title: Sexual dimorphism in very low dose nalbuphine postoperative analgesia.
abstract: In recent studies we demonstrated that the analgesic effect of the kappa-like opioids is significantly greater in women, that low dose nalbuphine (5 mg) produces profound anti-analgesia (i.e. enhances pain) in men, and that addition of a low dose of the non-selective opioid receptor antagonist naloxone (0.4 mg) to nalbuphine (5 mg) abolishes the sex difference and results in significantly enhanced analgesia in both sexes. To further delineate the dose-dependent analgesic and anti-analgesic effects of nalbuphine, the present study evaluated the effect of a lower dose of nalbuphine (2.5 mg), with and without naloxone, on dental postoperative pain. In women, nalbuphine alone induced modest, short duration analgesia, which was antagonized rather than enhanced by the addition of naloxone (0.4 mg). In men, this dose of nalbuphine alone did not produce analgesia or anti-analgesia, and naloxone (0.4 mg) did not alter the response to nalbuphine. Thus, the anti-analgesic effect of nalbuphine, present in both sexes at the 5 mg dose disappears at the lower dose of nalbuphine. In addition, the mild analgesia in women produced by this lower dose of nalbuphine is antagonized by naloxone.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University of California, San Francisco, CA 94143, USA.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Gear
authors.forename: Newton C
authors.initials: NC
authors.lastname: Gordon
authors.forename: Christine
authors.initials: C
authors.lastname: Miaskowski
authors.forename: Steven M
authors.initials: SM
authors.lastname: Paul
authors.forename: Philip H
authors.initials: PH
authors.lastname: Heller
authors.forename: Jon D
authors.initials: JD
authors.lastname: Levine
mesh_terms: D000328:Adult; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D009266:Nalbuphine / Q000008:administration & dosage / Q000627:therapeutic use*; D009270:Naloxone / Q000627:therapeutic use; D010149:Postoperative Pain / Q000188:drug therapy* / Q000209:etiology; D017473:Receptors, Opioid, kappa / Q000187:drug effects; D012737:Sex Factors; D014081:Tooth Extraction / Q000009:adverse effects
chemical_list: D000701:Analgesics, Opioid; D017473:Receptors, Opioid, kappa; D009270:Naloxone; D009266:Nalbuphine