Usage
Evening primrose oil is primarily used as a dietary supplement for various conditions, although scientific evidence supporting its efficacy is limited. It is most commonly used for eczema, premenstrual syndrome (PMS), rheumatoid arthritis, diabetic neuropathy, and menopausal symptoms like hot flashes. It is also sometimes used for inducing labor, although this is not a medically recommended use.
It is categorized as a herbal supplement or a complementary medicine. More specifically, it is a source of omega-6 essential fatty acids.
Its proposed mechanism of action is based on its gamma-linolenic acid (GLA) content. GLA is converted into prostaglandins, hormone-like substances that have anti-inflammatory effects and may play a role in various physiological processes.
Alternate Names
- King’s cureall
- Night willow herb
- Oenothera biennis
- Scabish
- Sun drop
- Fever plant
- Stella di sera
Some brand names include: Efamol and Blackmores.
How It Works
Pharmacodynamics: Evening primrose oil’s primary active component, GLA, is metabolized to prostaglandin E1, which possesses anti-inflammatory properties. It may also affect hormone balance and cell membrane function. The exact mechanisms underlying its purported benefits are not fully understood.
Pharmacokinetics: Evening primrose oil is taken orally or applied vaginally as a suppository. Absorption, metabolism, and elimination data in humans are limited. GLA is metabolized in the liver and eliminated through the kidneys. Specific information on receptor binding, enzyme inhibition, or neurotransmitter modulation is scarce.
Dosage
Standard Dosage
Adults:
- General health and wellbeing: 2 capsules (500mg each) per day.
- Skin health and anti-inflammatory support: 2 capsules (500mg each) twice a day.
- Maximum dose: Up to 8 grams per day (based on available source)
- Administration: Oral capsules, typically taken with food.
Children:
Dosing for children varies by age and health conditions. Generally, a lower dose than for adults is recommended. Children under 12 years of age should not take it unless advised by a healthcare professional. Children aged 5-12: 1 to 3 capsules (500mg each) per day. Always consult a pediatrician before administering evening primrose oil to children.
Special Cases:
Dosing adjustments may be needed for elderly patients and those with renal or hepatic impairment, but specific guidelines are lacking. Consult a healthcare professional for individualized dosing recommendations.
Clinical Use Cases
Evening primrose oil has no established role in clinical settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations.
Dosage Adjustments
Specific dosage adjustments based on patient-specific factors are not well-defined due to limited clinical research.
Side Effects
Common Side Effects
- Headache
- Upset stomach
- Nausea
- Diarrhea
- Dizziness
Rare but Serious Side Effects
Long-Term Effects
There is no information about long-term effects in the provided sources.
Adverse Drug Reactions (ADR)
There is no information about ADRs in the provided sources.
Contraindications
- Bleeding disorders
- Epilepsy or seizure disorders
- Schizophrenia
- Late stages of pregnancy
- Use with caution in individuals with diabetes, alcohol dependence, or liver disease
Drug Interactions
- Anticoagulant/Antiplatelet drugs: Increased bleeding risk.
- Phenothiazines: Increased seizure risk.
- Lopinavir/Ritonavir: Increased lopinavir/ritonavir levels and side effects.
- Lithium: Decreased lithium levels.
- CYP3A4 substrates: Potential interaction.
Pregnancy and Breastfeeding
Evening primrose oil is possibly safe during early pregnancy but may delay labor if taken during the last weeks of pregnancy. It is possibly safe during breastfeeding, but caution is advised. Consult with a healthcare professional before use during pregnancy or lactation.
Drug Profile Summary
- Mechanism of Action: GLA is metabolized to prostaglandin E1, which has anti-inflammatory properties.
- Side Effects: Headache, upset stomach, nausea, diarrhea, dizziness. Rare: bleeding, bruising.
- Contraindications: Bleeding disorders, epilepsy, schizophrenia, late pregnancy.
- Drug Interactions: Anticoagulants, phenothiazines, lopinavir/ritonavir, lithium.
- Pregnancy & Breastfeeding: Possibly safe in early pregnancy, avoid in late pregnancy. Possibly safe during breastfeeding, but caution is advised.
- Dosage: Adults: 2-8 grams/day. Children: Lower doses, consult pediatrician. Special adjustments based on clinical data are not well-defined.
- Monitoring Parameters: None specifically established.
Popular Combinations
No specific established beneficial or synergistic combinations.
Precautions
- General Precautions: Pre-screening for allergies, bleeding disorders, and interactions with existing medications is advised.
- Specific Populations: Consult with a healthcare professional for use during pregnancy/lactation, in children, and in the elderly.
- Lifestyle Considerations: Avoid alcohol and other potentially interacting substances. Driving restrictions are not typically necessary.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Evening Primrose Oil?
A: Dosage varies based on the intended use. Adults: 2 to 8 grams per day, taken orally with food. Children: Lower doses, consult a pediatrician. For specific conditions, consult a healthcare professional.
Q2: Is evening primrose oil safe during pregnancy?
A: Possibly safe during early pregnancy, but should be avoided in the final weeks as it may delay labor.
Q3: Can I take evening primrose oil while breastfeeding?
A: Possibly safe during breastfeeding. However, it’s best to consult a healthcare provider first.
Q4: What are the common side effects of evening primrose oil?
A: Headache, upset stomach, nausea, diarrhea, and dizziness are common side effects.
Q5: Are there any serious side effects to be aware of?
A: In rare cases, evening primrose oil may cause bleeding or bruising.
Q6: Does evening primrose oil interact with any medications?
A: Yes, it can interact with anticoagulants/antiplatelet drugs, phenothiazines, lopinavir/ritonavir, and lithium. It may also interact with CYP3A4 substrates. Always discuss existing medication use with a doctor or pharmacist.
Q7: What is the mechanism of action of evening primrose oil?
A: GLA is metabolized into prostaglandin E1, which has anti-inflammatory properties. The exact mechanisms of action are not entirely clear.
Q8: Can evening primrose oil be used to induce labor?
A: While sometimes used for this purpose, it’s not medically recommended and may increase the risk of complications. Consult with an obstetrician before using it for labor induction.
Q9: Are there any contraindications to using evening primrose oil?
A: Yes, contraindications include bleeding disorders, epilepsy or seizure disorders, schizophrenia, and late-stage pregnancy. Caution is advised in patients with diabetes, alcohol dependence, or liver disease. Always consult with a healthcare provider if considering evening primrose oil.
