Letter to the Editor

Lessons Learned from the Women's Health Initiative Study

Authors: Nasser Mikhail, MD, MSc

Abstract

I read with great interest the views of the Editor1 and those of different specialists regarding the results of Women’s Health Initiative (WHI) study,2 which showed an overall
harm of using postmenopausal hormonal replacement therapy (HRT). I would like to comment on the implications of the previous study on the management of hot flushes, an important issue that was not addressed sufficiently by the six experts. Hot flushes occur in
approximately 60% of women in the early postmenopausal period.3 Their prevalence then declines gradually, and hot flushes resolve in most women within 4 or 5 years.4 However, approximately 9% of women are still symptomatic at age 72 years.3 Hot flushes frequently
interfere with quality of life and sometimes can be disabling. Both estrogen5 and progesterone6 are highly effective in reducing the severity or eliminating hot flushes. It is not surprising therefore that the commonest indication of HRT is the control of postmenopausal vasomotor symptoms. After the release of the disturbing results of the WHI study,2 the main concern among postmenopausal women is to find nonhormonal
alternatives for the treatment of climacteric symptoms. It should be emphasized that in all studies that evaluated the effectiveness of various drugs on the severity of hot flushes, there was a substantial placebo effect ranging from 20 to 50%. Accordingly, the validity of results obtained from non-placebo-controlled trials is questionable. The two main agents that proved some efficacy in relieving hot flushes over placebo are clonidine and the selective serotonin reuptake inhibitors (SSRI). Clonidine has been used for that purpose since the early 1970s.7 One hypothesis related to the pathogenesis of hot flushes is the hyperactivity of the sympathetic nervous system. 8 Thus, the reduction of  sympathetic hyperactivity by clonidine, an 2-adrenergic agonist, is associated with amelioration of hot flushes. Another abnormality described in women with vasomotor
symptoms is the lowering of the threshold of core body temperature for sweating.
8 Both estrogen8 and clonidine9 have been shown to increase the sweating
threshold in women with hot flushes.

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References

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