The widespread use of herbal and dietary supplements poses ongoing challenges in perioperative medicine. Surveys suggest that up to half of surgical patients use these products, yet fewer than 40% disclose this information to their healthcare providers. This puts patients at risk for avoidable complications under anesthesia. Though marketed as “natural,” these supplements can influence drug metabolism, coagulation, and cardiovascular stability. Since the U.S. Food and Drug Administration (FDA) does not strictly regulate their production, the composition and potency of these supplements can vary substantially between products. Consequently, preoperative identification of supplement use and appropriate management before and after anesthesia are critical to minimizing perioperative risk.
Herbal products can interact with anesthetic agents via multiple pharmacologic mechanisms. Some, such as St. John’s wort, induce cytochrome P450 pathways, which leads to increased clearance and decreased plasma levels of anesthetic drugs and opioids. Others, such as kava and valerian, exhibit gamma-aminobutyric acid (GABA)-agonist activity, which can augment sedative effects and prolong emergence from anesthesia. The Society for Perioperative Assessment and Quality Improvement (SPAQI) advises discontinuing most herbal agents approximately two weeks before surgery to account for their pharmacokinetic variability and potential interaction with anesthesia and anticoagulant therapy (1).
The most clinically significant risks stem from supplements that affect hemostasis. Garlic, ginkgo biloba, ginseng, and vitamin E inhibit platelet aggregation and increase the risk of bleeding. These supplements may also potentiate the effects of anticoagulants, such as warfarin and heparin. Additionally, supplements such as ephedra (ma huang) and bitter orange may cause cardiovascular instability, including hypertension and tachyarrhythmias, during induction and maintenance of anesthesia. This necessitates complete discontinuation well before surgery (2).
Certain supplements may also alter glucose metabolism. Ginseng, aloe vera, and fenugreek can exacerbate hypoglycemia, while licorice root may cause sodium retention and hypokalemia. In diabetic patients, these metabolic effects necessitate careful glucose monitoring during the perioperative period if supplement cessation is incomplete. The SPAQI guidelines recommend stopping the use of hypoglycemia-prone supplements two weeks before surgery and anesthesia.
The preoperative evaluation should explicitly inquire about supplement and over-the-counter product use. Direct questioning by anesthesiologists significantly improves disclosure (3). Patients should be encouraged to bring all supplement containers to their preoperative appointment to ensure an accurate assessment and documentation. Supplements with prolonged elimination or known hemostatic effects should not be resumed until the risk of postoperative bleeding has resolved. The American Society of Anesthesiologists (ASA) advises that resumption should occur only when oral intake normalizes and surgical healing is stable.
Interestingly, not all supplements are contraindicated. Some supplements, such as melatonin, chamomile, and passionflower, have been shown to reduce preoperative anxiety and improve sleep without interfering with anesthetic metabolism or recovery. In controlled settings, melatonin has demonstrated efficacy comparable to midazolam for anxiolysis, and it can be safely administered during the perioperative period. However, all supplement use should be reviewed by the care team to ensure safety and optimize patient outcomes. The team should evaluate whether to pause use before anesthesia and surgery, when to do so, and when use can be safely resumed after the procedure.
In summary, the lack of FDA regulation and the variable pharmacologic activity of herbal and dietary supplements create perioperative risk. The safest approach remains proactive disclosure and discontinuation of high-risk supplements at least two weeks before elective surgery and resuming their use only once recovery from anesthesia and surgery is stable. Perioperative teams should stay informed about the latest literature and educate patients about supplement use. By integrating standardized screening and evidence-based cessation practices, anesthesiologists can significantly reduce the incidence of preventable adverse events related to supplement–anesthesia interactions.
References
1. Cummings KC 3rd, Keshock M, Ganesh R, et al. Preoperative Management of Surgical Patients Using Dietary Supplements: Society for Perioperative Assessment and Quality Improvement (SPAQI) Consensus Statement. Mayo Clin Proc. 2021;96(5):1342-1355. doi:10.1016/j.mayocp.2020.08.016
2. Hatfield J, Saad S, Housewright C. Dietary supplements and bleeding. Proc (Bayl Univ Med Cent). 2022;35(6):802-807. Published 2022 Sep 15. doi:10.1080/08998280.2022.2121575
3. Ben-Arye E, Attias S, Levy I, Goldstein L, Schiff E. Mind the gap: Disclosure of dietary supplement use to hospital and family physicians. Patient Educ Couns. 2017;100(1):98-103. doi:10.1016/j.pec.2016.07.037
4. Ang-Lee MK, Moss J, Yuan CS. Herbal medicines and perioperative care. JAMA. 2001;286(2):208-216. doi:10.1001/jama.286.2.208