Summary: Naltrexone, a drug used to treat substance abuse, works well for intractable (hard-to-treat) pain at a low dose. Low-dose naltrexone (LDN) works even better alongside other drugs, like anti-inflammatories and nerve pain drugs. But it should not be taken with opioids, because of the risk of severe side effects or drug interactions. Intractable pain is one of the hardest pain problems to treat. Doctors often have to prescribe opioids for it. But opioids cause many side effects.
Of all chronic pains, none is harder to treat than intractable pain. As the name suggests, it is not just pain. It is a condition that regular painkillers struggle to treat. People with intractable pain keep hurting even after the problem that first caused the pain has been cured. Doctors do not fully understand why. But they think it comes from inflammation in the nerves, spine, and brain, and changes in certain brain centers.
So intractable pain needs a very different approach from pain with other causes, like low back pain, arthritis, or rheumatic conditions. But very few options exist today that give enough relief. That is why some US states now see intractable pain as its own health problem. They treat it as separate from chronic pain, and as a condition that justifies long-term opioid therapy.
But the problems with long-term opioid use are no secret. First, people get addicted to these drugs. These drugs also cause hyperalgesia (more sensitivity to pain). So people need higher doses over time, which raises the risk of side effects even more. Now researchers seem to have found a new way to manage intractable pain. Low-dose naltrexone (LDN) is one of the new therapies for intractable and chronic pain.
Naltrexone is an old, well-known drug used to treat substance abuse. It also treats opioid abuse and can even reverse some side effects of opioids. Now researchers have found that at lower doses, it can be an excellent painkiller. It also helps calm inflammation in the spine and brain and can even boost immunity.
LDN’s excellent safety record supports its use for intractable pain. Its clinical safety is well proven. The only limit is that it should not be used with opioids. It would weaken the opioids and may cause unpleasant interactions with them.
Doctors usually use 0.5 to 1 milligrams of Naltrexone twice daily for intractable pain. LDN may help intractable pain without the need for opioids. LDN seems to work well with other drugs, like gabapentin for nerve pain, Adderall, Mucuna, and others. Doctors may also suggest low-dose naltrexone (LDN) for pain relief along with standard anti-inflammatory drugs like ketorolac.
LDN can get strong results in complex regional pain syndrome (CRPS) treatment and sciatica nerve pain relief. LDN seems to help most when used steadily over a long time, along with other less toxic painkillers. Unlike other drugs, LDN can tune down intractable pain by changing immune responses and calming inflammation in the nerves. So over time, it may help intractable pain go away completely.
As noted, LDN should not be used with opioids, because it can interact with them in unpleasant ways. But doctors may use low-dose man-made opioids during pain flares. Long-term use with high-dose opioids is not advised because of the risk of severe side effects. People taking opioids can also be switched to LDN. But they would first need to stop the opioids. Studies show some patients may get very sick if they take LDN while on opioids.
Researchers say that if opioids already give a person good pain relief, there is no reason to switch to LDN.
Frequently asked questions
Can naltrexone be used for pain?
Yes, at a low dose. Naltrexone is an old drug for substance abuse. But at low doses it works as a painkiller and calms inflammation in the spine and brain. Doctors use it because its clinical safety is well proven. It gives people with intractable pain an option that does not depend on opioids.
What kind of pain does low-dose naltrexone help?
Its main target is intractable pain. That is pain that keeps going after the first injury or illness has healed, and that normal painkillers do not touch. Doctors tie that pain to inflammation in the nerves and spine and to changes in brain centers. LDN works by calming that inflammation. It can get strong results in complex regional pain syndrome (CRPS) and sciatica nerve pain, especially when taken steadily over a long time.
Can you take low-dose naltrexone with opioid painkillers?
No. Naltrexone weakens opioids, and taking the two together can cause unpleasant interactions. Some patients get very sick. A patient on opioids can be switched to LDN, but the opioids have to be stopped first. If opioids already give you good relief, researchers see no reason to switch.
Can low-dose naltrexone be combined with other pain medications?
Yes, and it often works better that way. LDN pairs well with gabapentin for nerve pain and with standard anti-inflammatory drugs such as ketorolac. It is meant to be used long term alongside these less toxic painkillers, not opioids. Your physician picks the mix based on your type of pain and the drugs you already take.
Dr. Gurpreet Singh Padda, MD, MBA, MHP
