Background: ConclusionFibromyalgia is a chronic pain disorder characterized by diffuse
musculoskeletal pain, fatigue, sleep disturbance and cognitive impairment.
Objective: A significant number of fibromyalgia patients do not respond adequately to the current
drugs approved by the Food and Drug Administration (FDA) for fibromyalgia treatment including
pregabalin, milnacipran, duloxetine. Thus, there is still a need for adjunctive therapies.
Method: Naltrexone is an opioid receptor antagonist used to treat alcohol and opioid dependence. It
is hypothesized that low dose naltrexone causes transient blockade of opioid receptors centrally resulting
in a rebound of endorphin function which may attenuate pain in fibromyalgia.
Results: Two small prospective pilot studies have previously shown that treatment with low dose
naltrexone may be an effective, safe, and inexpensive treatment for fibromyalgia.
Conclusion: This prospective study lends further support to the preliminary body of evidence that
naltrexone is a well tolerated and likely effective treatment option in the community setting. Further
large prospective controlled trials are still needed.