Naltrexone is an old drug with many uses that was first developed in 1963. Its initial use was for treating opioid addiction. The drug is a derivative of the opioid oxymorphone but acts in the opposite way at regular doses to block the opioid receptors in the body. Naltrexone also has an effect to suppress the desire to consume alcohol, and won approval for this in 2006. The normal dose of naltrexone is 50 mg, while low dose Naltrexone ranges between 1.5 mg to 4.5 mg per day. The use of low dose Naltrexone began in the 1980’s and over the last several years some practitioners have been using this for pain care.
How Naltrexone Works
The use of a drug that blocks opioids to treat pain appears to be counter-intuitive. At low doses, many medications have different properties and effects than when given at higher doses. Medications like Naltrexone seem to decrease the inflammatory response of microglia in the central nervous system. Prolonged painful stimuli impairs the nervous system and the body’s ability to regulate endorphins. Resetting the central sensitivity to pain is what Naltrexone may do, but it tends to work in cases only when there is not ongoing tissue damage or stimulation of inflammatory factors. It would not work in degenerative arthritis or spinal issues causing acting nerve stimulation. The best use is in fibromyalgia, migraines and central sensitization of the nervous system.
The important factors related to low dose naltrexone and pain are that it affects the microglia in the central nervous system. The microglia are immune cells in the CNS and produce compounds that are excitatory and inflammatory. These can result in pain sensitivity, fatigue, cognitive disruption, mood disorders, and general malaise. Naltrexone can have a neuroprotective and analgesic effect in the nervous system by suppressing microglia activity. When pain is being produced by an overactive nervous system, then this medication may be helpful.
Low dose naltrexone is experimental. There is no FDA approval for such dosing but it has been approved for treatment of other medical conditions at doses ten times higher than what is recommended for pain. It is a generic compound, and can be made by a pharmacist into a capsule at some pharmacies. The cost is about $40 a month, it likely would not be covered by insurance and could be considered a reasonable option when other treatments have not been effective for chronic pain, fibromyalgia, central pain states and migraine headaches. The side effect profile is very low, the most common are vivid dreams and tiredness. There is limited hard research on Naltrexone at low dose, but the most common dosing is 4.5 mg once a day, lower doses down to 1.5 mg and higher or more frequent dosing have been used as well. Dosing is based on the drug’s activity in the body and its breakdown and metabolism.
At this time, if one has chronic pain with definite central pain sensitivity, the use of low dose Naltrexone is experimental. If conventional treatments are not effective, it may be worthwhile to consider trying this medication. If one of the main problems one suffers is fibromyalgia, migraines or a similar condition, it may be reasonable to trial this medication. It probably will not be approved by insurance, and you may have to travel to a pharmacy that can prepare the capsules. It has a low risk and it may be helpful.