Life is pain, and sometimes, alas, it's not metaphorical at all. Some patients have to fight a constant and almost hopeless struggle with it. To do this, any means are used, even such dangerous ones as opioid analgesics, known for a lot of side effects. But in recent years, scientists and doctors are getting closer to radically changing the nature of these analgesics, canceling their negative effect, but preserving the analgesic.