Background: Hot flashes can be troublesome, especially when hormonal therapy is contraindicated. Preliminary data have suggested that newer antidepressants, such as venlafaxine, can diminish hot flashes. We undertook a double-blind, placebo-controlled, randomised trial to assess the efficacy of venlafaxine in women with a history of breast cancer or reluctance to take hormonal treatment because of fear of breast cancer.
Methods: Participants were assigned placebo (n=56) or venlafaxine 37.5 mg daily (n=56), 75 mg daily (n=55), or 150 mg daily (n=54). After a baseline assessment week, patients took the study medication for 4 weeks. All venlafaxine treatment started at 37.5 mg daily and gradually increased in the 75 mg and 150 mg groups. Patients completed daily hot-flash questionnaire diaries. The primary endpoint was average daily hot-flash activity (number of flashes and a score combining number and severity). Analyses were based on the women who provided data throughout the baseline and study weeks.
Findings: 191 patients had evaluable data for the whole study period (50 placebo, 49 venlafaxine 37.5 mg, 43 venlafaxine 75 mg, 49 venlafaxine 150 mg). After week 4 of treatment, median hot flash scores were reduced from baseline by 27% (95% CI 11-34), 37% (26-54), 61% (50-68), and 61% (48-75) in the four groups. Frequencies of some side-effects (mouth dryness, decreased appetite, nausea, and constipation) were significantly higher in the venlafaxine 75 mg and 150 mg groups than in the placebo group.
Interpretation: Venlafaxine is an effective non-hormonal treatment for hot flashes, though the efficacy must be balanced against the drug's side-effects. Confirmation of the results of this 4-week study awaits the completion of three ongoing randomised studies to assess the effects of other related antidepressants for the treatment of hot flashes.