Effect of oral gamolenic acid from evening primrose oil on menopausal flushing

Abstract

Objective-To evaluate the efficacy of gamolenic acid provided by evening primrose oil in treating hot flushes and sweating associated with the menopause.Design-Randomised, double blind, placebo controlled study.Setting-District general hospital and teaching hospital.Subjects-56 menopausal women suffering hot flushes at least three times a day.Intervention-Four capsules twice a day of 500 mg evening primrose oil with 10 mg natural vitamin E or 500 mg liquid paraffin for six months.Main outcome measures-Change in the number ofhot flushes or sweating episodes a month.Results-56 diaries were analysed, 28 from women taking gamolenic acid and 28 from those taking placebo. Only 18 women given gamolenic acid and 17 given placebo completed the trial. The mean (SE) improvement in the number of flushes in the last available treatment cycle compared with the control cycle was 19 (0 4) (P < 0.001) for daytime flushes and 0 7 (0'3) (P<0'05) for night time flushes in women taking placebo; the corresponding values for women taking gamolenic acid were 0.5 (0.4) and 0 5 (0.3). In women taking gamolenic acid the only significant improvement was a reduction in the maximum number ofnight time flushes (1.4 (0 6); P< 005).Conclusion-Gamolenic acid offers no benefit over placebo in treating menopausal flushing.

The use of complementary and alternative medications by menopausal women in South East Queensland

“…In relation to menopausal symptoms such as hot flushes, studies have been undertaken on the clinical effectiveness of phytoestrogens (Albertazzi et al, 1998;Dalais et al, 1998;Drapier Faure, Chantre, & Mares, 2002;van de Weijer & Barentsen, 2002) and herbal therapies such as Chinese herbs (Davis et al, 2001), dong quai (Hirata et al, 1997), and evening primrose oil (Chenoy et al, 1994). The effect of nutritional supplements such as calcium on postmenopausal bone loss has also been explored (Aloia et al, 1994;Dawson-Hughes et al, 1990;Reid et al, 1993).…”

Menopause: a review of botanical dietary supplements

“…Our search identified 1 clinical trial evaluating the efficacy of evening primrose oil for the relief of menopausal symptoms (Table 3). 30 …”

“…The study by Chenoy and colleagues 30 randomized 56 women reporting Ͼ3 hot flashes per day to 2,000 mg evening primrose oil plus 20 mg vitamin E or placebo twice daily for 24 weeks. The investigators did not find any significant benefit for evening primrose oil over placebo in relieving the vasomotor symptoms of menopause.…”

Contemporary alternatives to plant estrogens for menopause

“…[74] The only RCT of evening primrose for menopausal symptoms found no differences in the reduction of hot flashes between the placebo and evening primrose groups. [62] …”

“…There is also very little data available on the efficacy and safety of many of these compounds, either used alone or in combination with other herbs. Table 2 [58][59][60][61][62][63][64][65][66][67][68][69] summarizes the available data on the clinical trials that have been conducted on these botanicals for menopausal women in specific. Trials conducted on non-menopausal populations are discussed in the text.…”