Basics of opioid analgesic pharmacodynamics.
D000698:Analgesia; D000701:Analgesics, Opioid / Q000378:metabolism* / Q000627:therapeutic use; D004361:Drug Tolerance; D006801:Humans; D011957:Receptors, Opioid / Q000502:physiology*; D019966:Substance-Related Disorders
D000701:Analgesics, Opioid; D011957:Receptors, Opioid