Evening Primrose Ingredients & Drug Interactions
by Hawaii Pharm
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 Hawaii Pharm 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 Hawaii Pharm
Ask about any prescription or over-the-counter medication and we check it for interactions with Evening Primrose by Hawaii Pharm — 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 Hawaii Pharm
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, Dry. Evening primrose is a plant whose oil and extract are used in herbal medicine, primarily as a source of gamma linolenic acid (GLA), a fatty acid thought to have anti-inflammatory and other effects.
The liquid also contains alcohol, water, and glycerin as inactive ingredients.
Does it work?
Couldn't assess
The evidence for evening primrose is mixed and often limited. For asthma, it's rated possibly ineffective.
For breast pain (mastalgia), it's likely ineffective. For other uses listed here—abortion, acne, hysteroscopy, and ADHD—there isn't enough reliable evidence in our data to say whether it works or not.
Talk with your pharmacist about what you're hoping to treat and what the research actually shows for your specific concern.
How safe is it?
Well-documented data
Evening primrose oil is generally well tolerated in the short term, though 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.
Less common reports include skin rash, acne, dizziness, and headache. There is also a concern that it might lower the seizure threshold in people taking certain antipsychotics.
For pregnancy, the evidence is unclear and some reports raise concerns, so it's best avoided unless your doctor directs otherwise. For breastfeeding, safety data are also limited, so talk with your doctor or pharmacist before use.
Meds to double-check
Moderate interaction found
Check your medications if you take blood thinners or antiplatelet drugs (moderate interaction), lithium (moderate), antipsychotics called phenothiazines (moderate), lopinavir/ritonavir for HIV (moderate), or drugs processed by the liver enzyme CYP2C9 (minor). Use the search tool on this page with your exact medication names.
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 Herb Extract is generally well tolerated short-term, but the evidence for its effectiveness is weak or absent for most uses, and long-term safety data are limited. If you take blood thinners, lithium, antipsychotics, or HIV medications, you'll need to check with us before starting.
Talk with your pharmacist about whether this product makes sense for what you're trying to do.
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 Jun 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 | Hawaii Pharm |
|---|---|
| Barcode (UPC) | 840253621078 |
| Net contents | 4 Fluid Ounce(s); 120 Milliliter(s) |
| Market status | On market |
| Date entered into DSLD | Jun 25, 2025 |
| DSLD ID | 331873 |
| Product type | Botanical |
| Supplement form | Liquid |
| Dietary claims / uses | All Other, Structure/Function |
| Intended target group(s) | Adult (18 - 50 Years), Gluten 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 Hawaii Pharm, 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.
Brand IP Statement(s)
Hawaii Pharm Herbal Extract Highest Quality Since 2008
Suggested/Recommended/Usage/Directions
Suggested use: Shake well before using. For adults add about 20-30 drops (0.7-1 ml, one full squeeze of the dropper bulb) to some juice or water, up to 4 times a day.
Precautions
Warning: We recommend to seek expert medical advice before taking.
Do not use if you are allergic to any ingredients.
Consult your physician before giving to children under 18, during pregnancy, if nursing or taking medications.
Consult your physician before giving to children under 18, during pregnancy, if nursing or taking medications. Keep out of the reach of children!
May affect the ability to drive and operate machinery. May have contraindications, can cause side effects and adverse reactions. Do not use if seal is broken or missing.
Storage
Store in a cool dry place.
Seals/Symbols
cGMP Made in compliance with cGMP 21 CFR 111 in an FDA Registered and Inspected Facility.
USA Made in United States of America
FDA Disclaimer Statement
This product has not been evaluated by the FDA and is not intended to diagnose, treat, cure or prevent any disease.
General Statements
Scan this QR code to get more info or reorder
Formula
Oenothera biennis
Formulation
All the raw materials are gluten-free by their nature No artificial colors, flavors, or preservatives
Only natural ingredients Identity and purity is laboratory verified
C2H5OH Alcohol free
Made in USA, Hawaii
FDA Statement of Identity
Herbal Supplement
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
Evening Primrose by Hawaii Pharm 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 Hawaii Pharm
This is the 1 active ingredient this product is made of. Select it to open its full monograph.
Serving size0.7 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 Hawaii Pharm Drug Interactions
HelloPharmacist Interaction Report
Hawaii Pharm's Evening Primrose Herb Extract Liquid has documented interactions with several medication types.
The most serious concern is anticoagulants and antiplatelet drugs (blood thinners and drugs that prevent clots)—evening primrose contains a compound called gamma linolenic acid (GLA) that may reduce how fast blood clots, raising your bleeding risk if you're already on these medications.
Read the full breakdown — every affected drug type, severity by severity
You'll also want to check before combining this with lithium (used for mood disorders), phenothiazines (antipsychotics used for schizophrenia), or lopinavir/ritonavir (an HIV medication). Evening primrose may lower lithium levels, increase seizure risk with phenothiazines, and raise lopinavir levels higher than intended.
Additionally, evening primrose may increase levels of drugs metabolized by the enzyme CYP2C9, though this is a minor interaction.
Altogether, these interactions span 230 individual medications. We could not check an ingredient's interactions separately here because this product contains only one active ingredient.
Before you start, use the search tool below to run your exact medications against 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
AbciximabReoPro
How Abciximab 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 + Abciximab interactionAbrocitinibCibinqo
How Abrocitinib 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 + Abrocitinib interactionAcenocoumarolSintrom
How Acenocoumarol 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 + Acenocoumarol interactionAcepromazineAtravet
How Acepromazine 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 + Acepromazine interactionAcetaminophen, AspirinGemnisyn
How Acetaminophen, Aspirin 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 + Acetaminophen, Aspirin interactionAcetaminophen, Aspirin, CaffeineExcedrin, Excedrin Extra Strength, Excedrin Migraine
How Acetaminophen, Aspirin, Caffeine 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 + Acetaminophen, Aspirin, Caffeine interactionAcetaminophen, IbuprofenCombogesic
How Acetaminophen, Ibuprofen 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 + Acetaminophen, Ibuprofen interactionAcetylsalicylic AcidEntrophen
How Acetylsalicylic Acid 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 + Acetylsalicylic Acid interactionAlteplase, TpaActilyse, Activase
How Alteplase, Tpa 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 + Alteplase, Tpa interactionAluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium HydroxideAscriptin Codeine #2
How Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide 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 + Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide interactionAluminum Hydroxide, Aspirin, Magnesium HydroxideAscriptin
How Aluminum Hydroxide, Aspirin, Magnesium Hydroxide 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 + Aluminum Hydroxide, Aspirin, Magnesium Hydroxide interactionAmitriptyline, PerphenazineEtrafon, Etrafon-A, Etrafon-Forte, Triavil
How Amitriptyline, Perphenazine interacts with Evening Primrose — through 1 ingredient. Tap an ingredient for the detail:
Evening Primrose Herb Extract, DryCytochrome P450 2c9 (cyp2c9) Substrates, Phenothiazines Moderate
Interaction Summary
Theoretically, evening primrose may increase the levels and clinical effects of CYP2C9 substrates.
Read the full Evening Primrose Herb Extract, Dry + Amitriptyline, Perphenazine interactionAnacaulase-bcdbNexoBrid
How Anacaulase-bcdb 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 + Anacaulase-bcdb interactionAnagrelideAgrylin
How Anagrelide 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 + Anagrelide interactionAnisindioneMiradon
How Anisindione 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 + Anisindione interactionAntithrombin IiiThrombate III
How Antithrombin Iii 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 + Antithrombin Iii interactionApixabanEliquis
How Apixaban 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 + Apixaban interactionArgatrobanArgatroban
How Argatroban 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 + Argatroban interactionAspirinAngettes 75, ASA, Asaphen, Aspirin, Caprin, Cartia +8 more
How Aspirin 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 + Aspirin interactionAspirin, Aluminum Hydroxide, Codeine Phosphate, Magnesium HydroxideAscriptin Codeine #3
How Aspirin, Aluminum Hydroxide, Codeine Phosphate, Magnesium Hydroxide 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 + Aspirin, Aluminum Hydroxide, Codeine Phosphate, Magnesium Hydroxide interactionAspirin, ButalbitalAxotal
How Aspirin, Butalbital 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 + Aspirin, Butalbital interactionAspirin, Butalbital, CaffeineFiorinal
How Aspirin, Butalbital, Caffeine 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 + Aspirin, Butalbital, Caffeine interactionAspirin, Butalbital, Caffeine, Codeine PhosphateFiorinal w/ Codeine
How Aspirin, Butalbital, Caffeine, Codeine Phosphate 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 + Aspirin, Butalbital, Caffeine, Codeine Phosphate interactionAspirin, Butalbital, Caffeine, PhenacetinMarnal
How Aspirin, Butalbital, Caffeine, Phenacetin 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 + Aspirin, Butalbital, Caffeine, Phenacetin interactionAspirin, CaffeineAnacin
How Aspirin, Caffeine 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 + Aspirin, Caffeine interactionAspirin, Caffeine, Codeine PhosphateAnacin w/ Codeine
How Aspirin, Caffeine, Codeine Phosphate 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 + Aspirin, Caffeine, Codeine Phosphate interactionAspirin, Caffeine, Dihydrocodeine BitartrateSynalgos DC
How Aspirin, Caffeine, Dihydrocodeine Bitartrate 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 + Aspirin, Caffeine, Dihydrocodeine Bitartrate interactionAspirin, Caffeine, Dover's PwdAcedoval, Dovacet
How Aspirin, Caffeine, Dover's Pwd 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 + Aspirin, Caffeine, Dover's Pwd interactionAspirin, Caffeine, HydrocodoneDamason-P
How Aspirin, Caffeine, Hydrocodone 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 + Aspirin, Caffeine, Hydrocodone interactionAspirin, Caffeine, Isobutylallylbarbituric Acid, PhenacetinLanorinal
How Aspirin, Caffeine, Isobutylallylbarbituric Acid, Phenacetin 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 + Aspirin, Caffeine, Isobutylallylbarbituric Acid, Phenacetin 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.
Hawaii Pharm
See all Hawaii Pharm products- Name
- Hawaii Pharm LLC
- Street Address
- 510 Sumner St. Ste. 613
- City
- Honolulu
- State
- HI
- ZipCode
- 96817
- Phone Number
- 888-854-2924
- Web Address
- www.hawaiipharm.com
Evening Primrose by Hawaii Pharm: Common Questions
Does Evening Primrose by Hawaii Pharm interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Can I take this if I'm pregnant or breastfeeding?
What are the most common side effects?
Does evening primrose actually work?
Is this safe to use long-term?
What is gamma linolenic acid (GLA)?
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
- Bamford, J. T., Gibson, R. W., and Renier, C. M. Atopic eczema unresponsive to evening primrose oil (linoleic and gamma- linolenic acids). J Am.Acad.Dermatol. 1985;13(6):959-965.
- Preece PE, Hanslip JI Gilbert L. Evening primrose oil (Efamol) for mastalgia. In: Horrobin DF. Clinical Uses of Essential Fatty Acids . Montreal, Quebec: Eden;1982.
- Parveen, S. Sarwar G. Ali M. Channa G. A. Danazol versus oil of evening primrose in the treatment of mastalgia. Pakistan Journal of Surgery. 2007;23(1):10-13.
- Belch JJF, Shaw B, O'Dowd A, et al. Evening primrose oil (Efamol) as a treatment for cold-induced vasospasm (Raynaud's phenomenon). Prog Lipid Res 1986;25:335-40.
- Johnson, M., Ostlund, S., Fransson, G., Kadesjo, B., and Gillberg, C. Omega-3/omega-6 fatty acids for attention deficit hyperactivity disorder: a randomized placebo-controlled trial in children and adolescents. J.Atten.Disord. 2009;12(5):394-401. PubMed
- Farzaneh F, Fatehi S, Sohrabi MR, Alizadeh K. The effect of oral evening primrose oil on menopausal hot flashes: a randomized clinical trial. Arch Gynecol Obstet 2013;288(5):1075-9. PubMed
- Puri BK. The safety of evening primrose oil in epilepsy. Prostaglandins Leukotrienes Essential Fatty Acids 2007;77:101-3. PubMed
- Jalloh MA, Gregory PJ, Hein D, et al. Dietary supplement interactions with antiretrovirals: a systematic review. Int J STD AIDS. 2017 Jan;28(1):4-15. PubMed
- Osman M, Badawi E. Evening primrose oil reducing serum lithium concentration. Ther Adv Psychopharmacol. 2016 Oct;6(5):343-44. PubMed
- Kalati M, Kashanian M, Jahdi F, Naseri M, Haghani H, SHeikhansari N. Evening primrose oil and labour, is it effective? A randomized clinical trial. J Obstet Gynaecol. 2018 Feb 9:1-5.
- Sharif SN, Darsareh F. Impact of evening primrose oil consumption on psychological symptoms of postmenopausal women: a randomized double-blinded placebo-controlled clinical trial. Menopause. 2020;27(2):194-198. PubMed
- Shahraki AD, Mirhoseini S, Movahedi M, Hajihashemy M, Haghollahi F. Comparative Study of the Effect of Vaginal use of Primrose Oil with Misoprostol on Cervical Preparation of Prim Gravid Women: A Double-blind Clinical Trial. Adv Biomed Res 2023;12:78. PubMed
- Shahinfar S, Abedi P, Jahanfar S, Khajehpoor M, Chashmyazdan M. The effect of evening primrose oil on cervical ripening and birth outcomes: A systematic review and meta-analysis. Heliyon 2023;9(2):e13414. PubMed
- Mahmoodinasab M, Loripoor M, Vazirinejad R, Aminzadeh F. Effect of misoprostol with and without evening primrose (Oenothera biennis) on induction of missed abortion. Avicenna J Phytomed 2023;13(5):454-462.
- Hashemi H, Hasanpoor-Azghady SB, Farahani M, Amiri-Farahani L. Comparison of the effect of vaginal misoprostol and evening primrose oil capsule with misoprostol alone on the consequences of abortion in women with intrauterine fetal death: a randomized cli
- Ariana S, Amjadi N, Kazemi SN, Ahmadli Z. The Use of Evening Primrose Oil for Cervical Ripening in Low-Risk Women with Term Pregnancy: A Randomized Double-Blinded Controlled Trial. Complement Med Res 2024;31(3):215-221. PubMed
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