients may not disclose their during the preoperative assessment, said Dr K K Aggarwal, president, Heart Care Foundation of India. Since there is no evidence that herbal medications improve surgical outcomes, and there are theoretic reasons that these agents may increase preoperative morbidity, they must be stopped before surgery.

1. Ephedra (ma huang) may increase the risk of heart attack and stroke and should be discontinued at least 24 hours prior to surgery.

2. Garlic may increase bleeding risk and should be discontinued at least 7 days prior to surgery.

3.Ginkgo may increase bleeding risk and should be discontinued at least 36 hours prior to surgery.

4. Ginseng lowers blood sugar and may increase bleeding risk and should be discontinued at least seven days prior to surgery.

5. Kava may increase the sedative effect of anesthetics and should be discontinued at least 24 hours prior to surgery. The Food and Drug Administration (FDA) has issued a safety alert about an association between kava use and fatal hepatotoxicity.

6. St. John’s wort may diminish the effects of several drugs by induction of cytochrome p450 enzymes and should be discontinued at least five days prior to surgery.

7. Valerian may increase the sedative effect of anesthetics and is associated with benzodiazepine–like withdrawal. There are no data on preoperative discontinuation. Ideally it is tapered weeks before surgery; if not, withdrawal is treated with benzodiazepines.

8. Echinacea is associated with allergic reactions and immune suppression. There are no data on preoperative discontinuation.

Take home message: Herbal drugs should be stopped at least one week before surgery.