This article explains how Ultra Low Dose Naltrexone (ULDN) can be used with opioids to improve the pain relief effect provided by the opioids and avoid the increase in pain that is usually associated with long term use. "Ultra-low-dose naltrexone seems to help block the activation of glial cells caused by long term opioid use, and prevent the amplification of pain that can be induced by long-term opiate use. At very low doses it can do this without blocking the pain-relieving actions of the opiates. The key is finding the dosage sweet spot where LDN is able to calm the glial cells, but not knock the opiates off their receptors. That sweet spot seems to be around 0.5–1mg, called ultra-low-dose naltrexone (usual low-dose naltrexone is 3–4.5mg)." For those who deal with pain this might be a useful treatment to look into.