Phellodendron - Riomet ER (Metformin Hydrochloride) Interaction
Herbal: Phellodendron
Also Known As: Phellodendron amurense, Amur Cork Bark, Amur Cork Tree, Amur Corktree, Corktree, Cortex Phellodendri, Huang Bai, Huang Bo, Huangbai, Phellodendri Cortex
Drug: Metformin Hydrochloride
Brand names:
Riomet ER
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
May 04, 2025
Interaction Details
Metformin Hydrochloride is classified as belonging to the following category: Antidiabetes Drugs
Theoretically, phellodendron may increase the risk of hypoglycemia when taken with antidiabetes drugs.
Phellodendron contains berberine. Clinical research shows that berberine may lower blood glucose levels. Theoretically, phellodendron might also lower blood glucose levels.
Interaction Rating
Likelihood of Occurrence
PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
References
- Zhang Y, Li X, Zou D, et al. Treatment of type 2 diabetes and dyslipidemia with the natural plant alkaloid berberine. J Clin Endocrinol Metab 2008;93:2559-65.
- Yin, J., Xing, H., and Ye, J. Efficacy of berberine in patients with type 2 diabetes mellitus. Metabolism 2008;57(5):712-717.
- Zhang, H., Wei, J., Xue, R., Wu, J. D., Zhao, W., Wang, Z. Z., Wang, S. K., Zhou, Z. X., Song, D. Q., Wang, Y. M., Pan, H. N., Kong, W. J., and Jiang, J. D. Berberine lowers blood glucose in type 2 diabetes mellitus patients through increasing insulin re
- Wei, W., Zhao, H., Wang, A., Sui, M., Liang, K., Deng, H., Ma, Y., Zhang, Y., Zhang, H., and Guan, Y. A clinical study on the short-term effect of berberine in comparison to metformin on the metabolic characteristics of women with polycystic ovary syndro
Interaction Details
Metformin Hydrochloride is classified as belonging to the following category: Metformin (Glucophage)
Theoretically, phellodendron might increase the therapeutic and adverse effects of metformin.
Phellodendron contains berberine. In vitro and animal studies show that berberine can increase the systemic exposure and half-life of metformin, potentially increasing metformin's effects and side effects. This interaction seems to be most apparent when berberine is administered 2 hours prior to metformin. Taking berberine and metformin at the same time does not appear to increase systemic exposure to metformin. It is unclear if phellodendron might have this same effect.
Interaction Rating
Likelihood of Occurrence
PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
References
- Lyu Y, Zhang Y, Yang M, et al. Pharmacokinetic interactions between metformin and berberine in rats: Role of oral administration sequences and microbiota. Life Sci. 2019;235:116818.
Phellodendron Overview
Phellodendron amurense, also known as Amur cork tree, is a deciduous tree native to China, Korea, and Japan. It belongs to the Rutaceae family and is valued for its medicinal properties. The bark of Phellodendron amurense is used in traditional Chinese medicine for its purported anti-inflammatory, antimicrobial, and antioxidant effects. It contains compounds such as berberine, which is believed to contribute to its therapeutic properties. Phellodendron amurense has been studied for its potential to manage conditions like diabetes, inflammation, and cancer.
Phellodendron - More Interactions
Phellodendron interacts with 1134 drugs
Interaction Rating Key
These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.
| Major | The combined use of these agents is strongly discouraged as serious side effects or other negative outcomes could occur. |
| Moderate | Use cautiously under the care of a healthcare professional or avoid this combination. A significant interaction or negative outcome could occur. |
| Minor | Be aware that there is a chance of an interaction. Watch for warning signs of a potential interaction. |
| Unknown | No interactions have been reported or no interaction data is currently available. |
Return to the main supplement interaction checker page
Parts of this content are provided by the Therapeutic Research Center, LLC.
DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.
© 2021 Therapeutic Research Center, LLC
Drug descriptions are provided by MedlinePlus.
Ask A Pharmacist About Your Herbal Questions!
Dr. Brian Staiger, PharmD
In addition to being a clinical pharmacist specializing in pharmacotherapy, Dr. Brian Staiger is a registered herbalist through the American Herbalist Guild. He has combined his passion for pharmacy practice with the study of medical ethnobotany to improve patient care. Feel free to reach out about any of your herbal or medication questions!
Ask A Pharmacist