Evening Primrose Ingredients & Drug Interactions
by Herbal Terra
What is this page for?
First and foremost: checking Evening Primrose against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.
Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy
Evening Primrose is a dietary supplement by Herbal Terra with 1 active ingredient. Its ingredients are commonly taken for eczema and skin health, pms symptoms, breast pain (mastalgia).Based on those ingredients, 233 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are certified organic Evening Primrose (Oenthera biennis) flower liquid extract. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.
Check Your Meds Against Evening Primrose by Herbal Terra
Ask about any prescription or over-the-counter medication and we check it for interactions with Evening Primrose by Herbal Terra — and tell you which ingredient is responsible.
AI summaries are generated from our interaction database for education only — always confirm with your pharmacist. How we use AI
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HelloPharmacist Scorecard of Evening Primrose by Herbal Terra
Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.
What’s inside
Full disclosure
This product contains one active ingredient: certified organic evening primrose flower liquid extract. Evening primrose oil is rich in gamma-linolenic acid (GLA), a fatty acid with potential effects on inflammation, platelet function, and other body processes.
The only other ingredient is menstruum, a liquid used to extract and preserve the plant material.
Does it work?
Couldn't assess
The evidence for evening primrose oil is mixed and often limited. For asthma, it's rated possibly ineffective.
For mastalgia (breast pain), the evidence suggests it's likely ineffective. For other uses listed in our data—abortion, acne, hysteroscopy, and ADHD—there isn't enough reliable evidence yet to rate its effectiveness.
Talk with your pharmacist or doctor if you're considering this for a specific condition.
How safe is it?
Well-documented data
Evening primrose oil is generally well tolerated when used short-term. The most common side effects are digestive: abdominal pain, bloating, diarrhea, upset stomach, nausea, and vomiting.
Dizziness, headache, skin rash, and acne have also been reported. Long-term safety data are limited.
During pregnancy, the safety evidence is unclear and some reports raise concerns, so it's best avoided unless your doctor directs otherwise. During lactation, there isn't enough data to know either way—talk with your doctor or pharmacist for personalized advice.
Meds to double-check
Moderate interaction found
Before taking Herbal Terra Evening Primrose, double-check with your pharmacist if you're on blood thinners or antiplatelet drugs (like warfarin or aspirin), lithium, phenothiazines (antipsychotics), or lopinavir/ritonavir for HIV. Also mention any drugs processed by CYP2C9 in your liver, as evening primrose may affect their levels.
The bottom line
Scorecard at a glanceFully disclosed formula with no assessable stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.
Evening primrose oil may be considered by people looking to address specific health concerns, but the evidence for most uses is weak or absent. If you take blood thinners, lithium, antipsychotics, HIV medications, or many other drugs, you need to check this product with your pharmacist first—the interaction risks are real.
Pregnant women should avoid it unless their doctor says otherwise.
Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI
Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Sep 25, 2020.
This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed
General information
Key facts about Evening Primrose, straight from the product label.
| Brand | Herbal Terra |
|---|---|
| Barcode (UPC) | 0617503381316 |
| Net contents | 4 Fluid Ounce(s); 120 mL |
| Market status | On market |
| Date entered into DSLD | Sep 25, 2020 |
| DSLD ID | 233937 |
| Product type | Botanical |
| Supplement form | Liquid |
| Dietary claims / uses | All Other, Structure/Function |
| Intended target group(s) | Adult (18 - 50 Years), Organic, Gluten Free, Sugar Free |
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.
Supplement Facts
The label details for Evening Primrose by Herbal Terra, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| certified organic Evening Primrose (Oenthera biennis) flower liquid extract | 970 mg | -- |
Other ingredients: Menstruum
Tap any ingredient to jump to its full detail below.
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Suggested/Recommended/Usage/Directions
Direction Shake well before use. Adults take up to 30 drops (1 mL, one full squeeze of the dropper bulb) in 3-4 fl. oz of juice or water up to 4 times a day. We recommend to seek expert medical advice before taking this or any other herbal supplements.
FDA Disclaimer Statement
Notice This product has not been evaluated by the FDA and is not intended to diagnose, treat, cure, or prevent any disease.
Formulation
Manufactured in the USA in an FDA registered facility
Sugar free
Dried herb/menstruum ratio: 1:3 Expertly extracted Laboratory tested 330 mg/1 mL Premium product Super concentrated liquid herbal extract
Non GMO
No artificial ingredients, GMO, gluten, color additives, fillers, preservatives or binders. Natural Gluten Free
Precautions
Caution May have contraindications.
Do not use if you are allergic to any ingredients.
Consult a physician before using during pregnancy, if nursing, or if you are on any medications.
Keep out of the reach of children.
Storage
Store in a cool, dry, dark place.
Formula
Oenothera biennis
FDA Statement of Identity
Herbal Supplement
Seals/Symbols
Made in USA Made in an FDA registered facility Natural Gluten Free
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
Evening Primrose by Herbal Terra label
The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.
Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.
View the full label (PDF)The Ingredients in Evening Primrose by Herbal Terra
This is the 1 active ingredient this product is made of. Select it to open its full monograph.
Serving size1 mL Dosage formLiquid Servings per container120 Amounts shown are per serving.
Certified organic Evening Primrose (Oenthera biennis) flower liquid extract
Interacts with233 drugs
Evening primrose oil is a seed oil rich in gamma-linolenic acid (GLA), an omega-6 fatty acid, that is popularly used for skin conditions, PMS, and bre...
Certified organic Evening Primrose (Oenthera biennis) flower liquid extract monograph & interactionsOther (inactive) ingredients: Menstruum. These complete the product’s ingredient list but are not active constituents.
Evening Primrose by Herbal Terra Drug Interactions
HelloPharmacist Interaction Report
Herbal Terra Evening Primrose contains evening primrose oil, which has documented interactions with several medication types.
The most serious is blood thinners and antiplatelet drugs—evening primrose oil may increase bleeding risk because it can thin the blood and prolong bleeding time.
Read the full breakdown — every affected drug type, severity by severity
Moderate concerns also exist with lithium (a mood stabilizer), where evening primrose oil may lower lithium levels and reduce its effect. Phenothiazines (antipsychotic drugs used for schizophrenia) carry a theoretical risk of seizures when combined with evening primrose oil.
There's also a documented case of evening primrose oil increasing lopinavir levels in an HIV patient taking this protease inhibitor.
A minor interaction exists with CYP2C9 substrate drugs—evening primrose oil may increase their levels and effects. Altogether, these interactions span 230 individual medications.
Before adding this product, use the medication checker below or talk with your pharmacist about your prescriptions.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against Evening Primrose?
Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.
Go to the checkerIngredients driving the most interactions
Individual Drug Interactions
The ingredients in Evening Primrose interact with 233 drugs. Click any drug to see the details.
1 of the 1 ingredient in Evening Primrose interact with drugs. Each result below shows which ingredient is responsible. certified organic Evening Primrose (Oenthera biennis) flower liquid extract
Aspirin, Caffeine, OrphenadrineInvagesic, Invagesic Forte, Norgesic, Norgesic Forte, Orphengesic, Orphengesic Forte
How Aspirin, Caffeine, Orphenadrine interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Caffeine, Orphenadrine interactionAspirin, Caffeine, Phenacetin, PropoxypheneMargesic Comp. 65
How Aspirin, Caffeine, Phenacetin, Propoxyphene interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Caffeine, Phenacetin, Propoxyphene interactionAspirin, Calcium Carbonate, Magnesium Carbonate, Magnesium OxideBufferin
How Aspirin, Calcium Carbonate, Magnesium Carbonate, Magnesium Oxide interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Calcium Carbonate, Magnesium Carbonate, Magnesium Oxide interactionAspirin, CarisoprodolSoma Compound
How Aspirin, Carisoprodol interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Carisoprodol interactionAspirin, Carisoprodol, Codeine PhosphateSoma Compound w/ Codeine
How Aspirin, Carisoprodol, Codeine Phosphate interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Carisoprodol, Codeine Phosphate interactionAspirin, Chlorpheniramine, PhenylpropanolamineAlka-Seltzer Plus Cold
How Aspirin, Chlorpheniramine, Phenylpropanolamine interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Chlorpheniramine, Phenylpropanolamine interactionAspirin, Citric Acid, Sodium BicarbonateAlka-Seltzer Pain Reliever and Antacid
How Aspirin, Citric Acid, Sodium Bicarbonate interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Citric Acid, Sodium Bicarbonate interactionAspirin, Codeine PhosphateAspirin w/ Codeine
How Aspirin, Codeine Phosphate interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Codeine Phosphate interactionAspirin, Codeine Phosphate, MethocarbamolRobaxisal C
How Aspirin, Codeine Phosphate, Methocarbamol interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Codeine Phosphate, Methocarbamol interactionAspirin, Codeine Phosphate, PhenobarbitalPhenaphen
How Aspirin, Codeine Phosphate, Phenobarbital interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Codeine Phosphate, Phenobarbital interactionAspirin, Diphenhydramine, PhenylpropanolamineAlka Seltzer Plus Night Time Effervescent
How Aspirin, Diphenhydramine, Phenylpropanolamine interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Diphenhydramine, Phenylpropanolamine interactionAspirin, DipyridamoleAggrenox, Asasantin Retard
How Aspirin, Dipyridamole interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Dipyridamole interactionAspirin, Ethoheptazine, MeprobamateEquagesic
How Aspirin, Ethoheptazine, Meprobamate interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Ethoheptazine, Meprobamate interactionAspirin, HydrocodoneAlor 5 500, Lortab ASA
How Aspirin, Hydrocodone interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Hydrocodone interactionAspirin, MeprobamateMicrainin
How Aspirin, Meprobamate interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Meprobamate interactionAspirin, MethocarbamolRobaxisal
How Aspirin, Methocarbamol interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Methocarbamol interactionAspirin, OmeprazoleYosprala
How Aspirin, Omeprazole interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractCytochrome P450 2c9 (cyp2c9) Substrates, Anticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose may increase the levels and clinical effects of CYP2C9 substrates.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Omeprazole interactionAspirin, OxycodonePercodan
How Aspirin, Oxycodone interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Oxycodone interactionAspirin, PentazocineTalwin Compound
How Aspirin, Pentazocine interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Aspirin, Pentazocine interactionBetrixabanBevyxxa
How Betrixaban interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Betrixaban interactionBivalirudinAngiomax, Angiomax Rtu, Angiox
How Bivalirudin interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Bivalirudin interactionBromfenac SodiumBromsite, Prolensa
How Bromfenac Sodium interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Bromfenac Sodium interactionCabliviCablivi
How Cablivi interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Cablivi interactionCangrelorKengreal
How Cangrelor interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Cangrelor interactionCarphenazineProketazin
How Carphenazine interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractPhenothiazines Moderate
Interaction Summary
Theoretically, taking evening primrose oil with phenothiazines might increase the risk of convulsions.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Carphenazine interactionChlorpromazineThorazine, Thorazine Spansules
How Chlorpromazine interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractPhenothiazines Moderate
Interaction Summary
Theoretically, taking evening primrose oil with phenothiazines might increase the risk of convulsions.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Chlorpromazine interactionCilostazolPletal
How Cilostazol interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Cilostazol interactionClopidogrelPlavix
How Clopidogrel interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractCytochrome P450 2c9 (cyp2c9) Substrates, Anticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose may increase the levels and clinical effects of CYP2C9 substrates.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Clopidogrel interactionCyamemazineTercian
How Cyamemazine interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractPhenothiazines Moderate
Interaction Summary
Theoretically, taking evening primrose oil with phenothiazines might increase the risk of convulsions.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Cyamemazine interactionDalteparinFragmin
How Dalteparin interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid ExtractAnticoagulant/antiplatelet Drugs Moderate
Interaction Summary
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Read the full Certified Organic Evening Primrose (oenthera Biennis) Flower Liquid Extract + Dalteparin interactionEach ingredient & the kinds of drugs it affects
For each ingredient in Evening Primrose with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.
certified organic Evening Primrose (Oenthera biennis) flower liquid extract
Anticoagulant/Antiplatelet Drugs
Theoretically, evening primrose oil may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Evening primrose oil contains gamma linolenic acid (GLA). There is preliminary clinical evidence that GLA can reduce platelet aggregation and prolong bleeding time.
Lithium
Theoretically, concomitant use of lithium with evening primrose oil might decrease lithium levels and effects.
In a case report, a patient on a stable dose of lithium for 10 years experienced a reduction in lithium levels after taking evening primrose oil 500 mg daily. Baseline levels were 0.69 mmol/L, which decreased to 0.37 mmol/L after 2 months and 0.23 mmol/L after 3 months of use. Lithium levels increased within 6 weeks of discontinuing evening primrose oil, to 0.73 mmol/L; no clinical effects were noted.
Lopinavir/Ritonavir (Kaletra)
Theoretically, evening primrose oil might increase the levels and effects of lopinavir.
In a case report, an HIV patient who took evening primrose oil (Efamol) along with lopinavir/ritonavir experienced an increase in serum levels of lopinavir to 15.2 mg/L. Six weeks after discontinuing evening primrose oil, levels of lopinavir returned to the normal range of 5-10 mg/L. When re-challenged with evening primrose oil for a week, the patient's lopinavir levels increased from 6.69 to 8.11 mg/L. It is suspected that evening primrose oil increases levels of lopinavir by inhibiting cytochrome P450 3A4 (CYP3A4), which metabolizes lopinavir. However, this effect has not been reported in other research.
Phenothiazines
Theoretically, taking evening primrose oil with phenothiazines might increase the risk of convulsions.
Evening primrose oil contains gamma-linolenic acid (GLA). There is some concern that taking supplements containing GLA might cause seizures, or lower the seizure threshold, when taken with phenothiazines. In one report, three patients with schizophrenia who had received phenothiazines developed EEG changes suggestive of temporal lobe epilepsy after starting treatment with GLA, although none experienced an actual seizure. In another report, two patients with schizophrenia who were stabilized on phenothiazines developed seizures when evening primrose oil 4 grams daily was added. One of these patients had a prior history of seizures. It is unclear whether evening primrose oil had any additive epileptogenic effects with the phenothiazines; there is no evidence that taking evening primrose oil alone causes seizures.
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.
Brand information
Manufacturer and brand details for Evening Primrose, from the product label.
Evening Primrose by Herbal Terra: Common Questions
Does Evening Primrose by Herbal Terra interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
What's in this bottle?
Does evening primrose oil actually work?
What side effects might I get?
Is it safe during pregnancy?
Can I take this while breastfeeding?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if Evening Primrose is safe with your meds?
Our pharmacists answer your medication & supplement questions — free.
Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.
The Full Monographs Behind Evening Primrose’s Ingredients
Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.
Sources & How We Checked
Evening Primrose's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.
- NIH Dietary Supplement Label Database (DSLD) — The official product label on file for this supplement.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference behind the ingredient interaction data.
Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.
The 33 references behind this product’s interaction data
Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.
Evening Primrose 33 references
- Shaw D, Leon C, Kolev S, Murray V. Traditional remedies and food supplements: a 5-year toxicological study (1991-1995). Drug Saf 1997;17:342-56.
- Laivuori H, Hovatta O, Viinikka L, et al. Dietary supplementation with primrose oil or fish oil does not change urinary excretion of prostacyclin and thromboxane metabolites in pre-eclamptic women. Prostaglandins Leukot Essent Fatty Acids 1993;49:691-4. PubMed
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