Diabetics On Metformin Should Avoid Goldenseal For This Reason

by DailyHealthPost Editorial

Diabetics who are prescribed metformin may be unknowingly sabotaging their efforts to maintain healthy blood sugar levels if they also take goldenseal. This discovery comes from a new study published in the journal Clinical Pharmacology & Therapeutics.

Metformin is the world’s most-prescribed oral glucose-lowering drug. The medication was included in a cocktail of selected drugs given to participants in a clinical study led by scientists at Washington State University’s College of Pharmacy and Pharmaceutical Sciences. 

The purpose of the study was to determine the impact of goldenseal on specific drug transporters in the body. For those who might not know, drug transporters facilitate absorption or expulsion of drug molecules in different tissues such as the intestine, liver, kidney and brain.


“After six days of taking goldenseal, participants had about 25 percent less metformin in their bodies, a statistically significant change that could potentially impact glucose control in patients with type 2 diabetes,” said James Nguyen, a Ph.D. candidate in pharmaceutical sciences and recent Doctor of Pharmacy graduate. 

He said the finding serves as a caution to health care providers and patients that over-the-counter natural product use can lead to unwanted drug interactions, which may lead to negative health outcomes. Unstable glucose levels increase patients’ risk of serious health complications, such as heart disease, kidney disease and infections.

Goldenseal is a perennial herb native to North America. It is often combined with Echinacea and sold as a herbal remedy used to self-treat the common cold and other respiratory tract infections. Goldenseal is also commonly used for digestive issues such as diarrhea and constipation as well as rashes and other skin problems.

As follow-up to the research, Nguyen plans to conduct studies to determine the mechanism by which goldenseal alters metformin absorption. Based on the data, he said that this appears to happen in the intestine and may be driven by the drug transporter OCT1. This research could eventually lead to the discovery of other natural product-drug interactions involving goldenseal and drugs transported by OCT1.

For more information on this story, visit this link here.