New concepts in the action of analgesic drugs.
D000700:Analgesics; D006801:Humans; D009020:Morphine / Q000494:pharmacology*; D009269:Nalorphine / Q000494:pharmacology*
D000700:Analgesics; D009020:Morphine; D009269:Nalorphine
MORPHINE/effects; NALORPHINE/effects