Despite the avid interest in finding nonhormonal therapies for menopausal hot flashes, most alternative treatments have demonstrated only limited efficacy, and their safety remains in question, according to a systematic review of the literature.
Dr. Heidi D. Nelson and her associates at Oregon Health and Science University, Portland, identified all randomized, placebo-controlled trials of nonhormonal treatments for hot flashes in the English literature and compared the efficacy and adverse effects of agents other than estrogens, progestins, progesterone, or androgens.
From an initial screening of 4,249 abstracts, they narrowed their focus to 43 trials with adequate study designs. However, even these trials were often flawed by high dropout rates, small study samples, short follow-up periods, and methodologic failings, they noted (JAMA 2006;295:2057–71).
The selected studies included 10 that assessed antidepressants, 10 assessing clonidine, 6 assessing other prescription drugs, and 17 assessing isoflavone extracts.
Eleven of the trials included women with breast cancer, many of whom were receiving tamoxifen. This is a population in whom hot flashes are particularly common and for whom estrogen therapy is contraindicated, the researchers said.
A metaanalysis was conducted using 24 of the 43 studies.
Overall, there was some evidence that selective serotonin reuptake inhibitors, serotonin norepinephrine reuptake inhibitors, clonidine, and gabapentin reduce the severity and frequency of hot flashes. However, none of these agents approached the effectiveness of hormone therapy.
“Although these therapies may be most useful for highly symptomatic women who cannot take estrogen, they are not optimal choices for most women.” Their safety as treatments for hot flashes has not been adequately studied, and the adverse effects they cause as well as their cost will make their use prohibitive for many women, Dr. Nelson and her associates said.
The evidence for soy isoflavone extracts was contradictory, “even among the largest and highest quality trials,” they noted. No evidence supported the efficacy of red clover isoflavone extracts.