Low Dose Naltrexone (LDN): Possibly a Major Breakthrough

Background

Naltrexone is an FDA approved medicine used to block the effects of opiate pain medicines such as codeine, oxycodone or OxyContin.  At its usual dose of 50 mg Naltrexone tends to increase sensations of pain because it also blocks the action of the body’s own natural opiate-like compounds. But at much lower doses, in the 3-4 mg range, LDN has long been used by alternative medicine-minded clinicians as a treatment for pain, fatigue and other symptoms. The key insight here is that very low doses of Naltrexone don’t harm our body’s natural opiates. Rather, at low doses, Naltrexone seems to act to reduce our sense of pain.

LDN and pain
LDN and pain

LDN helps a meaningful proportion of FM patients—perhaps 40%. And, its side effect profile has been relatively benign—almost certainly more favorable than our standard FM drugs. As importantly, LDN’s proposed mechanism, suppression of inflammatory chemicals (cytokines) within the central nervous system might lead toward a new approach for a broad range of diseases.

 

Study

double blind study was conducted by Jarred Younger PhD, and Sean Mackey, M.D., PhD  from the Stanford Medical School’s Division of Pain Management. Thirty one women with Fibromyalgia were each treated with 4.5 mg of naltrexone in the evening for 12 weeks and a placebo for 4 weeks.

Results

Reduction in pain scores compared to baseline were significantly greater during the LDN period compared to placebo. (28.8% reduction versus 18% reduction; P=0.016). LDN was also associated with improved general satisfaction (P=.045) and better mood (P=0.039). Thirty two percent of participants had an improvement in both pain and either fatigue or sleep while on naltrexone in contrast to an 11% response rate during placebo (P=0.05). The #1 “side effect” was increased dreaming, which some subjects felt were disturbing.

Other than a small pilot trial done earlier by the Stanford group, I believe that Younger and Mackey’s study is the only academically sound test of LDN for Fibromyalgia.  However, I and at least one other CFS-ME/Fibromyalgia specialist (Nancy Klimas, M.D, PhD personal communication) have found LDN useful. LDN is not a cure-all, but it seems to help a substantial proportion of patients. Dramatically exciting is LDN’s proposed mechanism, suppression of cytokines and brain immune cells called microglial cells. This brain-anti-inflammatory approach might also apply to other difficult to treat neurological conditions.

Fibromyalgia is known to have an element of central nervous system inflammation as do other brain related diseases including Multiple Sclerosis, Parkinson’s and Alzheimer’s.  Would LDN also help these conditions? Hopefully, more research will follow.

Take Home Thoughts

Low dose naltrexone helps relieve pain in a substantial proportion of people with Fibromyalgia. In some people it might also help with fatigue and mood, although that part has not been formally tested in studies.  Not all patients tolerate LDN but the most frequent side effects, increased dreaming and headache, are not dangerous and often decrease over time. Except for people who regularly take narcotics, it is reasonable to consider a trial of LDN.  For these reasons, clinicians who treat FM and/or CFS/ME should consider themselves obligated to learn more about LDN and, with informed consent, consider offering it to selected patients.

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