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A Look at Natural Product Interactions

December 27, 2012
Josephine P. Briggs, M.D.
Josephine Briggs, M.D.

National Center for Complementary and Alternative Medicine

View Dr. Briggs's biographical sketch

This week, one of the most e-mailed articles on The New York Times Web site was its Well blog, which discussed how grapefruit is responsible for many drug reactions. We’re learning that the chemical constituents within grapefruit affect the bioavailability of many drugs, including some cholesterol, high blood pressure, and anti-cancer drugs—as well as some opiates, birth control pills, and many other medications. In some cases the grapefruit increases the metabolism of the drug, and in other cases it suppresses, meaning that the person taking the drugs is, in essence, under- or over-medicating. This can be a dangerous proposition.

So, too, do we see these types of interactions with natural products. At NCCAM, we’re investing in research to explore the issue of interactions of natural products with drugs and other products people ingest, including grapefruit. We are in the process of developing materials for clinicians and consumers regarding potential interactions so they can make informed decisions… So stay tuned, and we will keep you posted on our progress in this important area.


Grapefruit has known interactions with drugs.


Comments are now closed for this post.

I have heard about the interactions with grapefruit and certain drugs.  Have any studies been done on the effect of grapefruit with natural products and which ones? Thank you,    Patricia Moore 

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@Patricia Moore - Compounds in grapefruit inhibit CYP3A4 and thus, there hypothetically will be an interaction with any natural products that are also metabolized by CYP3A4.   

A research team at the University of Florida Citrus Research and Education Center has developed a new grapefruit variety that may lack these CYP3A inhibitors and will avoid these interactions.

Looking forward to a much needed nutriceutical-pharmaceutical database. Thank you for your efforts. 

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