Evening Primrose - Singulair (Montelukast Sodium) Interaction
Herbal: Evening Primrose
Also Known As: Oenothera biennis, Oenothera muricata, Oenothera rubricaulis, Evening star, Suncups, Sundrop
Drug: Montelukast Sodium
Brand names:
Singulair
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Jun 15, 2025
Interaction Details
Montelukast Sodium is classified as belonging to the following category: Cytochrome P450 2C9 (Cyp2C9) Substrates
Theoretically, evening primrose may increase the levels and clinical effects of CYP2C9 substrates.
In vitro research shows that linoleic acid, a constituent of evening primrose oil, inhibits CYP2C9.
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
- Zou L, Harkey MR, and Henderson GL. Effects of herbal components on cDNA-expressed cytochrome P450 enzyme catalytic activity. Life Sci 8-16-2002;71(13):1579-1589.
Evening Primrose Overview
Evening primrose (Oenothera biennis) is a plant native to North and Central America and a member of the Onagraceae family. It is an annual plant that has bright yellow flowers that bloom in the evening (hence the name). The plant produces seeds that are rich in a fatty acid called gamma-linolenic acid (GLA).
Evening primrose oil is a dietary supplement that is derived from the seeds of the evening primrose plant. It is rich in GLA (gamma-linolenic acid), an omega-6 fatty acid, and is sometimes taken to improve the health of the skin, reduce inflammation, and reduce the symptoms of premenstrual syndrome (PMS). It has also been used historically for alcohol use disorder.
Dietary supplements containing evening primrose oil generally are standardized by their gamma-linolenic acid (GLA) and linoleic acid (LA) content.
Montelukast Sodium Overview
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Montelukast is used to prevent wheezing, difficulty breathing, chest tightness, and coughing caused by asthma in adults and children 12 months of age and older. Montelukast is also used to prevent bronchospasm (breathing difficulties) during exercise in adults and children 6 years of age and older. Montelukast is also used to treat the symptoms of seasonal (occurs only at certain times of the year), allergic rhinitis (a condition associated with sneezing and stuffy, runny or itchy nose) in adults and children 2 years of age and older, and perennial (occurs all year round) allergic rhinitis in adults and children 6 months of age and older. Montelukast should be used to treat seasonal or perennial allergic rhinitis only in adults and children who cannot be treated with other medications. Montelukast is in a class of medications called leukotriene receptor antagonists (LTRAs). It works by blocking the action of substances in the body that cause the symptoms of asthma and allergic rhinitis.
Evening Primrose - More Interactions
Evening Primrose interacts with 229 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.
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