Low dose Naltrexone for fibromyalgia

Dr. Jarred Younger has been researching the potential use of Naltrexone for Fibromyalgia pain relief since 2009. One of his earliest studies examined the effect of 50mg of Naltrexone on Fibromyalgia patients and found no significant results. That same year he published a pilot study examining the effects of naltrexone at a much lower dose (4.5mg).

Higher dosages of Naltrexone (50mg) act as an Opioid Antagonist, meaning that the drug blocks the effects of opioids. For that reason these drugs are often used to treat opioid addiction. At the much lower dose of 4.5 mg it is believed that Naltrexone may act as an anti-inflammatory instead of as and opioid antagonist. Low-dose Naltrexone may also act to inhibit microglia activity. Overactive mycroglia are have been linked to neuronal cell death in many diseases, including Parkinsons and MS.

Younger’s initial pilot study in 2009 included 10 women with Fibromyalgia who were not taking opioids. First a baseline level of pain was established over the course of 2 weeks, followed by 2 weeks taking a placebo drug, then eight weeks taking low dose Naltrexone, followed by a 2 week wash-out period. Overall, the study showed that low-dose naltrexone reduced symptoms by 30% or more for 6 out of the 10 participants.

In 2013 Younger and colleagues published another small study. This time he included 31 women with Fibromyalgia and used a similar method. This time all participants started with a 2 week placebo period, and then were randomly assigned to one of two groups.

Group 1 received placebo for 4 weeks followed by 12 weeks of treatment, ending with a 4 week follow-up.

Group 2 began with the 12 weeks of treatment, then 4 weeks of placebo and 4 week follow-up. They removed the wash-out period to keep the participants from having the idea that they were being switched from one medication to another.

This time there was a 28.8% reduction in pain during the treatment period, compared to an 18% reduction during the placebo period.

57% of the participants saw at least at 30% improvement in pain. Participants also showed an improvement in mood and overall quality of life ratings; however, there was no effect on sleep or fatigue levels.

30% is the goal here.

It seems pretty low to me, but this 30% mark is pretty typical for most Fibromyalgia treatments, and it’s the benchmark for approval of pharmaceutical medications. If you look at any of the primary treatments that are approved for treating Fibromyalgia, the success rate is only about 30% improvement, about 30% of the time.

From the numbers they are presenting here you have about a 50% chance of seeing a 30% improvement, which is a slight improvement over the standard.

This was still a pretty small study, and I know that many doctors are already using this treatment off-label, as I’ve heard from a few of you who are trying it. So far, most everyone I’ve talked to who has tried low-dose Naltrexone for fibromyalgia has reported a positive experience. That’s better than I can say for most meds out there.

Given how much off-label use this is starting to get I’m really surprised we haven’t seen more research studies on the use of low dose naltrexone for fibromyalgia.

If you are on Low dose Naltrexone for Fibromyalgia (or have tried it) please comment below and share your experience.

References:

Younger J, Noor N, McCue R, Mackey S. Low-dose naltrexone for the treatment of fibromyalgia: findings of a small, randomized, double-blind, placebo controlled, counterbalanced, crossover trial assessing daily pain levels. Arthritis and Rheumatism 2013;65(2):529–38.

Younger, J., Noor, N., McCue, R., & Mackey, S. (2013). Low-dose naltrexone for the treatment of fibromyalgia: Findings of a small, randomized, double-blind, placebo-controlled, counterbalanced, crossover trial assessing daily pain levels. Arthritis & Rheumatism, 65(2), 529-538. doi:10.1002/art.37734