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Low-Dose Naltrexone for Chronic Pain: What You Should Know

Learn about the recent research conducted on low-dose naltrexone as a non-opioid alternative for chronic pain relief.

Dr. Abigail Hirsch, Ph.D
Reviewed by 
Dr. Kate Smith, MD
November 12, 2021
 min. read

You might feel like you’ve tried everything at this point to get rid of the chronic pain that continually troubles you. And on top of that, there’s frustration and maybe even anger at your inability to overcome this difficulty in your life. Well, you’re not alone: about 20% of your fellow U.S. citizens (that’s 50.2 million people!) struggle with chronic pain too.

Like you, many of them have tried to manage their recurrent pain using opioids, surgery, and other medications. As you likely know, there are multiple potential downsides to these treatments, including addiction, postoperative health issues, and nasty side effects, among others. As a result, it’s always a good idea to be open to alternative, non-pharmacological, and non-invasive methods of coping with your pain.

Naltrexone is an FDA-approved drug that has been in use for several decades. More recently, many people found success in taking smaller doses of it (referred to as low-dose naltrexone or LDN) to alleviate their chronic pain. This article examines some of the recent research conducted on low-dose naltrexone for chronic pain and its potential to provide pain relief with fewer side effects, risks, and costs than many other traditional treatments.

What is Low Dose Naltrexone?

Originally developed to treat opioid addiction, naltrexone was approved by the U.S. Food and Drug Administration (FDA) in 1984. At this higher dosage level it is used to treat addiction to heroin, oxycodone, and morphine and to inhibit alcohol cravings. In these cases, patients are typically given a dosage of 50 to 100 milligrams (mg) of naltrexone a day taken orally.

However, it was subsequently discovered that its use in significantly lower doses follow alternate pharmacodymanic pathways with other beneficial effects.  When used in a lower dosage range of 0.5-4.5 mg, LDN is seen to have immune-modulating, anti-inflammatory effects, along with up-regulation of endogenous opioid production. LDN has gained popularity as an off-label treatment (meaning an unapproved dosage amount) for several autoimmune and chronic pain conditions, mood disorders and cancer.  Although low-dose naltrexone isn’t yet approved by the FDA, it has shown to be promising in multiple clinical studies for the management of chronic pain.


How Does Low Dose Naltrexone Work?

Naltrexone temporarily binds to and blocks what’s called an MU receptor, which is found in the amygdala of the brain. When it blocks this receptor, it tells the body that it isn’t producing enough endorphins (the feel-good hormones) and then releases them. 

When a person is given a lower dosage of naltrexone, it’s believed that the drug then acts like a glial/immune cell modulator that lowers inflammation, thereby reducing pain. In other words, naltrexone is essentially an “anti-inflammatory agent in the central nervous system”.  The low dosing of naltrexone’s other mode of action involves transient opioid receptor blockade which results in increasing levels of endogenous opioid production, known as opioid rebound effect. There have been clinical reports that this low dose version of naltrexone has helped people with conditions like fibromyalgia, multiple sclerosis, cancer, Crohn’s disease, complex regional pain syndrome, and more.

The Use of Naltrexone for Pain Relief

The use of low dose naltrexone for chronic pain management is increasing in popularity because, unlike other drugs, naltrexone appears to fulfill what’s known as the 4 L’s: low risk, low side effects, low dose, and low cost. Compared to other traditional pain therapies that are frequently risky, expensive, and riddled with side effects, utilizing naltrexone low dose for pain seems like a great option.

The affordability of naltrexone is a huge plus. While some alternative pain treatments can cost hundreds of dollars out of pocket for patients, low-dose naltrexone only costs an average of $16 to $20 per month. It’s also very accessible, with some pharmacies selling it as an OTC supplement. 

Low dose naltrexone’s side effects are known to be minimal. They include insomnia, vivid dreams, hot flashes, exhaustion, and a possible increase in migraines. In one study, however, 75% of the people taking low-dose naltrexone experienced no side effects at all.

Additional benefits of LDN include no known abuse potential and no withdrawal effects.  LDN does not exert any euphoric or reinforcing effects, suggesting no potential for dependence. With cessation, there is usually a slow return of symptoms to baseline.

Various studies have supported the use of low-dose naltrexone for treatment of chronic pain, although more research needs to be done. One scientific case, for instance, that administered low-dose naltrexone to 35 patients with chronic pain that lasted between one and six months found that nearly half of the participants experienced either partial or significant pain relief and/or an increase in function.

Another study that reviewed all articles [in English] published between January 1980 and July 2018 on the topic of low-dose naltrexone pain management (85 papers) discovered that the drug in low dosage amounts helped patients impacted by fibromyalgia, Crohn’s disease, complex regional pain syndrome, irritable bowel syndrome (IBS), cancer, Hailey-Hailey disease, autism, diabetic neuropathy (Google “naltrexone neuropathy” for more information about this) multiple sclerosis, and others.

A study published in The Ocular Surface in April 2021 also found low-dose naltrexone to be beneficial - in this case for patients suffering from neuropathic corneal pain. Symptoms of this disease include pain, dryness, burning, and light sensitivity of the somatosensory nervous system (which includes receptors and nerve pathways for touch, pain, pressure, body temperature, body position, movement, and vibration). Fifty-nine patients with neuropathic corneal pain were administered low dose naltrexone; over the duration of the study, their mean pain score decreased by 49%.

Another 2021 study on low-dose naltrexone focused on patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), which affects both the immune and nervous systems. It confirmed the effectiveness and therapeutic benefits of using low-dose naltrexone for this condition.  

Should You Consider Low Dose Naltrexone?

While there are pros and cons to all chronic pain treatments, low-dose naltrexone has a lot of things going for it as a non-opioid alternative. It’s affordable, been successfully used for a long time, and doesn’t carry a lot of risk. Side effects tend to be minimal and the clinical research in support of its role in chronic pain healing keeps piling up. Lin supports a holistic pain management approach that tackles chronic pain from multiple angles. Sign up today, and we will pair you with a personal health coach who will create a tailored care plan for you. If incorporating a treatment like low-dose naltrexone into your plan is the right course of action for you, we’ll help you do that. Contact us today!

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