Drug Naltrexone, Which Treats Addiction, May Also Treat Chronic Pain

Woman on walking trail holding back next to bottle of naltrexone

Some patients with chronic, almost untreatable pain have been put on a new drug regimen using small doses of a medication typically reserved to treat addiction: naltrexone. 

This unconventional treatment comes in the midst of the opioid epidemic, which grew after two decades of drug reps encouraging doctors to prescribe opioids to treat chronic pain. With the crackdown on opioid prescriptions, chronic pain sufferers are now left without effective treatment but in just as much pain. This breakthrough might give patients a safe, effective alternative to opioids.

What is naltrexone?

Naltrexone is usually prescribed in 50 mg doses (either pills or injection) to treat alcohol and opioid addiction. The drug works by blocking opioid receptors, which are responsible for many of the brain’s feel-good chemicals. This prevents patients from craving opioids that give them the high that can result from filling these receptors. 

Scientists believe that people with chronic pain have overly-sensitive central nervous systems, which are stuck in out-of-control feedback loops that drown out the body’s natural pain relievers. Research at the National Institutes of Health (NIH) also believe that low-dose naltrexone (LDN)—about 4.5 mg—may help dampen inflammation, encouraging the body to produce more pain-killing endorphins. 

Pilot studies have used LDN to treat multiple sclerosis, peripheral neuropathy, and even aid in weight loss. 

When will it become widely available?

Although naltrexone is 50 years old, it is unlikely for it to become widely used to treat chronic pain in low doses. In fact, many doctors are unaware of the benefits of LDN for pain management. 

Because the drug is so old, drugmakers lack the incentive to bring LDN to the market in generic form. This leaves many patients with chronic pain turning to compound pharmacies or the internet for pain relief. Some YouTube videos instruct patients to turn a 50 mg tablet into a liquid version with a dose low enough to treat chronic pain. 

Patricia Danzon, professor of healthcare management at the University of Pennsylvania’s Wharton School, says the timeline of bringing a new drug to the market might discourage drugmakers as well. 

“[It] requires getting FDA approval and that requires doing clinical trials,” she said. “That’s a significant investment, and companies—unsurprisingly—are not willing to do that unless they can get a patent and be the sole supplier of that drug for at least some period of time.” 

One drug company, Alkermes, has had huge success manufacturing the only extended release version of the drug, Vivitrol, but has not seen enough evidence that it works to treat chronic pain to start producing the drug in low doses. 

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