SNRI may be as effective as estrogen for hot flashes

A small study led by investigators from Brigham and Women’s Hospital suggests that the serotonin-norepinephrine reuptake inhibitor (SNRI) venlafaxine hydrochloride may be as effective as low-dose estradiol for relief of hot flashes. 

Venlafaxine is an antidepressant widely used as nonhormonal treatment of hot flashes but the new research may be the first clinical trial to simultaneously evaluate it and estradiol for that indication.

Published in JAMA Internal Medicine, the trial enrolled 339 perimenopausal and postmenopausal women from the community who had at least two bothersome hot flashes per day (mean, 8.1 per day). Randomization was to double-blind treatment with low-dose oral 17 β-estradiol (0.5 mg/d)(n=97), low-dose venlafaxine hydrochloride extended release (75 md/d)(n=96) or placebo (n=146) for 8 weeks.

Mean daily frequency of vasomotor symptoms after 8 weeks of treatment was the primary outcome, with vasomotor symptom severity, bother, and interference with daily life as secondary outcomes. The investigators compared change in vasomotor symptom frequency between each active intervention and placebo and between the two active treatments.

In the estradiol group, the mean frequency of vasomotor symptom frequency at week 8 decreased by 52.9%, to 3.9 (95% CI, 2.9-4.9) per day, compared with a 47.6% reduction to 4.4 per day (95% CI, 3.5-5.3) in the SNRI group and a 28.6% reduction to 5.5 per day (95% CI, 4.7-6.3) in the placebo group. Estradiol reduced the frequency of symptoms by 2.3 more per day than placebo (P<.001) compared with a reduction in frequency of 1.8 more per day for the SNRI than placebo (P=.005).

Although low-dose estradiol may be slightly superior to venlafaxine, the authors concluded that the difference between the hormonal and nonhormonal treatments for hot flashes was small and “of uncertain clinical relevance.”

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