Estrogen therapy is the gold standard treatment for hot flashes and night sweats, but some women are unable or unwilling to use it because of associated risks. The serotonin-norepinephrine reuptake inhibitor venlafaxine is used widely as a non-hormonal treatment. While clinical impression is that serotonin-norepinephrine reuptake inhibitors are less effective than estrogen, these medications have not been simultaneously evaluated in one clinical trial.
To determine the efficacy and tolerability of low-dose oral 17-beta-estradiol and low-dose venlafaxine XR in alleviating vasomotor symptoms.
Design and Participants
339 peri- and postmenopausal women with ≥2 bothersome vasomotor symptoms per day (mean 8.1, SD 5.3/day) were recruited from the community to MsFLASH (Menopause Strategies: Finding Lasting Answers for Symptoms and Health) clinical network sites November 2011—October 2012.
Participants were randomized to double-blinded treatment with low-dose oral 17-beta-estradiol 0.5-mg/day (n=97), low-dose venlafaxine XR 75-mg/day (n=96), or placebo (n=146) for 8 weeks.
Primary outcome was the mean daily frequency of vasomotor symptoms after 8 weeks of treatment. Secondary outcomes were vasomotor symptom severity, bother and interference. Intent-to-treat analyses compared change in vasomotor symptom frequency between each active intervention and placebo and between the two active treatments.
Compared to baseline, mean vasomotor symptom frequency at week 8 decreased by 53% with estradiol, 48% with venlafaxine, and 29% with placebo. Estradiol reduced the frequency of symptoms by 2.3 (95% CI 1.3–3.4) more per day than placebo (p<0.001), and venlafaxine by 1.8 (95% CI 0.8–2.7) more per day than placebo (p=0.005). Results were consistent for VMS severity, bother and interference. Low-dose estradiol reduced symptom frequency by 0.6 more per day than venlafaxine (95% CI, 1.8 more per day to 0.6 fewer per day than venlafaxine; p=0.09). Treatment satisfaction was highest (69%) on estradiol (p<0.001 versus placebo), lowest (39%) on placebo, and intermediate (52%) for venlafaxine (p=0.06 versus placebo). Both interventions were well tolerated.
Low-dose oral estradiol and venlafaxine are both effective treatments for vasomotor symptoms in midlife women. While efficacy of low-dose estradiol may be slightly superior to that of venlafaxine, the difference is small in magnitude and of uncertain clinical relevance.