Evening Primrose Herb 450 mg Ingredients & Drug Interactions
by TerraVita Premium Collection
What is this page for?
First and foremost: checking Evening Primrose Herb 450 mg 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 Herb 450 mg is a dietary supplement by TerraVita Premium Collection 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. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.
Check Your Meds Against Evening Primrose Herb 450 mg by TerraVita Premium Collection
Ask about any prescription or over-the-counter medication and we check it for interactions with Evening Primrose Herb 450 mg by TerraVita Premium Collection — 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 Herb 450 mg by TerraVita Premium Collection
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 (450 mg per capsule). Evening primrose oil is extracted from the seeds of the evening primrose plant and is used in herbal supplements for various purposes.
The capsule itself is made from gelatin and water — these are inactive ingredients that hold the formula together.
Does it work?
Couldn't assess
The evidence for evening primrose varies by intended use. For asthma, it's rated possibly ineffective.
For breast pain (mastalgia), it's likely ineffective. For abortion, acne, hysteroscopy preparation, and attention deficit-hyperactivity disorder (ADHD), the evidence is too limited to rate — we simply don't have enough reliable research to say whether it works or doesn't.
Talk with your pharmacist or doctor about what you're hoping to use it for; they can tell you whether the science supports it.
How safe is it?
Well-documented data
Evening primrose is generally well tolerated when used short-term by mouth, though quality evidence and long-term safety data are limited. The most common side effects are gastrointestinal: abdominal pain, bloating, diarrhea, indigestion, gas, nausea, and vomiting.
A small number of users have reported dizziness, headache, skin rash, or acne. There's a rare case report of seizures in a patient taking evening primrose with anesthesia, though other medications were involved so it's unclear if evening primrose was the cause.
During pregnancy and breastfeeding, evening primrose is rated possibly safe, though evidence is unclear and some concerns have been raised — talk with your doctor or pharmacist before using it if you're pregnant or nursing.
Meds to double-check
Moderate interaction found
Before taking this product, double-check with your pharmacist if you take blood thinners or antiplatelet drugs (warfarin, aspirin, clopidogrel — Moderate risk of bleeding), lithium (Moderate — levels may drop), phenothiazines like chlorpromazine (Moderate — seizure risk), lopinavir/ritonavir (Moderate — drug levels may rise), or other medications processed through the CYP2C9 liver enzyme (Minor — levels may climb slightly).
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 worth considering if you've researched it for a specific condition and your doctor agrees — but check your medications first, especially if you take blood thinners, lithium, antipsychotics, or HIV drugs. Most people tolerate it well short-term, though long-term safety isn't well established.
Run your exact medications through the tool on this page before you start.
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 Feb 21, 2023.
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 Herb 450 mg, straight from the product label.
| Brand | TerraVita Premium Collection |
|---|---|
| Barcode (UPC) | 064435113988 |
| Net contents | 100 Capsule(s) |
| Market status | On market |
| Date entered into DSLD | Feb 21, 2023 |
| DSLD ID | 286519 |
| Product type | Botanical |
| Supplement form | Capsule |
| Dietary claims / uses | All Other, Structure/Function |
| Intended target group(s) | Adult (18 - 50 Years) |
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 Herb 450 mg by TerraVita Premium Collection, sourced from the NIH Dietary Supplement Label Database.
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.
FDA Statement of Identity
A Dietary Supplement
Brand IP Statement(s)
Copyright 2004 TerraVita - Distributed by ZooScape LLC, All Rights Reserved.
Suggested/Recommended/Usage/Directions
Directions Take 1 capsule, 3 times daily, with meals.
General Statements
TerraVita is an exclusive line of premium natural products that use the finest, purest and most potent ingredients in the world. TerraVita's hallmarks are the highest possible standards of purity, potency, stability and freshness. All products are prepared with the greatest quality control, from raw materials through the entire manufacturing process, right up to the moment your product is sealed for freshness and shipped to you.
Please recycle!
FDA Disclaimer Statement
Statements not evaluated by FDA. Product not intended to diagnose, treat, cure, or prevent any disease.
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
Evening Primrose Herb 450 mg by TerraVita Premium Collection 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 Herb 450 mg by TerraVita Premium Collection
This is the 1 active ingredient this product is made of. Select it to open its full monograph.
Serving size1 Capsule(s) Dosage formCapsule Servings per container100 Amounts shown are per serving.
Evening Primrose
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 monograph & interactionsOther (inactive) ingredients: Gelatin, Water. These complete the product’s ingredient list but are not active constituents.
Evening Primrose Herb 450 mg by TerraVita Premium Collection Drug Interactions
HelloPharmacist Interaction Report
TerraVita Premium Collection Evening Primrose Herb 450 mg contains one active ingredient — evening primrose — which has documented interactions with several medication types.
The most serious concern is with blood thinners and antiplatelet drugs (like warfarin, aspirin, or clopidogrel): evening primrose contains a compound called gamma linolenic acid (GLA) that can thin your blood further and prolong bleeding time, raising your risk of bleeding. This is a Moderate severity interaction.
Read the full breakdown — every affected drug type, severity by severity
You'll also want to flag lithium (a mood stabilizer), phenothiazines (older antipsychotics used for schizophrenia or severe psychiatric conditions), and lopinavir/ritonavir (an HIV medication) — all Moderate severity. Lithium levels may drop, phenothiazines carry a theoretical risk of seizures when combined with evening primrose, and lopinavir levels may climb.
There's also a Minor interaction with drugs processed through CYP2C9 (a liver enzyme), which may accumulate slightly in your bloodstream. Altogether, these interactions span 230 individual medications.
Before you start evening primrose, run your exact medications — especially anything for bleeding, mood, seizures, or HIV — through the checker on this page. We can't check interactions for every possible drug, but this list covers the main known ones.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against Evening Primrose Herb 450 mg?
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 Herb 450 mg interact with 233 drugs. Click any drug to see the details.
1 of the 1 ingredient in Evening Primrose Herb 450 mg interact with drugs. Each result below shows which ingredient is responsible. Evening Primrose
AbciximabReoPro
How Abciximab interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Abciximab interactionAbrocitinibCibinqo
How Abrocitinib interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseCytochrome 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 + Abrocitinib interactionAcenocoumarolSintrom
How Acenocoumarol interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Acenocoumarol interactionAcepromazineAtravet
How Acepromazine interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimrosePhenothiazines Moderate
Interaction Summary
Theoretically, taking evening primrose oil with phenothiazines might increase the risk of convulsions.
Read the full Evening Primrose + Acepromazine interactionAcetaminophen, AspirinGemnisyn
How Acetaminophen, Aspirin interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Acetaminophen, Aspirin interactionAcetaminophen, Aspirin, CaffeineExcedrin, Excedrin Extra Strength, Excedrin Migraine
How Acetaminophen, Aspirin, Caffeine interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Acetaminophen, Aspirin, Caffeine interactionAcetaminophen, IbuprofenCombogesic
How Acetaminophen, Ibuprofen interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseCytochrome 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 + Acetaminophen, Ibuprofen interactionAcetylsalicylic AcidEntrophen
How Acetylsalicylic Acid interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Acetylsalicylic Acid interactionAlteplase, TpaActilyse, Activase
How Alteplase, Tpa interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Alteplase, Tpa interactionAluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium HydroxideAscriptin Codeine #2
How Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium Hydroxide interactionAluminum Hydroxide, Aspirin, Magnesium HydroxideAscriptin
How Aluminum Hydroxide, Aspirin, Magnesium Hydroxide interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Aluminum Hydroxide, Aspirin, Magnesium Hydroxide interactionAmitriptyline, PerphenazineEtrafon, Etrafon-A, Etrafon-Forte, Triavil
How Amitriptyline, Perphenazine interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseCytochrome 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 + Amitriptyline, Perphenazine interactionAnacaulase-bcdbNexoBrid
How Anacaulase-bcdb interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Anacaulase-bcdb interactionAnagrelideAgrylin
How Anagrelide interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Anagrelide interactionAnisindioneMiradon
How Anisindione interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Anisindione interactionAntithrombin IiiThrombate III
How Antithrombin Iii interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Antithrombin Iii interactionApixabanEliquis
How Apixaban interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Apixaban interactionArgatrobanArgatroban
How Argatroban interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Argatroban interactionAspirinAngettes 75, ASA, Asaphen, Aspirin, Caprin, Cartia +8 more
How Aspirin interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Aspirin interactionAspirin, Aluminum Hydroxide, Codeine Phosphate, Magnesium HydroxideAscriptin Codeine #3
How Aspirin, Aluminum Hydroxide, Codeine Phosphate, Magnesium Hydroxide interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Aspirin, Aluminum Hydroxide, Codeine Phosphate, Magnesium Hydroxide interactionAspirin, ButalbitalAxotal
How Aspirin, Butalbital interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Aspirin, Butalbital interactionAspirin, Butalbital, CaffeineFiorinal
How Aspirin, Butalbital, Caffeine interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Aspirin, Butalbital, Caffeine interactionAspirin, Butalbital, Caffeine, Codeine PhosphateFiorinal w/ Codeine
How Aspirin, Butalbital, Caffeine, Codeine Phosphate interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Aspirin, Butalbital, Caffeine, Codeine Phosphate interactionAspirin, Butalbital, Caffeine, PhenacetinMarnal
How Aspirin, Butalbital, Caffeine, Phenacetin interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Aspirin, Butalbital, Caffeine, Phenacetin interactionAspirin, CaffeineAnacin
How Aspirin, Caffeine interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Aspirin, Caffeine interactionAspirin, Caffeine, Codeine PhosphateAnacin w/ Codeine
How Aspirin, Caffeine, Codeine Phosphate interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Aspirin, Caffeine, Codeine Phosphate interactionAspirin, Caffeine, Dihydrocodeine BitartrateSynalgos DC
How Aspirin, Caffeine, Dihydrocodeine Bitartrate interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Aspirin, Caffeine, Dihydrocodeine Bitartrate interactionAspirin, Caffeine, Dover's PwdAcedoval, Dovacet
How Aspirin, Caffeine, Dover's Pwd interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Aspirin, Caffeine, Dover's Pwd interactionAspirin, Caffeine, HydrocodoneDamason-P
How Aspirin, Caffeine, Hydrocodone interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Aspirin, Caffeine, Hydrocodone interactionAspirin, Caffeine, Isobutylallylbarbituric Acid, PhenacetinLanorinal
How Aspirin, Caffeine, Isobutylallylbarbituric Acid, Phenacetin interacts with Evening Primrose Herb 450 mg — through 1 ingredient. Tap an ingredient for the detail:
Evening PrimroseAnticoagulant/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 + Aspirin, Caffeine, Isobutylallylbarbituric Acid, Phenacetin interactionEach ingredient & the kinds of drugs it affects
For each ingredient in Evening Primrose Herb 450 mg 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
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 Herb 450 mg, from the product label.
TerraVita Premium Collection
See all TerraVita Premium Collection products- Name
- TerraVita Fine Whole Herbs
- City
- Brampton
- State
- Ontario
Evening Primrose Herb 450 mg by TerraVita Premium Collection: Common Questions
Does Evening Primrose Herb 450 mg by TerraVita Premium Collection interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Does evening primrose actually work for anything?
What are the most common side effects?
Can I take this if I'm pregnant or breastfeeding?
How long is it safe to take evening primrose?
What exactly is evening primrose?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if Evening Primrose Herb 450 mg 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 Herb 450 mg’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 Herb 450 mg'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
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