TOPICS: Opioid analgesics, agonist, mu receptor, beta endorphin, delta receptor, enkephalin, kappa receptor, dynorphin, close presynaptic calcium channels, open postsynaptic potassium channels, decreased pain transmission, inhibits ACh release, substance P, NE, 5-HT, glutamate, full opioid agonists, morphine, heroin, meperidine, verapamil, gingival hyperplasia, methadone, maintenance programs for heroin addicts, moderate to severe pain, refractory pain, acute pulmonary edema, nausea, vomiting, pruritus, histamine release, cautiously in patients with hypotension, addiction possible, respiratory depression, constipation, slows gut motility, no tolerance against constipation, sphincter of Oddi spasm, biliary colic, miosis, no tolerance against miosis, meperidine causes mydriasis, additive CNS depression, naloxone, naltrexone
