Whenever we confront the problem of opioid addiction, the response is to restrict their use in one way or another. However, opioids are currently the world's best pain relievers. Restricting their use hurts patients who deal with severe or chronic pain from conditions that cannot be immediately fixed. At the same time, offering opioids to relieve the pain often turns the patient into an addict. Short of finding a better pain reliever, the best option science can offer is to turn opioids into something non-addictive. And scientists are working on that.
Many of the addictive qualities of opioids are due to the feelings of calm and euphoria they induce in the brain. For conditions like arthritis and wound and postoperative pain, however, these drugs need to target only the diseased or injured areas of the body to provide pain relief. The question researchers face is whether it’s possible to limit the effect of opioids to specific areas of the body without affecting the brain.
One recently proposed solution focuses on the acidity difference between injured and healthy tissue. Injured tissue is more acidic than healthy tissue due to a process known as acidosis, where lactic acid and other acidic byproducts produced by damaged tissue collect. This means that an opioid could potentially be altered to be positively charged and active only in injured tissue, while staying neutral and inactive in normal tissue. The drug would be biochemically active only at a higher acidity level than found in healthy tissue.