Opioid Use for Pain Management
"'Opioid' is a generic term for natural or synthetic substances that bind to specific opioid receptors in the CNS, producing an agonist action. Opioids are also called narcotics—a term originally used to refer to any psychoactive substance that induces sleep. Opioids have both analgesic and sleep-inducing effects, but the 2 effects are distinct from each other.
"Some opioids used for analgesia have both agonist and antagonist actions. Potential for abuse among those with a known history of abuse or addiction may be lower with agonist-antagonists than with pure agonists, but agonist-antagonist drugs have a ceiling effect for analgesia and induce a withdrawal syndrome in patients already physically dependent on opioids.
"In general, acute pain is best treated with short-acting pure agonist drugs, and chronic pain, when treated with opioids, should be treated with long-acting opioids (see Table: Opioid Analgesicsand Equianalgesic Doses of Opioid Analgesics*). Because of the higher doses in many long-acting formulations, these drugs have a higher risk of serious adverse effects (eg, death due to respiratory depression) in opioid-naive patients."
"Treatment of Pain." The Merck Manual for Health Professionals. Merck & Co. Inc. Last accessed November 1, 2017.