Low-dose estradiol and the serotonin-norepinephrine reuptake inhibitor venlafaxine for vasomotor symptoms: a randomized clinical trial

Abstract

Importance: 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 hydrochloride is used widely as a nonhormonal treatment. While the 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 date.

Objective: To determine the efficacy and tolerability of low-dose oral 17β-estradiol and low-dose venlafaxine extended release in alleviating vasomotor symptoms (VMS).

Design, setting, and participants: In total, 339 perimenopausal and postmenopausal women with at least 2 bothersome VMS per day (mean, 8.1 per day) were recruited from the community to MsFLASH (Menopause Strategies: Finding Lasting Answers for Symptoms and Health) clinical network sites between December 5, 2011, and October 15, 2012.

Interventions: Participants were randomized to double-blind treatment with low-dose oral 17β-estradiol (0.5 mg/d) (n = 97), low-dose venlafaxine hydrochloride extended release (75 mg/d) (n = 96), or placebo (n = 146) for 8 weeks.

Main outcomes and measures: The primary outcome was the mean daily frequency of VMS after 8 weeks of treatment. Secondary outcomes were VMS severity, bother, and interference with daily life. Intent-to-treat analyses compared the change in VMS frequency between each active intervention and placebo and between the 2 active treatments.

Results: Compared with baseline, the mean VMS frequency at week 8 decreased to 3.9 (95% CI, 2.9-4.9) VMS per day (52.9% reduction) in the estradiol group, to 4.4 (95% CI, 3.5-5.3) VMS per day (47.6% reduction) in the venlafaxine group, and to 5.5 (95% CI, 4.7-6.3) VMS per day (28.6% reduction) in the placebo group. Estradiol reduced the frequency of symptoms by 2.3 more per day than placebo (P < .001), and venlafaxine reduced the frequency of symptoms by 1.8 more per day than placebo (P = .005). The results were consistent for VMS severity, bother, and interference. Low-dose estradiol reduced the frequency of symptoms by 0.6 more per day than venlafaxine (P = .09). Treatment satisfaction was highest (70.3%) for estradiol (P < .001 vs placebo), lowest (38.4%) for placebo, and intermediate (51.1%) for venlafaxine (P = .06 vs placebo). Both interventions were well tolerated.

Conclusions and relevance: Low-dose oral estradiol and venlafaxine are effective treatments for VMS in women during midlife. While the efficacy of low-dose estradiol may be slightly superior to that of venlafaxine, the difference is small and of uncertain clinical relevance.

Trial registration: clinicaltrials.gov Identifier: NCT01418209.

Figure 1

CONSORT Diagram

Figure 2

Vasomotor Symptom (VMS) Frequency by Treatment Arm