Low-Dose Naltrexone

LOW-DOSE NALTREXONE New research has brought our attention to the tremendous potential of low-dose naltrexone to help people with chronic pain. We have used this treatment in hundreds of patients with a wide range of health problems, but we recently began prescribing it for patients in our chronic pain program with very encouraging results.

Naltrexone is a drug that was introduced in the 1960s, initially for the treatment of addiction to heroin and alcohol. Researchers found that it blocks the opioid receptors that bind to endorphins, the body’s natural pain-killers. People on naltrexone could not get high when using the illicit drugs they were addicted to. It was used for several years for this purpose.

In the early 1990s, naltrexone was rediscovered by a physician named Dr Bihari treating people with HIV in New York city. Using a low dose of 4.5mg (as compared to the 100300mg doses used to treat addiction), Dr Bihari saw major improvements in the immune function of these patients. He described his experience in this paper.

Since then, a grassroots movement has developed around the world, which has led thousands of people to use low-dose naltrexone (LDN) to treat a wide range of diseases of the immune system, including cancers and some neurological disorders. It is known that endorphins do much more than relieve pain. These feel-good molecules, whose release can be triggered by exercise, sex and other activities, stimulate many cells of the immune system.

While high doses of naltrexone block endorphins completely, low doses seem to lower them just a little bit - leading the body to increase its production of endorphins. The first published study of LDN was in patients with Crohn’s disease, followed by another in children with Crohns. Ongoing trials are evaluating LDN in multiple sclerosis and in cancer.

More recent studies have shown early positive results in treating chronic pain.

Researchers at Stanford University published two clinical trials showing that LDN reduced chronic pain in women with fibromyalgia. A case series showed pain reductions in two people with complex regional pain syndrome, and many physicians are using it to treat chronic low back pain as described in this paper.

Studies suggest that LDN may heal the body in more ways than one. In addition to helping boost endorphin levels, naltrexone binds to the TLR4 receptor on cells in the brain that are called microglia. These housekeeping cells keep the brain healthy, but when they are activated they can trigger inflammation in the brain.

Chronic pain turns on microglia, leading them to trigger inflammation in the entire nervous system. This causes pain, but it also promotes sleep problems, depression, anxiety and affects memory and concentration. It seems that naltrexone turns off microglia, leading to an anti-inflammatory effect in the brain.

People using opioid medications, including morphine, codeine, hydromorphone, oxycodone, tramadol, cannot use LDN. This interaction can cause bizarre side-effects, so a two-week washout period is needed before starting LDN. These are the only drugs that interact with LDN. For the first week or two, people starting LDN can have more trouble sleeping. This occurs because the body is adjusting to lower endorphin levels, and it takes time for it to increase its production of these natural pain killers. During this time, I advise patients to use melatonin, chamomile tea, epsom salt baths and other natural sleeping aids as needed.

Clinical trials evaluated LDN over a 12-week period. In most cases, people will see improvements within two months. It is not manufactured on a large scale at this very special dose, so LDN prescriptions are filled by compounding pharmacies. If you feel that a two-month trial has improved your symptoms, function or quality of life, you can continue using LDN over the long-term.

Hopefully further studies will reveal the optimal dosing, duration and the specific conditions for which it works best. While evidence is important, the only way to tell whether it works for you is to try it and see. This is called rational prescribing, and it is an approach that can help patients and prescribers explore integrative medicine more safely and responsibly in keeping with the principles of evidence-based medicine.