Feverfew - Dextromethorphan HBr, Phenylephrine HCl Interaction
Herbal: Feverfew
Also Known As: Tanacetum parthenium, Altamisa, Bachelor's Buttons, Chrysanthème Matricaire, Featerfoiul, Featherfew, Featherfoil, Flirtwort Midsummer Daisy, Grande Camomille, Matricaria, Partenelle, Pyrèthre Doré, Pyrèthre Mousse, Santa Maria, Tanaceti Parthenii, Tanaisie Commune
Drug: Dextromethorphan HBr, Phenylephrine HCl
Brand names:
Vicks Formula 44D Cough & Head Congestion Relief

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
May 04, 2025
Interaction Details
Dextromethorphan HBr, Phenylephrine HCl is classified as belonging to the following category: Cytochrome P450 2D6 (Cyp2D6) Substrates
Theoretically, feverfew might increase levels of drugs metabolized by CYP2D6.
Laboratory research shows that feverfew might inhibit CYP2D6. So far, this interaction has not been reported in humans.
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
- Unger M, Frank A. Simultaneous determination of the inhibitory potency of herbal extracts on the activity of six major cytochrome P450 enzymes using liquid chromatography/mass spectrometry and automated online extraction. Rapid Commun Mass Spectrom 2004;1
Interaction Details
Dextromethorphan HBr, Phenylephrine HCl is classified as belonging to the following category: Cytochrome P450 3A4 (Cyp3A4) Substrates
Theoretically, feverfew might increase levels of drugs metabolized by CYP3A4.
Laboratory research shows that feverfew might inhibit CYP3A4. So far, this interaction has not been reported in humans.
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
- Unger M, Frank A. Simultaneous determination of the inhibitory potency of herbal extracts on the activity of six major cytochrome P450 enzymes using liquid chromatography/mass spectrometry and automated online extraction. Rapid Commun Mass Spectrom 2004;1
- Sil'vestrov VP, Kinitin AV, and Chesnokova, IV. [Immunological and metabolic disorders and the means for their correction in patients with chronic bronchitis]. Ter.Arkh. 1991;63:7-11.
Feverfew Overview

Feverfew - More Interactions
Feverfew interacts with 903 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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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.