Herb Of The Month - Evening Primrose

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HA! I bet you forgot there even was an herb of the month! ;-p

 

Have a great weekend folks! Enjoy the last days of April, for May is

just around the corner!

 

I've got my Maypole ready, do you?

 

*Smile*

Chris (list mom)

 

Jasmine & Orange Blossom Floral Waxes

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Supplements for Menopause. Information from Today’s Dietitian, November

2005.

 

EVENING PRIMROSE OIL: also known as EPO, fever plant, gamma linolenic

acid (GLA), and linoleic acid. Well-known for treating PMS and

menopausal symptoms.

 

§ Generally well-tolerated

 

§ Many small studies have not demonstrated benefit, but researchers

suggest this may be due to the short length of studies that have been

done. It may be necessary to take EPO for 4-6 months to see full

benefit.

 

§ Typical dosage is 2-4 grams daily

 

§ Due to few harmful effects and limited studies, this supplement can be

recommended

 

§ Do not take if pregnant

Herbs of Special Interest to Women

 

Mary L. Hardy

J Am Pharm Assoc 40(2):234-242, 2000. © 2000 American Pharmaceutical

Association

Evening Primrose Oil

 

Evening primrose, Oenothera biennis L., is a North American wildflower

that has escaped cultivation and is now widely distributed infields or

along roadsides.[2] Named so because its flower opens in the evening,

the evening primrose is in fact not a true primrose. Traditionally, the

plant was valued as a food, and its roots and seeds were

eaten.[3]Medicinal use of evening primrose has a long history among

Native Americans, and use of the plant was transferred to Europe by

colonial settlers.

 

Modern interest has centered on the oil expressed from the plant's small

dark seeds. The seeds produce a fixed oil rich in essential fatty

acids:approximately 65% linoleic acid and 8% to 10% gamma-linolenic

acid.[4,5] These constituents are critical precursors in the manufacture

of prostaglandin E1, one of the anti-inflammatory prostaglandins.[6]

 

A number of studies have evaluated the efficacy of evening primrose oil

(EPO) in the treatment of premenstrual syndrome (PMS). The rationale for

this use is that women with PMS have an abnormal profile of essential

fatty acids, which may be normalized by supplementation with EPO.[6-9]

Brush et al.[7] reported that women with PMS have high levels of

nonessential fatty acids but low levels of all metabolites of linoleic

acid, including arachidonic acid. These investigators reported that

gamma-linolenic acid levels were below detectable levels in PMS

patients, and postulated that PMS is associated with a defect in the

conversion of linoleic acid to gamma-linolenic acid. Abnormal levels of

essential fatty acids also have been observed in women with benign

breast disorders.[8]

 

Clinical Studies

In an open label study, Brush[10] evaluated the efficacy of EPO for PMS

symptoms in 68 women. The women received EPO (1 to 2 grams per day) from

3 days before the usual onset of their PMS symptoms until the onset of

menses. Based on a patient self-report scale, 41 women (61%) had

complete relief of their symptoms and 16 (23%) had partial relief after

at least 3 months of treatment.The most pronounced symptom relief was

for mastalgia (breast pain).

Many additional trials, such as those conducted by Larson et al.[11] and

Ylikorkala et al.,[12] have reported modest benefits of EPO for PMS

symptoms. However, these favorable effects were not replicated in a

double-blind,placebo-controlled crossover trial of 38 women with

PMS.[13] This study, which used a daily EPO dose of eight capsules

(presumably 4 grams), failed to demonstrate statistically or clinically

significant results.[13]Furthermore, an attempted meta-analysis of the

effects of EPO on general PMS symptoms also did not demonstrate

conclusive efficacy.[14] The majority of trials cited suffered from

methodological flaws that made meta-analysis difficult, such as an open

study design with no placebo control and a placebo-controlled,

parallel-group study without a defined randomization scheme.[11,15,16]

 

Although clinical studies have not shown a clear benefit of EPO for PMS,

more pronounced improvement has been demonstrated for relief of

mastalgia. A double-blind, placebo-controlled study compared the effects

of danazol, bromocriptine, EPO, progestins, and placebo in 291 women

with mastalgia.[17] The experimental agents were tried sequentially, and

the patients subjectively rated their relief by recording their

assessment of pain on a visual analogue scale supplemented by a pain

diary. EPO (3 grams per day) was effective forcyclical mastalgia in 45%

of patients, with a relapse rate of 21% after the first course of

treatment. Effectiveness was defined as either a Grade I response (no

residual pain) or a Grade II response (some residual pain that the

patient described as easily bearable).

 

Only 2% of the EPO-treated patients reported side effects (mild bloating

with vague nausea).[17] Compared with danazol, EPO was less effective

(70% versus 45%), but had fewer side effects (22% versus 2%). EPO had

similar efficacy to bromocriptine(47% versus 45%), again with fewer side

effects (2% versus 33%). Effectiveness rates for all therapies were

lower in patients with noncyclical mastalgia, with danazol showing a 31%

response rate; EPO, 27%; bromocriptine, 20%; and progesterone, 9%.

 

A much lower response rate was recently reported in a clinical survey

conducted at a hospital-based mastalgia clinic in Australia, which

recorded observations on 170 patients for 3 years.[18] Response rates of

only 26% were reported for mastalgia patients receiving EPO, while

low-dose danazol achieved an effect in 67% of the patients.

 

Despite the mixed results of these studies, many clinicians recommend

EPO as a first-line treatment for cyclic mastalgia.[8,19-25] For

example, in a recent survey 13% to 30% of British surgeons recommended

EPO for this use.[24] Patients with severe PMS symptoms, in another

recent survey,[26] also rated EPO as one of the most effective

treatments they had used.

 

Considerations for Patient Use

Given its good safety profile, EPO can reasonably be tried for PMS at a

dose of 2 to 4 grams (standardized to 9% gamma-linolenic

acid),especially if mastalgia is present. EPO also may confer benefit

for other symptoms associated with PMS, such as irritable bowel

syndrome.[27] A critical analysis is under way to further examine

questions of efficacy at the Cochrane Collaboration, which is producing

a compendium of systematic evidence-based reviews.[28]

Given its reputed usefulness in PMS, EPO has also been tried for

management of menopausal symptoms, but its use for this indication has

much less data to recommend it. A double-blind, placebo-controlled trial

of 56 menopausal women failed to demonstrate a statistically significant

effect of EPO (2 grams/day) on hot flushes.[29] Although a small,

statistically significant improvement in the number of nighttime

flushing episodes (P < .05) was recorded, the study did not report

whether the patients considered this improvement to be significant.