Managing Herbal Medicines in Patients Undergoing Surgery

Just as the U.K. believes health care to be a fundamental right and makes that right a reality, that country’s National Health Service (NHS) also regularly provides excellent health information — more so than U.S. agencies — for patients, physicians, pharmacists and other health professionals.

A recent article on the NHS website (http://www.nelm.nhs.uk) points out that although more and more patients are using herbal medicines — usually without a doctor’s instruction — they often do not disclose such use to medical personnel, partly due to the misapprehension that because herbal medicines are natural, they are safe. However, as in the U.S., these products do not have to be proven either safe or effective to be allowed on the market, and the content and safety are thus unpredictable. Furthermore, many patients may not be informed about known adverse effects, alone or in combination with prescribed drugs.

To address these concerns, U.K. pharmacists prepared a well-researched and informative series for health care professionals and the general public. The authors’ intention was to “summarise information from the current literature regarding commonly used herbal medicines and how to manage their use during the peri-operative period… [including] recommendations on discontinuation of herbal medicines prior to elective surgery.” The authors focused on the nine such medicines that are in the widest use and for which information has been published regarding the risks of use around the time of surgery. They emphasized, as a key message, that “full disclosure of herbal medicines by patients and specific pre-operative questioning by medical staff [are] essential.”

The nine most common herbal medicines are discussed below, reprinted with permission* from NHS. It should be emphasized that the stated uses for the nine medicines (the “is used for…” information) are the ones for which the products are most often advertised and used, despite the absence of evidence from well-controlled studies that they are effective.

• Echinacea is used for the prophylaxis and treatment of viral, bacterial and fungal infections. It should be avoided before transplant surgery because it may decrease the effectiveness of immunosuppressants. Echinacea should be discontinued as far in advance as possible for any surgery, ideally 2 weeks prior to surgery.


• Ephedra, also known as ma huang, is used to promote weight loss, increase energy and treat respiratory conditions such as asthma and bronchitis. Adverse effects of ephedra include increased blood pressure and it may also affect cardiovascular function leading to cardiomyopathy. It should be discontinued at least 24 hours and ideally 2 weeks prior to surgery.


• Garlic has the potential to modify the risk of developing atherosclerosis by reducing blood pressure and thrombus formation and lowering serum cholesterol levels. Because it has been shown to decrease platelet aggregation it should be stopped 7 days prior to surgery especially if post-operative bleeding is a concern. Ideally, garlic should be discontinued 2 weeks prior to surgery.


• Ginger is used for motion sickness and vertigo as well as post-operative nausea and vomiting, it is also used as an anti-inflammatory. Ginger can cause hypoglycaemia, cardiac problems and it may increase the risk of bleeding due to its effect on platelet function. It should be stopped 2 weeks prior to surgery.


• Ginkgo is used to prevent the effects of aging, to increase energy, improve stress and improve appetite. It is also used for tinnitus, vertigo, memory enhancement and sexual dysfunction. It may affect platelet aggregation and should be stopped at least 36 hours prior to surgery because of the bleeding risk. Ideally, ginkgo should be stopped 2 weeks before surgery.


• Ginseng is used for a wide range of conditions including stress, memory loss, bleeding disorders, appetite loss and cancer. Ginseng may cause hypoglycaemia in fasting patients and may also cause platelet inhibition. It should be stopped at least 7 days prior to surgery and ideally 2 weeks before surgery.


• Kava is used as an anxiolytic and sedative. It can potentiate the sedative effects of anaesthetics and should be stopped at least 24 hours prior to surgery and ideally 2 weeks before surgery.


• St John’s Wort is widely used as an antidepressant. It significantly affects the metabolism of many other drugs because it induces cytochrome P450 enzymes. The effects of many conventional medicines including warfarin, alfentanil, midazolam and lidocaine could all be reduced by St John’s Wort. It should be discontinued 5 to 7 days prior to surgery especially if transplant surgery or if the patient needs warfarin post surgery. Ideally, St John’s Wort should be stopped 2 weeks prior to surgery.


• Valerian is used for insomnia. Because it causes hypnosis, the dose should be tapered several weeks prior to surgery. Valerian should not be stopped abruptly as it poses a risk of withdrawal syndrome.

What You Can Do

Although the recommendations for discontinuation timing vary, the authors of the study advise generally that patients stop using all herbal medicines two weeks before elective surgical procedures.

Scientists have not adequately studied the safety of herbal medicines in patients undergoing surgery. Just because a particular herbal medicine does not appear in the list does not indicate that that medicine is safe to use prior to surgery.

Patients should always inform their doctors of any herbal medicines they are using.

*UK Medicines Information (UKMi) pharmacists. Medicines Q&A: How should herbal medicines be managed in patients undergoing surgery? National Electronic Library for Medicines. www.nelm.nhs.uk. Accessed Dec. 5, 2012.