Clinical Evaluation of the Pharmacokinetic Goldenseal-Metformin Interaction in Diabetic Patients

Summary

Supplements containing goldenseal, a perennial herb native to North America, have consistently ranked among the top 20 highest selling natural products throughout the last decade. Goldenseal products are marketed as licensed natural health products in Canada and as dietary supplements in the United States. Natural products made from dried roots of the goldenseal plant are purported to have therapeutic value and are used to self-treat a range of medical complications, including the common cold, allergic rhinitis, and digestive disorders, such as diarrhea and constipation. Based on a previous clinical study, goldenseal have been shown to precipitate pharmacokinetic interactions with metformin in healthy volunteers. This follow-up study aims to evaluate the goldenseal-metformin interaction in type 2 diabetic patients. Results from this proposed clinical study will (1) characterize the pharmacokinetic interaction between the botanical dietary supplement goldenseal and anti-diabetic drug metformin, (2) provide evidence-based recommendations to mitigate drug interaction risks, and (3) contribute to the development of a comprehensive strategy for effectively assessing other potential natural-product drug interactions.

Timeline

Start

2021-09-16

Primary completion

2023-01-16

Completion

2023-08-31

Outcome

Met primary endpoint

paper of 0.93 [0.86-1.01] laying within the predefined no-effect range (0.80-1.25). PMID 39943692 ↗

Publications

• Background Nguyen JT, Tian DD, Tanna RS, Hadi DL, Bansal S, Calamia JC, Arian CM, Shireman LM, Molnar B, Horvath M, Kellogg JJ, Layton ME, White JR, Cech NB, Boyce RD, Unadkat JD, Thummel KE, Paine MF. Assessing Transporter-Mediated Natural Product-Drug Interactions Via In vitro-In Vivo Extrapolation: Clinical Evaluation With a Probe Cocktail. Clin Pharmacol Ther. 2021 May;109(5):1342-1352. doi: 10.1002/cpt.2107. Epub 2020 Dec 23.
• Background Liang X, Giacomini KM. Transporters Involved in Metformin Pharmacokinetics and Treatment Response. J Pharm Sci. 2017 Sep;106(9):2245-2250. doi: 10.1016/j.xphs.2017.04.078. Epub 2017 May 8.
• Nguyen JT, Arian CM, Tanna RS, Cherel MG, Layton ME, White JR, Thummel KE, Paine MF. The Pharmacokinetic Interaction Between Metformin and the Natural Product Goldenseal Is Metformin Dose-Dependent: A Three-Arm Crossover Study in Adults With Type 2 Diabetes. Clin Transl Sci. 2025 Feb;18(2):e70120. doi: 10.1111/cts.70120.

Drugs

Indications