Last Friday, Wyeth received FDA approval for the antidepressant desvenlafaxine succinate (marketed under the name Pristiq), a metabolite of venlafaxine or Effexor. Although this drug was approved for the treatment of major depression, a recent study has demonstrated that desvenlafaxine could be an effective treatment for vasomotor symptoms in postmenopausal women.

Many women report vasomotor symptoms, including hot flushes and night sweats, during the menopausal transition. While estrogen is clearly one of the most effective treatments for vasomotor symptoms, recent concerns regarding the use of hormone replacement therapy (HRT) have made treaters much more reluctant to recommend HRT, even for short-term management of vasomotor symptoms.

A randomized, double-blind, placebo-controlled trial enrolled 707 healthy, postmenopausal women (mean age was 53.47 yrs, range 37–78) experiencing 50 or more moderate-to-severe hot flushes per week. Participants were randomized to receive one of four doses of desvenlafaxine (50, 100, 150, or 200 mg/day) or placebo for 52 weeks. Throughout the study, women maintained daily diaries for recording the frequency and severity of hot flushes. 620 women completed at least one follow-up evaluation; 519 participants completed 12 weeks of treatment, and 368 completed the entire study.

Women receiving desvenlafaxine 100 mg/day experienced a 64% reduction from baseline in the number of hot flushes. Evidence of efficacy was demonstrated as rapidly as within one week of initiation of treatment. Although placebo response rates were high (up to 50%) desvenlafaxine-treated women had a significantly greater reduction in number of hot flushes compared to women receiving placebo at weeks 4 (p=.013) and 12 (p=.005). Desvenlafaxine was generally well tolerated at all doses tested. Women treated with desvenlafaxine reported significantly more treatment-emergent adverse events than placebo-treated women during the first week of therapy only. The most common side effects were nausea, dizziness, and insomnia, and there were some cases of adverse cardiac-related events in women taking desvenlafaxine.

These results are consistent with previous studies suggesting that selective serotonin or serotonin-norepinephrine reuptake inhibitors (SSRIs and SNRIs) may be helpful for the treatment of vasomotor symptoms in peri- and postmenopausal women. These findings suggest that desvenlafaxine may provide an effective non-hormonal therapy for moderate-to-severe vasomotor symptoms associated with menopause. The FDA has asked Wyeth to collect more safety data prior to approving Pristiq for this purpose to ensure that the benefits of taking the drug for vasomotor symptoms outweigh the adverse events.

Ruta Nonacs, MD PhD

Speroff L, Gass M, Constantine G, Olivier S; Study 315 Investigators. Efficacy and tolerability of desvenlafaxine succinate treatment for menopausal vasomotor symptoms: a randomized controlled trial. Obstet Gynecol. 2008 Jan;111(1):77-87.

Nelson HD, Vesco KK, Haney E, Fu R, Nedrow A, Miller J, Nicolaidis C, Walker M, Humphrey L. Nonhormonal therapies for menopausal hot flashes: systematic review and meta-analysis. JAMA. 2006 May 3;295(17):2057-71.

NY Times article: F.D.A Approves Wyeth Antidepressant