In April 2009 I told you about a pilot study in which low-dose naltrexone (LDN) showed great promise as a fibromyalgia treatment. In that study, all 10 of the participants reported a reduction in fibromyalgia symptoms, with 60% of them experiencing more than a 30% reduction in pain and fatigue.
More recently, Jarred Younger, PhD, of Stanford University School of Medicine, and colleagues (authors of the first study) presented their findings from a second LDN study at the American Academy of Pain Medicine meeting.
The investigators expanded on their original LDN research by conducting a placebo-controlled, double-blind, crossover trial of 30 women with fibromyalgia. They found that half of the women reported feeling very much or much improved and an additional 25% said they felt minimally improved while taking the LDN. The only side effects reported were vivid dreams (37%) and headache (16%).
Naltrexone is an opioid receptor antagonist and is FDA approved for the management of alcohol and opioid addiction. However, its effectiveness at low doses with fibromyalgia is not due to its opioid antagonistic effects but is thought to be related to its ability to stifle an immune response which causes inflammatory cytokines to be released.
Survey of FM Patients: Naltrexone Gets High Scores
CureTogether is a Website that gathers patients around the world together to share information and compare the effectiveness of treatments. They conducted a survey of fibromyalgia patients who were taking LDN and found that 26 out of 44 reported a major improvement in symptoms since starting the LDN – that's 59%. In fact, LDN was ranked and the #1 most effective treatment for FM by their members, followed by rest, getting enough sleep, hot showers/baths and heating packs/pads.
It's also interesting to note, in a CureTogether survey of ME/CFS patients, they found that although not as many ME/CFS patients had taken LDN, those who had found it to be the most effective medication they had tried.
Both the study authors and the survey sponsors are careful to note that additional studies need to be done to further determine the effectiveness for LDN for fibromyalgia. However, I have serious doubts as to whether really extensive clinical trials will ever be conducted. Naltrexone is already avaliable as a generic drug, so there is little motivation for the pharmaceutical manufacturers to spend the millions of dollars it takes to get it approved for fibromyalgia. Unless they can somehow change it enough that they could submit it to the FDA as a new drug, it will probably have to continue to be prescribed off-label for fibromyalgia and/or ME/CFS.
Younger J, Mackey S. “Fibromyalgia Symptoms Are Reduced by Low-Dose Naltrexone: A Pilot Study” Pain Med. 2009 May–Jun; 10(4): 663–672.
Younger J, et al "Low-dose naltrexone reduces the symptoms of fibromyalgia: A double-blind and placebo-controlled crossover study" AAPM 2012; Abstract 251.
Fiore, K. “Naltrexone May Lessen Chronic Pain.” MedPage Today. February 26, 2012.