Questioning the likelihood that sodium oxybate can be used to successfully treat fibromyalgia: Comment on the article by Russell et al

To the Editor:

I read with interest the recent report by Russell et al on the reults of a trial evaluating the effects of sodium oxybate in patients with fibromyalgia (Russell IJ, Perkins AT, Michalek JE, and the Oxybate SXB-26 Fibromyalgia Syndrome Study Group. Sodium oxybate relieves pain and improves function in fibromyalgia syndrome: a randomized, double-blind, placebocontrolled, multicenter clinical trial. Arthritis Rheum 2009; 60:299–309), and I sincerely commend the investigators for conducting such a study. From the practical point of view, however, and based on my clinical experience with fibromyalgia patients, I question how likely it is that, in the long-term, patients will continue to take a medication that may help only 30% of them, while at the same time continuing to abstain from taking opiates, antidepressants, cyclobenzaprine, and tramadol, and from drinking alcohol. Furthermore, will patients be willing to set their alarm clocks and interrupt their sleep in order to take a second dose of the medication? And, given the number of additional exclusion criteria in the study by Russell and colleagues, what population of fibromyalgia patients will actually be able to take sodium oxybate, when and if this drug is used outside the context of a clinical trial?

Also, as a point of clarification, the study by Russell et al was a randomized clinical trial. It is not a prospective study, as the authors refer to it in the Discussion section of their report, since it is not a study in which patients who were either exposed and not exposed to a given risk are followed up over time for the occurrence of a given disease (see www.statsdirect.com/help/basics/prospective.htm). Unfortunately, inappropriate use of the terms “retrospective” and “prospective” is common in the medical literature, and the journal should not perpetuate this error.

Graciela S. Alarcón MD, MPH*, * University of Alabama at Birmingham.