Nonhormonal therapies for menopausal hot flashes: systematic review and meta-analysis

Concern regarding the adverse effects of estrogen and other hormones for treating menopausal symptoms has led to demand for other options; however, the efficacy and adverse effects of nonhormonal therapies are unclear.

To assess the efficacy and adverse effects of nonhormonal therapies for menopausal hot flashes by reviewing published randomized controlled trials.

MEDLINE (1966-October 2005), PsycINFO (1974-October 2005), and the Cochrane Controlled Clinical Trials Register Database (1966-October 2005) were searched for relevant trials that provided data on treatment of menopausal hot flashes using 1 or more nonhormonal therapies.

All English-language, published, randomized, double-blind, placebo-controlled trials of oral nonhormonal therapies for treating hot flashes in menopausal women measuring and reporting hot flash frequency or severity outcomes.

Trials were identified, subjected to inclusion and exclusion criteria, and reviewed. Data on participants, interventions, and outcomes were extracted and trials were rated for quality based on established criteria. A meta-analysis was conducted for therapies with sufficient trials reporting hot flash frequency outcomes.

From 4249 abstracts, 43 trials met inclusion criteria, including 10 trials of antidepressants, 10 trials of clonidine, 6 trials of other prescribed medications, and 17 trials of isoflavone extracts. The number of daily hot flashes decreased compared with placebo in meta-analyses of 7 comparisons of selective serotonin reuptake inhibitors (SSRIs) or serotonin norepinephrine reuptake inhibitors (SNRIs) (mean difference, -1.13; 95% confidence interval [CI], -1.70 to -0.57), 4 trials of clonidine (-0.95; 95% CI, -1.44 to -0.47), and 2 trials of gabapentin (-2.05; 95% CI, -2.80 to -1.30). Frequency was not reduced in meta-analysis of trials of red clover isoflavone extracts and results were mixed for soy isoflavone extracts. Evidence of the efficacy of other therapies is limited due to the small number of trials and their deficiencies. Trials do not compare different therapies head-to-head and relative efficacy cannot be determined.

The SSRIs or SNRIs, clonidine, and gabapentin trials provide evidence for efficacy; however, effects are less than for estrogen, few trials have been published and most have methodological deficiencies, generalizability is limited, and adverse effects and cost may restrict use for many women. These therapies may be most useful for highly symptomatic women who cannot take estrogen but are not optimal choices for most women.