The document discusses several opioid drugs including morphine, codeine, meperidine, diphenoxylate, loperamide, fentanyl, methadone, propoxyphene, pentazocine, and levorphanol. It describes the mechanism of action and uses of each drug. The drugs derive analgesic effects through binding to opioid receptors in the brain and body and are used medically to treat pain or induce anesthesia. The document provides information on opioid drugs and their clinical applications.