Low-Dose Naltrexone for Fibromyalgia and ME/CFS

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Naltrexone is a prescription drug that, at a normal dose of 50 to 100 milligrams (mg), blocks the effects of opioids, a class of drugs often taken for pain relief. Opioids include illegal drugs like heroin, as well as synthetic pain relief drugs like Vicodin (hydrocodone-acetaminophen).

At very low doses, however, some researchers believe that naltrexone may be able to help people with fibromyalgia, a long-term condition that can cause widespread pain, as well as chronic fatigue syndrome, a condition that causes exhaustion and general discomfort.

Medication being poured into hand.
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This article explores the research on using low-dose naltrexone (LDN) for fibromyalgia and chronic fatigue syndrome. It will also cover appropriate dosage and possible side effects.

How Does LDN Work?

Researchers don't yet understand how LDN works when it comes to fibromyalgia and chronic fatigue syndrome. Some researchers believe that LDN:

  • Blocks certain proteins that cause symptoms of fibromyalgia and chronic fatigue syndrome in the nervous system, which is the primary controlling and communicating system in the body
  • Works as an anti-inflammatory, which reduces inflammation or swelling, in the nervous system
  • May help keep the immune system, or what protects the body from harmful invaders, well-balanced, which may be why it tends to help people with immune system related illnesses
  • Temporarily blocks receptors associated with pain and triggers the release of endorphins, the body's natural painkillers

Can LDN Be Used to Treat Fibromyalgia?

Small studies have shown that individuals taking LDN to treat fibromyalgia showed as much as a 30 percent decline in symptoms compared to those given a fake treatment. Results tended to be best in those who had an inflammatory response, which is when the immune system responds to injury or illness. The drug was also well tolerated, with minimal side effects.

Keep in mind that LDN is not FDA-approved for fibromyalgia, but is sometimes prescribed. This is known as off-label use.

Recap

Small studies have shown that LDN may be helpful in reducing symptoms in those with fibromyalgia.

Can LDN Be Used for Chronic Fatigue Syndrome?

So far, LDN has not been studied in a clinical trial for chronic fatigue syndrome, but it is sometimes prescribed off-label. There is growing evidence that some individuals have seen a reduction in their symptoms while using LDN.

Research suggests that individuals with chronic fatigue syndrome may have neuroinflammation, which is an inflammatory response in the brain or spinal cord. Because LDN may have an impact on inflammation in the nervous system, it's understandable why this may be a helpful treatment for some.

Recap

LDN is sometimes prescribed off-label for chronic fatigue syndrome, a condition associated with inflammation. LDN may be helpful because it tends to have an impact on inflammation.

What Dosage Should I Take?

For use in treating fibromyalgia or chronic fatigue syndrome, naltrexone is generally given in doses of 4.5 mg or less. Typically, you'll start at 1.5 mg, work up to 3 mg, then increase to 4.5 mg.

Keep in mind that higher doses of naltrexone have not been shown to have the same symptom-reducing effects for fibromyalgia or chronic fatigue syndrome.

What Are the Side Effects of Naltrexone?

While LDN appears to be well-tolerated, known side effects of naltrexone include:

People with kidney disease, which is the loss of kidney functioning, or liver disease, which is when the liver becomes damaged over time, may need to speak with their doctor before starting LDN. Those who are pregnant or breastfeeding should also speak with their doctor before starting this medication.

Recap

Although LDN tends to be well tolerated, some may experience side effects. Those with certain conditions should speak with their doctor before trying this treatment.

How Does LDN Interact With Opioids?

In larger doses, naltrexone is used to help people taper off of opiate painkillers such as Ultram (tramadol) and OxyContin (oxycodone) because it blocks their effect on the brain.

Its effect on opiate use at low doses isn't known yet, but it's considered a bad idea to combine these drugs. Be sure to talk to your healthcare provider about how long you should be off of opioids before starting LDN.

Summary

Researchers aren't sure exactly how LDN works when it comes to fibromyalgia and chronic fatigue syndrome. Some believe it may act as an anti-inflammatory, help balance the immune system, or trigger the release of endorphins.

In research and case studies LDN has been shown to help decrease symptoms of both fibromyalgia and chronic fatigue syndrome with minimal side effects.

A Word From Verywell

If you're interested in trying LDN, talk to your healthcare provider about the possible pros and cons. Keep in mind that not all healthcare providers will prescribe LDN for people with fibromyalgia or chronic fatigue syndrome, as it's still considered an emerging treatment.

Frequently Asked Questions

  • Why is only a low dose of naltrexone prescribed for fibromyalgia?

    At high doses, naltrexone has a different effect on the body's systems.

  • Should I worry about serious side effects with low-dose naltrexone?

    Side effects are not common with low-dose naltrexone. In rare instances, there can be severe side effects such as confusion, vomiting, and diarrhea. Contact your healthcare provider right away if you experience these signs.

  • Is it safe to take low-dose naltrexone for long periods of time?

    Yes. Research shows that the drug seems safe for long-term use. As long as naltrexone benefits you, you can take it on an ongoing basis.

  • What else can LDN be used for?

    Other conditions where low-dose naltrexone is being explored include:

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11 Sources
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