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 Evening Primrose Herb Extract, Dry. 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: Evening Primrose Herb Extract in dry form. Evening primrose is a plant whose oil and seed extracts are used as a supplement, though the evidence for most uses is limited or weak.
The liquid form also contains alcohol, water, and glycerin as inactive ingredients.
Does it work?
Couldn't assess
The evidence for evening primrose is mixed to poor. It's rated possibly ineffective for asthma and likely ineffective for breast pain (mastalgia).
For acne, ADHD, abortion support, and use during hysteroscopy, there isn't enough reliable evidence yet to say whether it works or doesn't. If you're considering it for one of these reasons, talk with your doctor or pharmacist about whether the limited evidence supports its use for your situation.
How safe is it?
Well-documented data
Evening primrose oil is generally well tolerated in the short term, though quality evidence and long-term safety data are limited. The most common side effects when taken by mouth are stomach upset — abdominal pain, bloating, diarrhea, indigestion, gas, nausea, and vomiting.
Dizziness, headache, skin rash, and acne have also been reported. During pregnancy, the safety data is unclear and some reports raise concerns, so it's best avoided unless your doctor directs you to take it.
Lactation safety data is also incomplete; talk with your pharmacist for personalized advice if you're nursing.
Meds to double-check
Moderate interaction found
Before you start, double-check with your pharmacist if you're taking blood thinners or antiplatelet drugs (like warfarin or aspirin) — there's a Moderate risk of increased bleeding. Also mention if you take lithium, phenothiazines (antipsychotics), lopinavir/ritonavir (Kaletra), or any drugs cleared by the CYP2C9 pathway.
No interactions are documented for other drug classes, but that's not a guarantee none exist.
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 may be considered for conditions where you've discussed it with your doctor, but the evidence is weak for most uses. Anyone taking blood thinners, lithium, HIV medications, antipsychotics, or drugs metabolized by CYP2C9 should check with their pharmacist first.
Pregnant women should avoid it unless directed otherwise by a doctor.
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 Mar 25, 2025.
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) | 1977490017308 |
| Net contents | 4 Fluid Ounce(s); 120 mL |
| Market status | On market |
| Date entered into DSLD | Mar 25, 2025 |
| DSLD ID | 326972 |
| Product type | Botanical |
| Supplement form | Liquid |
| Dietary claims / uses | All Other, Structure/Function |
| Intended target group(s) | Adult (18 - 50 Years), 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 |
|---|---|---|
| Evening Primrose Herb Extract, Dry | 983 mg | -- |
Other ingredients: Alcohol, Water, Glycerin
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
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.
Precautions
We recommend to seek expert medical advice before taking. May have contraindications and cause adverse reaction.
Consult a physician before giving to children under 18, before using during pregnancy, if nursing, or if you are on any medications.
Consult a physician before giving to children under 18, before using during pregnancy, if nursing, or if you are on any medications. Keep out of the reach of children!
Do not use if you are allergic to any ingredients.
Storage
Store in a cool, dry, dark place.
FDA Disclaimer Statement
This product has not been evaluated by the FDA and is not intended to diagnose, treat, cure or prevent any disease.
Formulation
cGMP Made in compliance with cGMP 21 CFR 111 in an FDA registered and inspected facility.
Sugar free
Expertly extracted 100% natural Premium product
Organic alcohol
No artificial ingredients, color additives, fillers or binders.
Natural Gluten free
Formula
Oenothera biennis
Organic alcohol
FDA Statement of Identity
Herbal Supplement
Seals/Symbols
Made in USA
General Statements
Organic raw material.
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.
Evening Primrose Herb Extract, Dry
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...
Evening Primrose Herb Extract, Dry monograph & interactionsOther (inactive) ingredients: Alcohol, Water, Glycerin. These complete the product’s ingredient list but are not active constituents.
Evening Primrose by Herbal Terra Drug Interactions
HelloPharmacist Interaction Report
Herbal Terra's Evening Primrose can interact with several classes of medications.
The most serious concern is with blood thinners and antiplatelet drugs (like warfarin and aspirin), where the herb may increase bleeding risk because its gamma-linolenic acid can reduce how quickly blood clots.
Read the full breakdown — every affected drug type, severity by severity
It also interacts Moderately with lithium — a case report showed that evening primrose oil lowered lithium levels by nearly half over two months, which could reduce how well the mood stabilizer works. Similarly, it may increase levels of the HIV medication lopinavir/ritonavir (Kaletra) and raise the seizure risk if you take phenothiazines (antipsychotics used for schizophrenia).
Additionally, evening primrose may increase levels of certain drugs metabolized by the CYP2C9 enzyme pathway — a Minor interaction that affects how your body clears them.
Altogether, these interactions span 230 individual medications. Use the medication checker below to verify your exact prescriptions before starting this product.
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. Evening Primrose Herb Extract, Dry
Icosapent Ethyl (prescription Drug)Vascepa
How Icosapent Ethyl (prescription Drug) interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryAnticoagulant/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 Evening Primrose Herb Extract, Dry + Icosapent Ethyl (prescription Drug) interactionIloprostAurlumyn, Ventavis
How Iloprost interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryAnticoagulant/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 Evening Primrose Herb Extract, Dry + Iloprost interactionInotersenTegsedi
How Inotersen interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryAnticoagulant/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 Evening Primrose Herb Extract, Dry + Inotersen interactionIsopropamide, ProchlorperazineCombid
How Isopropamide, Prochlorperazine interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryPhenothiazines Moderate
Interaction Summary
Theoretically, taking evening primrose oil with phenothiazines might increase the risk of convulsions.
Read the full Evening Primrose Herb Extract, Dry + Isopropamide, Prochlorperazine interactionIsopropamide, TrifluoperazineStelabid Forte, Stelabid No 1, Stelabid No 2
How Isopropamide, Trifluoperazine interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryPhenothiazines Moderate
Interaction Summary
Theoretically, taking evening primrose oil with phenothiazines might increase the risk of convulsions.
Read the full Evening Primrose Herb Extract, Dry + Isopropamide, Trifluoperazine interactionKetoprofenOrudis, Oruvail Gel, Oruvail Injection, Powergel
How Ketoprofen interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryAnticoagulant/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 Evening Primrose Herb Extract, Dry + Ketoprofen interactionLepirudinRefludan
How Lepirudin interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryAnticoagulant/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 Evening Primrose Herb Extract, Dry + Lepirudin interactionLithium Carbonate (prescription Drug)Eskalith, Lithium Carbonate
How Lithium Carbonate (prescription Drug) interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryLithium Moderate
Interaction Summary
Theoretically, concomitant use of lithium with evening primrose oil might decrease lithium levels and effects.
Read the full Evening Primrose Herb Extract, Dry + Lithium Carbonate (prescription Drug) interactionLopinavir, RitonavirKaletra
How Lopinavir, Ritonavir interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryLopinavir/ritonavir (kaletra) Moderate
Interaction Summary
Theoretically, evening primrose oil might increase the levels and effects of lopinavir.
Read the full Evening Primrose Herb Extract, Dry + Lopinavir, Ritonavir interactionMeperidine, PromethazineMepergan, Meprozine
How Meperidine, Promethazine interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryPhenothiazines Moderate
Interaction Summary
Theoretically, taking evening primrose oil with phenothiazines might increase the risk of convulsions.
Read the full Evening Primrose Herb Extract, Dry + Meperidine, Promethazine interactionMinocyclineAcnamino MR, Aknemin, Amzeeq, Arestin Miscrosperes, Dynacin, Minocin +6 more
How Minocycline interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryAnticoagulant/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 Evening Primrose Herb Extract, Dry + Minocycline interactionNadroparinFraxiparine
How Nadroparin interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryAnticoagulant/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 Evening Primrose Herb Extract, Dry + Nadroparin interactionNaproxenAleve, Anaprox, Anaprox DS, Arthroxen, EC-Naprosyn, Naprelan +7 more
How Naproxen interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryCytochrome 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 Evening Primrose Herb Extract, Dry + Naproxen interactionNaproxen SodiumMidol Extended Relief
How Naproxen Sodium interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryCytochrome 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 Evening Primrose Herb Extract, Dry + Naproxen Sodium interactionNaproxen, PseudoephedrineAleve Cold and Sinus
How Naproxen, Pseudoephedrine interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryCytochrome 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 Evening Primrose Herb Extract, Dry + Naproxen, Pseudoephedrine interactionNaproxen, SumatriptanTreximet
How Naproxen, Sumatriptan interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryCytochrome 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 Evening Primrose Herb Extract, Dry + Naproxen, Sumatriptan interactionNintedanib EsylateOfev
How Nintedanib Esylate interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryAnticoagulant/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 Evening Primrose Herb Extract, Dry + Nintedanib Esylate interactionNirmatrelvir, RitonavirPaxlovid
How Nirmatrelvir, Ritonavir interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryLopinavir/ritonavir (kaletra) Moderate
Interaction Summary
Theoretically, evening primrose oil might increase the levels and effects of lopinavir.
Read the full Evening Primrose Herb Extract, Dry + Nirmatrelvir, Ritonavir interactionNusinersen SodiumSpinraza
How Nusinersen Sodium interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryAnticoagulant/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 Evening Primrose Herb Extract, Dry + Nusinersen Sodium interactionOmbitasvir, Paritaprevir RitonavirTechnivie
How Ombitasvir, Paritaprevir Ritonavir interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryLopinavir/ritonavir (kaletra) Moderate
Interaction Summary
Theoretically, evening primrose oil might increase the levels and effects of lopinavir.
Read the full Evening Primrose Herb Extract, Dry + Ombitasvir, Paritaprevir Ritonavir interactionOmbitasvir, Paritaprevir, Ritonavir, DasabuvirViekira Pak
How Ombitasvir, Paritaprevir, Ritonavir, Dasabuvir interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryLopinavir/ritonavir (kaletra) Moderate
Interaction Summary
Theoretically, evening primrose oil might increase the levels and effects of lopinavir.
Read the full Evening Primrose Herb Extract, Dry + Ombitasvir, Paritaprevir, Ritonavir, Dasabuvir interactionOmega-3 Fatty Acids (prescription Drug)Lovaza
How Omega-3 Fatty Acids (prescription Drug) interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryAnticoagulant/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 Evening Primrose Herb Extract, Dry + Omega-3 Fatty Acids (prescription Drug) interactionPazopanibVotrient
How Pazopanib interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryAnticoagulant/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 Evening Primrose Herb Extract, Dry + Pazopanib interactionPentoxifyllineTrental
How Pentoxifylline interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryAnticoagulant/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 Evening Primrose Herb Extract, Dry + Pentoxifylline interactionPericyazinePericyazine
How Pericyazine interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryPhenothiazines Moderate
Interaction Summary
Theoretically, taking evening primrose oil with phenothiazines might increase the risk of convulsions.
Read the full Evening Primrose Herb Extract, Dry + Pericyazine interactionPerphenazineTrilafon
How Perphenazine interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryPhenothiazines Moderate
Interaction Summary
Theoretically, taking evening primrose oil with phenothiazines might increase the risk of convulsions.
Read the full Evening Primrose Herb Extract, Dry + Perphenazine interactionPhenprocoumonLiquamar
How Phenprocoumon interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryAnticoagulant/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 Evening Primrose Herb Extract, Dry + Phenprocoumon interactionPiroxicamFeldene, Feldene Gel
How Piroxicam interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryCytochrome 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 Evening Primrose Herb Extract, Dry + Piroxicam interactionProchlorperazineCompazine, Prochlor
How Prochlorperazine interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryPhenothiazines Moderate
Interaction Summary
Theoretically, taking evening primrose oil with phenothiazines might increase the risk of convulsions.
Read the full Evening Primrose Herb Extract, Dry + Prochlorperazine interactionPromazineSparine
How Promazine interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryPhenothiazines Moderate
Interaction Summary
Theoretically, taking evening primrose oil with phenothiazines might increase the risk of convulsions.
Read the full Evening Primrose Herb Extract, Dry + Promazine 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.
Evening Primrose Herb Extract, Dry
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.
Herbal Terra
See all Herbal Terra products- Name
- Herbal Terra LLC
- Phone Number
- +18083857868
- Web Address
- herbalterra.com
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?
Is evening primrose safe during pregnancy?
Is evening primrose safe while breastfeeding?
What side effects might I notice?
Does evening primrose actually work for anything?
What are the inactive ingredients?
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
- Dove D, Johnson P. Oral evening primrose oil: its effect on length of pregnancy and selected intrapartum outcomes in low-risk nulliparous women (abstract). J Nurse Midwifery 1999;44:320-4. PubMed
- Guivernau M, Meza N, Barja P, Roman O. Clinical and experimental study on the long-term effect of dietary gamma-linolenic acid on plasma lipids, platelet aggregation, thromboxane formation, and prostacyclin production. Prostaglandins Leukot Essent Fatty A PubMed
- Cant A, Shay J, Horrobin DF. The effect of maternal supplementation with linoleic and gamma- linolenic acids on the fat composition and content of human milk: a placebo-controlled trial. J Nutr Sci Vitaminol (Tokyo) 1991;37:573-9. PubMed
- Keen H, Payan J, Allawi J, et al. Treatment of diabetic neuropathy with gamma-linolenic acid. The gamma-Linolenic Acid Multicenter Trial Group. Diabetes Care 1993;16:8-15.
- Blommers J, de Lange-De Klerk ES, Kuik DJ, et al. Evening primrose oil and fish oil for severe chronic mastalgia: a randomized, double-blind, controlled trial. Am J Obstet Gynecol 2002;187:1389-94.. DOI
- Cheung KL. Management of cyclical mastalgia in oriental women: pioneer experience of using gamolenic acid (Efamast) in Asia. Aust N Z J Surg 1999;69:492-4..
- Das UN. The lipids that matter from infant nutrition to insulin resistance. Prostaglandins Leukot Essent Fatty Acids 2002;67:1-12. PubMed
- Wedig KE, Whitsett JA. Down the primrose path: petechiae in a neonate exposed to herbal remedy for parturition. J Pediatr 2008;152:140, 140.e1. PubMed
- Ty-Torredes KA. The effect of oral evening primrose oil on bishop score and cervical length amongst term gravidas. Am J Obstet Gynecol. 2006;195(6 Suppl 1):S30.
- Moodley J and Norman RJ. Attempts at dietary alteration of prostaglandin pathways in the management of pre-eclampsia. Prostaglandins Leukot Essent Fatty Acids 1989;37(3):145-147. PubMed
- Tong M. [Treatment of hyperlipemia with evening primrose oil capsules]. Zhong Xi Yi Jie He Za Zhi. 1988;8:469-71, 452-3.
- Holman CP and Bell AF. A trial of evening primrose oil in the treatment of chronic schizophrenia. J Orhtomolecular Psych 1983;12:302-304.
- Vaddadi KS. The use of gamma-linolenic acid and linoleic acid to differentiate between temporal lobe epilepsy and schizophrenia. Prostaglandins Med 1981;6(4):375-379. PubMed
- 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. PubMed
- Yoon, S., Lee, J., and Lee, S. The therapeutic effect of evening primrose oil in atopic dermatitis patients with dry scaly skin lesions is associated with the normalization of serum gamma-interferon levels. Skin Pharmacol Appl.Skin Physiol 2002;15(1):20- PubMed
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