In the United States, approximately 10 million people are affected by Fibromyalgia, making it one of the most widespread types of chronic pain. Fibromyalgia is a chronic condition characterized by muscle and joint pain, but often accompanied by a variety of other symptoms such as anxiety, sleeping problems, fatigue and morning stiffness, to name a few. While a variety of both drugs and alternative treatment options are currently available for fibromyalgia, recently the drug naltrexone has been on the rise as a possible treatment for those with chronic muscle pain, providing a new source of hope for those with fibromyalgia.

Naltrexone is a drug that is typically used to prevent opioid relapse in those who have become addicted, and is often a part of both drug and alcohol treatment programs. Its effectiveness as such a drug comes from its classification as an opioid antagonist. An opioid antagonist is a drug that binds to the same receptors as opioids do in the body, but with more success than opioids due to the higher affinity they have towards the receptors. By out-competing the opioids and binding to the receptors, they effectively “block” the opioids and prevent them from binding. Because Naltrexone does not react with the receptors in the same way opioids would, such binding does not cause a release of endorphins, ultimately preventing the opioids from producing any sort of pleasurable effect in the patient. Naltrexone works in a similar way to combat alcoholism. If taken before drinking alcohol, the drug binds to receptors within the brain that endorphins would otherwise bind to after alcohol consumption. In both cases, the most common use of the drug is to prevent the brain’s processing of endorphins from the consumption of a harmful substance. 

Though it is traditionally used to aid against narcotics relapse, low dose naltrexone (LDN) is also a possible treatment for Fibromyalgia. While oftentimes opiates themselves are used as treatments for those with chronic pain conditions, what makes LDN unique is that it is the opposite, an opiate-blocker. It is called low-dose naltrexone because, whereas 50mg doses are often used in the treatment of opioid or alcohol addiction, 1-5mg doses are typical when it is used as a drug for fibromyalgia. But how does naltrexone work to combat chronic joint and muscle pain? Because the exact cause of fibromyalgia is still unknown, a definite conclusion has not yet been developed. There are two main theories, however, that explain how this is accomplished. The first theory is that endorphin levels may be abnormal low for patients suffering from chronic pain conditions such as fibromyalgia. When naltrexone blocks endorphin receptors it may trick the body into producing more of the “natural painkiller.” By doing so, the symptoms of pain from fibromyalgia may be lessened. Another theory centers around LDN’s interaction with glial cells in the brain and spinal cord. Glial cells begin to release inflammatory chemicals if the brain sends chronic pain signals, which aggravates surrounding nerve cells and makes them more sensitive to pain signals. While other drugs target the inflamed nerve cells, LDN interacts with the glial cells themselves, binding to specific receptors that essentially cause the cells to stop releasing inflammatory chemicals, which greatly reduces pain symptoms. 

Since naltrexone is still a new form of treatment for chronic pain, there is still a great deal of research to be done about potential risks and side-effects. However, as of now almost no negative side-effects have been reported as a result of LDN, and the ones that have been were typically very mild, such as vivid dreams or difficult falling asleep. If taken in larger doses, naltrexone may cause symptoms including yellowing of the skin or eyes, heightened fatigue, loss of appetite, or unusual bleeding. However, these risks are typically not associated with naltrexone as a treatment for fibromyalgia, due to the much smaller dosage of the drug. It is possible for naltrexone to interact with other drugs being taken by the patient. Opioids, disulfiram, thioridazine, and certain cough, pain, or diarrhea medicines in particular may cause adverse reactions if mixed with naltrexone. Alcohol consumption should also be avoided while taking naltrexone. 

If you are suffering from fibromyalgia, low dose naltrexone may be a fitting treatment option. With few side-effects, a high success rate, and a low cost, LDN is proving to be a viable pathway for fibromyalgia treatment, and is increasing in popularity. If this option seems right for you, talk to your doctor about starting a treatment with low dose naltrexone.