Evening Primrose (Oenothera biennis): Benefits, Dosage, Safety & Evidence

Qu'est-ce qu'une interaction plante-médicament ?

Une interaction plante-médicament se produit lorsqu'une plante ou un complément modifie l'action d'un médicament dans votre organisme — en le rendant plus puissant, moins efficace, ou plus susceptible de provoquer des effets nocifs. Les plantes contiennent des composés actifs qui peuvent accélérer ou ralentir les enzymes et transporteurs utilisés pour métaboliser les médicaments.

Pourquoi c'est important

Millepertuis peut rendre la contraception, les antidépresseurs et les anticoagulants moins efficaces.

Ail peut augmenter le risque de saignement avec la warfarine et autres anticoagulants (aussi ginkgo, gingembre et curcuma).

Kava peut amplifier la sédation avec les médicaments contre l'anxiété ou le sommeil (aussi la valériane).

Le risque est plus élevé chez les personnes âgées, ceux qui prennent plusieurs médicaments et les personnes atteintes de maladies chroniques.

Indiquez toujours à votre médecin et à votre pharmacien toutes les plantes et compléments que vous prenez — et vérifiez ci-dessous avant toute association.

Interactions Médicamenteuses Connues (2)

1 Sévère1 Modéré

Médicament	Sévérité	Description
Warfarin (Coumadin)	Modéré	L'huile de primevère du soir pourrait avoir des propriétés anticoagulantes légères qui s'ajoutent à l'effet de la warfarine.
Phenothiazines (Chlorpromazine)	Sévère	L'huile de priming nocturne peut abaisser le seuil de crise, augmentant le risque de crises chez les patients prenant des phenothiazines.

Cette liste reflète un sous-ensemble sélectionné d'interactions documentées et n'est pas exhaustive. L'absence d'un médicament ici ne prouve pas qu'il est sans danger à combiner. Confirmez toujours auprès d'un pharmacien ou d'un professionnel de santé.

Questions fréquentes

How does evening primrose oil work in the body?

Evening primrose oil works primarily through its high gamma-linolenic acid (GLA) content, an omega-6 fatty acid. GLA is converted in the body to prostaglandin E1, which has anti-inflammatory and hormone-regulating properties. This conversion occurs via the delta-6 desaturase enzyme pathway, which can be impaired in certain health conditions. The resulting prostaglandins help modulate inflammation, support skin barrier function, and regulate hormonal responses. Evidence level: B for mechanism understanding.

Does evening primrose oil interact with any medications?

Yes, evening primrose oil has clinically significant drug interactions. It may increase bleeding risk when combined with anticoagulants (warfarin, heparin), antiplatelet agents (aspirin, clopidogrel), or NSAIDs. It should be avoided with phenothiazine medications used for schizophrenia, as this combination may increase seizure risk. Patients on anticonvulsant medications should use caution. Due to potential bleeding effects, evening primrose oil should be discontinued at least two weeks before scheduled surgery. Evidence level: C for interactions.

What is the recommended dosage for evening primrose oil?

The standard adult dosage of evening primrose oil is 2-8 grams daily, taken in divided doses with meals to enhance absorption. This provides approximately 240-960mg of gamma-linolenic acid (GLA) per day. For cyclic breast pain (mastalgia), clinical studies have typically used 3-4 grams daily. For premenstrual symptoms, 2-4 grams daily is common. Therapeutic effects may require 3-4 months of consistent use. Start with lower doses to assess individual tolerance. Evidence level: B for dosing recommendations.

Is evening primrose oil safe to take during pregnancy?

Evening primrose oil is considered unsafe during pregnancy and is not recommended. Although some traditional use exists for cervical ripening near term, there is insufficient evidence for safety. The oil may stimulate uterine contractions or increase bleeding risk during delivery. Pregnant women should avoid evening primrose oil throughout all trimesters. Women who are breastfeeding should consult a qualified healthcare provider before use, as safety data during lactation is limited. Evidence level: D for pregnancy safety.

Can evening primrose oil help with breast pain and PMS symptoms?

Evening primrose oil has been extensively studied for cyclic breast pain (mastalgia) and premenstrual symptoms. The GLA content supports prostaglandin synthesis, which may reduce breast tenderness and swelling. Evidence is stronger for breast pain, with Commission E approval for this indication, while PMS results remain mixed across clinical trials. Benefits typically require 3-4 months of consistent daily use. Individual response varies considerably, and not all users experience symptom improvement. Evidence level: B for breast pain, C for PMS.

Fiche d'information compilée à partir de PubMed

Cette fiche a été compilée à partir de résumés PubMed (NIH) avec l'assistance d'une IA. Chaque affirmation factuelle est citée par un article PubMed réel (voir la liste des sources). Elle n'a pas encore été révisée par un humain — confirmez auprès d'un professionnel de santé avant utilisation.

Compilé à partir de 29 articles PubMed · modèle : gemma4:31b

Résumé

Evening primrose (Oenothera biennis) is a plant source of omega-6 essential fatty acids used primarily for inflammatory conditions and women's health [PMID:20000302, PMID:37614101].

Contexte

Evening primrose (Oenothera biennis) is a plant in the Onagraceae family [PMID:30110920]. It is commonly used as an alternative therapy and is a rich source of omega-6 essential fatty acids [PMID:20000302].

Usages traditionnels

It is believed in traditional medicine to facilitate labor [PMID:24535321].

Composés actifs

The seeds contain a fixed oil (EPO) rich in linoleic acid (60%-80% or 70-74%) and gamma-linolenic acid (GLA) (8%-14% or 8-10%) [PMID:30110920, PMID:31497576, PMID:37614101]. Other components include aliphatic alcohols, sterols, polyphenols, triterpenes, phenolic acids, tocopherols, and phytosterols [PMID:30110920, PMID:37614101].

Preuves cliniques

Preuve AMastalgia (Breast Pain)

Mixed results: some sources suggest symptoms may be attenuated [PMID:12391713], while a meta-analysis of 13 trials found no difference compared to placebo [PMID:34200727] and other reviews suggest it is likely ineffective [PMID:20000302].

Preuve AMenopausal Hot Flashes

A systematic review found that severity of hot flashes was lower when EPO was administered for less than 6 months compared to placebo, though no significant difference was found in frequency and duration [PMID:39829189].

Preuve AAtopic Dermatitis/Eczema

Current evidence suggests oral EPO does not provide clinically significant improvement [PMID:20000302].

Preuve CPremenstrual Syndrome (PMS)

Likely ineffective for the treatment of premenstrual syndrome [PMID:20000302].

Preuve BCervical Ripening/Parturition

Vaginal EPO (2000 mg) showed significantly greater cervical dilation (larger Hegar dilator size) compared to vaginal misoprostol (200 μg) before gynecological surgery [PMID:37102338]. In missed abortion, addition of 2000 mg vaginal EPO to misoprostol showed significant differences in full abortion and cervical dilatation [PMID:38089421].

Preuve A

Sécurité et effets indésirables

Evening primrose oil is 'generally recognized as safe' (GRAS) as a food by the U.S. FDA [PMID:30000954]. Reported adverse events in peripartum persons were generally mild [PMID:36548328].

Grossesse et allaitement

Some suggest intake throughout pregnancy to prevent preterm delivery and promote easier birth [PMID:15124319], but other reviews state very few scientific data support the facilitation of labor and note associations with severe adverse events [PMID:24535321]. In nursing mothers, EPO increases breastmilk content of linoleic acid and total GLA without causing adverse reactions in breastfed infants [PMID:30000954].

Synthèse des preuves

The evidence is mixed and often contradictory. While some systematic reviews and meta-analyses suggest ineffectiveness for mastalgia and atopic dermatitis, specific clinical trials show efficacy for cervical ripening. Evidence for menopausal symptoms and rheumatoid arthritis remains inconsistent.

Sources PubMed

1.PMID: 34946512 (2021) — Herbal Products Used in Menopause and for Gynecological Disorders. · Molecules (Basel, Switzerland)
2.PMID: 30000954 (2006) — A review of effective herbal medicines in controlling menopausal symptoms. · Electronic physician
3.PMID: 20000302 (2009) — Evening primrose oil. · American family physician
4.PMID: 34957578 (2022) — An updated review on efficacy and benefits of sweet almond, evening primrose and jojoba oils in skin care applications. · International journal of cosmetic science
5.PMID: 21477394 (2011) — Breast pain. · BMJ clinical evidence
6.

Evening Primrose

Sources et citations

Calculer une dose sûre de Evening Primrose

Red Clover

Black Cohosh

Vitex Negundo

⚠️ Non recommandé pendant la grossesse ou l'allaitement

2 interactions médicamenteuses connues — Certaines peuvent être graves

Contre-indications

Effets secondaires possibles

Qu'est-ce qu'une interaction plante-médicament ?

Interactions Médicamenteuses Connues (2)

Questions fréquentes

Résumé

Contexte

Usages traditionnels

Composés actifs

Preuves cliniques

Sécurité et effets indésirables

Grossesse et allaitement

Synthèse des preuves

Sources PubMed

Sources gouvernementales

Evening Primrose

Sources et citations

Calculer une dose sûre de Evening Primrose

Plantes associées

Red Clover

Black Cohosh

Vitex Negundo

⚠️ Non recommandé pendant la grossesse ou l'allaitement

2 interactions médicamenteuses connues — Certaines peuvent être graves

Contre-indications

Effets secondaires possibles

Qu'est-ce qu'une interaction plante-médicament ?

Interactions Médicamenteuses Connues (2)

Questions fréquentes

Résumé

Contexte

Usages traditionnels

Composés actifs

Preuves cliniques

Sécurité et effets indésirables

Grossesse et allaitement

Synthèse des preuves

Sources PubMed

Sources gouvernementales