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  • Writer's pictureMegan Vardeman, PA-C

Low Dose Naltrexone (LDN)

Updated: Apr 17, 2023

A Potential Treatment Option for difficult to manage and treatment resistant mental health disorders and autoimmune conditions

Naltrexone is a drug that was first approved by the FDA in 1984 as a treatment for opioid addiction. Since that time, it has also garnered FDA approval for the treatment of alcohol use disorder and has been studied with positive results for the treatment of many other addictive disorders, including stimulant abuse and pathological gambling. Typical doses for addiction treatment range from 50 to 200 mg daily.

How Does LDN Work and Why is it Different than Traditional Doses of Naltrexone?

While its use in addiction is well-established, naltrexone really shines when used in low doses of less than 4 mg daily to modulate our natural reward and immune systems. It acts as an antagonist (blocker) of at least two different types of receptors in our body: opiate receptors and toll-like receptors.

Opiate Receptors

First, naltrexone is capable of blocking any of the various opioid receptor types in our body, which explains its efficacy at higher doses for addictions. Mu opioid receptors signal pleasure and reward and disrupting the reward response to a substance creates an opportunity for us to “unlearn” the addictive behavior. For this to work, we use high doses of naltrexone to be sure to completely block our body’s ability to “feel” the pleasurable effects of the substance. When we use low-dose naltrexone (LDN), however, the temporary and more minor blockade of these same receptors results in a signal to the body to work harder to produce more Mu Opioid receptors, which basically makes us extra sensitive to the impact of our own natural feelgood hormones (endorphins) and can further increase their levels. We believe this to be one reason why LDN is observed to be effective in pain management and depression.

Less commonly thought about are Opioid Growth Factor (OGF) receptors, which are present on many cells throughout the body and play a role in promoting cell proliferation, wound healing, and other immune functions. Studies suggest that LDN works via the blockade of these non-classical opiate receptors to positively influence healing and cell repair. This may be via a similar process of upregulation that we see in the Mu Opioid receptors, or by an entirely separate mechanism involving various immunological players, like B cells and astrocytes.

Toll-Like Receptors

Toll-Like Receptors (TLRs) are part of our immune system. When they are stimulated by external pathogens or internal “irritants,” they tell our bodies to respond to the threat with an inflammatory cascade, by releasing pro-inflammatory protein messengers called cytokines. LDN can bind and block TLRs, especially TLR-4, which prevents it from sending out the pro-inflammatory distress signals that it otherwise might in autoimmune conditions and chronic inflammatory processes.

How it All Ties Together

Through its action on both the opiate receptor groups and the toll-like receptors, low-dose naltrexone ultimately can help to correct runaway inflammatory or immune processes. Some observational studies have noticed a link between immune dysregulation (i.e., autoimmune conditions, chronic disease states, allergic responses, and insulin resistance) and lower-than-normal levels of natural circulating endorphins. We know that endorphins regulate more than just our natural reward response—they also affect cell growth throughout the body, and our immune response.

It is likely that the pain-alleviating properties of LDN result not only from higher endorphins and more “feel good” mu-opioid receptors, but also from its down-stream ability to modulate the immune system and reduce inflammation.

If you have been reading our posts and continue to read our posts, you will quickly realize we are obsessed with inflammation. Inflammation is the root cause of nearly all the conditions we treat. Our goal is to discover and uproot sources of inflammation in our patient’s lives. Once inflammation is under control, the body can begin its process of natural healing. LDN is a great tool to begin to disrupt that inflammatory process early on, while we work toward the longer-term changes that support an anti-inflammatory lifestyle.

LDN is currently used “off label” in the treatment of a wide variety of conditions, and the list of disorders and diseases it can treat continues to grow. Briefly, it has been studied in the treatment of autoimmune conditions, cancer, depression, anxiety, fibromyalgia, PMDD, PCOS, chronic pain, celiac disease, and gluten sensitivity, reactivated EBV, Lyme Disease, Autism, OCD, and it even appears to have favorable effects on fertility. The full list is much longer and continues to grow. It is truly an intriguing medication.

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