Did you know? St. John’s Wort, one of the most researched plants in modern herbal medicine, is known to interact with several classes of drugs. Due to its effect on cytochrome P450 isoenzymes CYP3A4, CYP2C9, CYP1A2, as well as P-glycoprotein, it can interact with warfarin, phenprocoumon, cyclosporin, HIV protease inhibitors, theophylline, digoxin, and oral contraceptives. It may also have a pharmacodynamic effect on serotonin and selective-serotonin reuptake inhibitors (SSRIs). (1)
The nutrients in food can also affect the metabolism of pharmaceutical drugs by increasing or decreasing the amount of drug the body absorbs. (2)
For example, when combined with certain pharmaceuticals, various nutrients or botanicals may:
- Increase the effects of a particular drug through inhibition of its metabolism
- Decrease the effects of a particular drug through potentiation of its metabolism
- Decrease the effects of a particular drug by decreasing absorption or increasing excretion
- Increase the effects of a particular drug by increasing absorption or decreasing excretion
- Cause additive or adverse effects
Understanding the interactions between pharmaceutical medications, nutrients, and botanical extracts can help to prevent possible negative health outcomes in patients and optimize the intended therapeutic effects of both.
The Fullscript Medical Advisory Team (FMAT) conducted a review of existing literature to develop a reference chart and guide summarizing common drug-nutrient interactions. The process involved a review of over 200 citations, including meta-analyses and systematic reviews, human randomized, double-blind, placebo-controlled (RDBPC) trials, in-vivo animal studies, and in-vitro studies. We will ensure that periodic review takes place to see that the content is up-to-date.The original content review included all literature posted/published via:
- Pubmed
- U.S. Food & Drug Administration
- American Academy of Family Physicians
- Journal of the American Medical Association
- Science Direct
Note: The information provided in this content is based on a review of the literature available at the time of publication. While the content is considered to be accurate at the time of publication, new or updated research released after the publication date may impact the accuracy of the information.
Please use your clinical discretion when using this resource. If you are not a practitioner, always consult with your practitioner first when considering how to address drug-nutrient interactions.
- Bushra, R., Aslam, N., & Khan, A. Y. (2011). Food-drug interactions. Oman Medical Journal, 26(2), 77–83.
- Henderson, L., Yue, Q. Y., Bergquist, C., Gerden, B., & Arlett, P. (2002). St John’s wort (Hypericum perforatum): drug interactions and clinical outcomes. British Journal of Clinical Pharmacology, 54(4), 349–356.
