Venlafaxine for Fibromyalgia: Do Studies Support Efficacy?
the MPR take:
The serotonin and norepinephrine reuptake inhibitor (SNRI) venlafaxine is used by almost a quarter of all patients diagnosed with fibromyalgia, yet support for its efficacy in this patient population is limited. In a systematic review in the Journal of Clinical Pharmacy and Therapeutics, data from four open-label cohort studies and one randomized controlled trial was investigated on venlafaxine in fibromyalgia. All open-label studies showed improvement in symptoms or global function with venlafaxine, but they did not take into account the placebo effect. The randomized controlled study only saw an improvement in Fibromyalgia Impact Questionnaire (FIQ) score in patients, but not for the Visual Analog Score (VAS) or the McGill Pain Questionnaire (MPQ) score. The studies reviewed were limited by small sample size, inconsistent dosing, lack of placebo control, and lack of blinding. While it is believed that SNRIs may be beneficial for fibromyalgia due to observed low levels norepinephrine and serotonin in these patients, larger randomized controlled trials are necessary for greater understanding of the efficacy and safety of all SNRIs, including venlafaxine, for fibromyalgia.
What is known and objective? Fibromyalgia is a painful disease affecting 1-2% of the United States population. However, efficacy data are limited for the SNRI venlafaxine despite its use in nearly a quarter of patients with fibromyalgia. Results were classified as primary studies or review articles based on abstract review.
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