To the Editor:

We want to thank Dr. Winslow and colleagues for their excellent review of fibromyalgia.¹ A patient recently presented to our practice who was taking recommended medications for fibromyalgia without much relief. The patient approached us about using low-dose naltrexone (Revia). A PubMed search showed that low-dose naltrexone (1 to 5 mg) has been used off-label to treat inflammation and pain in fibromyalgia, multiple sclerosis, and Crohn disease.² The mechanism of action is the modulation of neuroinflammation, specifically, the release of inflammatory chemicals in the central nervous system and the modulation of glial cells.³ Randomized, placebo-controlled trials are being conducted to add more data to the literature.^4,5 Although low-dose naltrexone shows promise in relieving pain symptoms for people with fibromyalgia, a challenge is its limited availability. Currently, oral naltrexone is available only in 50-mg tablets. Compounding pharmacies may be able to create low-dose naltrexone, but insurance coverage presents another challenge. After discussing the potential benefits and risks, the patient decided to try one-half of the 50-mg tablet and found some relief.