Herbal remedies are a multibillion-dollar industry. Sales of natural product supplements have nearly tripled since passage of the Dietary Supplement Health and Education Act in 1994. Many people interpret “natural” as “safe” and, with conventional healthcare costs rising, have turned to supplements to alleviate symptoms and reap perceived benefits. 

In fact, little is known about how natural products may alter the therapeutic effects and safety of prescription and over-the-counter medications. 

Pharmacists have had to counsel patients about herbal supplements’ safety, but without the benefit of reliable data and definitive guidance, said Sean Sullivan, UW professor and dean of the School of Pharmacy.  

Wort

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Studies in the late 1990's showed that St. John’s wort and grapefruit juice had dangerous interactions with a variety of medications.

picture of St. John's wort flower and supplement pill form

With this backdrop, researchers from the University of Washington, Washington State University and the University of North Carolina at Greensboro are partnering to study potential interactions between select natural products and commonly used medications. Their collaborative Natural Product Drug Interaction Center was funded by a $10 million, five-year grant from National Institutes of Health (NIH).

“Interactions can range from mild to severe or even life-threatening. So far, the data in the field has been highly variable in quality and/or relatively sparse,” said Craig Hopp, who oversees this complementary and integrative health grant program at NIH. 

The center’s goals are to assess existing gaps in scientific literature, investigate natural products’ interactions with common medications; establish standards in this study area; and develop a public database of information.

The pharmacology team, led by Dr. Mary Paine of WSU, will identify and prioritize the four to six products to be studied, including green tea and cannabinoids (marijuana), seek to uncover the mechanisms of natural product-drug interactions, and design appropriate preclinical and clinical studies to address scientific gaps.

The analytical team, led by Dr. Nicholas Oberlies at UNCG, will acquire the materials for study and ensure their consistency and sufficient supply. Drs. Danny Shen and Jeannine McCune at UW will lead the center’s administration, developing and disseminating best practices. The informatics team, led by Dr. Isabelle Ragueneau-Majlessi of UW, will create a data and information repository available to researchers, practitioners and the public through a website, app and blog. 

The center plans to have initial results available within two years. The grant was funded under a cooperative agreement award (1U54AT008909-01).