Naltrexone was originally used to help treat alcohol and opioid abuse. However, at lose doses, naltrexone has been found to help with chronic pain stemming from various conditions including fibromyalgia, Crohn’s disease, diabetic neuropathy, axial low back pain, rheumatoid arthritis, and complex region pain syndrome. To better understand this clinical use, researchers at the University of Kansas Medical Study conducted a literature review and determined that naltrexone does show benefit in improving pain, function, and symptom severity, although more research is needed.

Adam Rupp, DO, reports that there is significant variability in the design of existing studies making it difficult to draw definitive conclusions. However, the team found some trends including improvements in pain for up to the duration of the trial (1-12 months), improvement in function, improvements in symptom severity (sleep, mood, work capacity, fatigue), and even improvements in the colon’s appearance with colonoscopy for those with Crohn’s disease. Side effects were minimal, ranging from 0-33%, and consisted most commonly of trouble sleeping, vivid dreams, headaches, and nausea. Most of these side effects resolved with continued use of the medication. A very small minority of patients stopped taking low-dose naltrexone, usually due to intolerance of the side effects or not having a response.

Dr. Rupp noted that caution should be taken when interpreting the results of this review, as the studies were extremely variable and only few were controlled for extraneous variables.

“Though the results look promising, further, more well controlled studies are required before formal recommendations can be made,” he said.