1. Although seen as beneficial and safe, herbal medications and supplements are not completely risk free.
2. Use of herbal medications is largely unregulated and herbal medicines may vary in composition and amount of herbs in their mixtures and may be contaminated with other herbs and non-herbal medicines.
3. Herbal medications have a number of interactions and side effects which are relevant to surgery and anaesthesia.
4. Knowledge and documentation of the use of herbal medicines is important to anticipate, prevent and manage problems that may arise from herbal medications taken during the perioperative period.
5. While recommendations for discontinuation of individual herbal medications vary from 36 hours to 9 days, a more general approach is that in elective surgery, herbal medications should be discontinued 2 weeks prior to surgery.
Perioperative management of cardiovascular, anticoagulation (including bridging therapy), diabetes, steroids and psychotropic medication is detailed elsewhere in the related chapters. In this chapter we will consider herbal medications with relevance to the forthcoming surgery and anaesthesia.
Herbal medicines are used frequently in the United Kingdom and are perceived to have a good safety profile (Skinner & Rangasami, 2002). Survey of patients undergoing elective surgery found use of herbal medicines in 57 per cent of patients. The most common were echinacea (48 per cent), aloe vera (30 per cent), ginseng (28 per cent), garlic (27 per cent) and ginkgo biloba (22 per cent) (Adusumilli et al., 2004). For a variety of reasons, patients do not volunteer information about intake of herbs and a large number of anaesthetic departments have no appropriate practices in place to acquire and record history on use of herbal medicines (Hogg & Foo, 2010).
Although seen as beneficial and safe, herbal medicines are not completely risk free. Examples of related complications include myocardial infarction from food supplements containing ephedra alkaloids, bilateral subdural haematomas associated with ginkgo, epidural haematoma due to excessive garlic ingestion and acute renal failure in patients who had been taking Chinese herbal slimming pills. There is also evidence of organ rejection secondary to reduced bioavailability of immunosuppressants with concomitant St John’s wort administration and immunosuppression and post-operative infections with long-term echinacea use (Hogg & Foo, 2010).
Use of herbal medicines is largely unregulated as they are marketed as food supplements or cosmetics and exempted from the product licensing under the Medicines Act 1968. Herbal medicines may vary in composition and amount of herbs in their mixtures and may be contaminated with other herbs and non-herbal medicines. This variation limits reliability of research on action and side effects of herbal medicines.
Herbal medicines may affect perioperative patients by their effects on patients’ physiology, side effects and interaction with other drugs given perioperatively. Table 21.1 gives an account of commonly used herbal medicines, and summarises their significance with regards to surgery and perioperative recommendations.
Legend: NSAID= Non-steroidal anti-inflammatory drug