Oregon Grape - Dificid (Fidaxomicin) Interaction
Herbal: Oregon Grape
Also Known As: Mahonia aquifolium, Barberry, Berberis, Blue Barberry, Creeping Barberry, Holly Barberry, Holly Mahonia, Holly-Leaved Berberis, Mahonia, Mahonia Faux Houx, Mahonia à Feuilles de Houx, Mahonie, Mountain-Grape, Oregon Barberry, Oregon Grape-Holly, Scraperoot
Drug: Fidaxomicin
Brand names:
Dificid

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
May 04, 2025
Interaction Details
Fidaxomicin is classified as belonging to the following category: P-Glycoprotein Substrates
Theoretically, Oregon grape might increase serum levels of drugs that are P-glycoprotein (P-gp) substrates.
In vitro research suggests that Oregon grape extracts inhibit P-gp efflux.
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
- Fan Y, Zhou Z, Zhang L. Effect of Oregon grape root extracts on P-glycoprotein mediated transport in in vitro cell lines. J Pharm Pharm Sci 2024;26:11927.
Oregon Grape Overview

Fidaxomicin Overview
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Fidaxomicin is used to treat diarrhea caused by Clostridium difficile (C. difficile; a type of bacteria that may cause severe or life-threatening diarrhea) in adults and children 6 months of age and older. Fidaxomicin is in a class of medications called macrolide antibiotics. It works by killing bacteria in the intestines.
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Fidaxomicin will not treat infections in any other part of the body. Antibiotics such as fidaxomicin will not work for colds, flu, or other viral infections. Taking antibiotics when they are not needed increases your risk of getting an infection later that resists antibiotic treatment.
Oregon Grape - More Interactions
Oregon Grape interacts with 1189 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. |
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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.