title: Enhanced analgesia and suppression of plasma beta-endorphin by the S(+)-isomer of ibuprofen.
abstract: BACKGROUND
  Peripheral nociceptive barrage after tissue injury results in acute pain and a variety of physiologic responses, including pituitary secretion of beta-endorphin. This study evaluated whether administration of the pharmacologically active S(+)-isomer of ibuprofen suppresses acute pain and plasma beta-endorphin levels in the oral surgery model of acute pain.
  
  
  METHODS
  Subjects in a single-dose, double-blind, parallel-group study received either 200 mg S(+)-ibuprofen, 400 mg S(+)-ibuprofen, 400 mg racemic ibuprofen, or placebo. Both doses of S(+)-ibuprofen resulted in significantly greater analgesia over the first 60 minutes in comparison to racemic ibuprofen and placebo; the 400 mg dose of S(+)-ibuprofen also produced greater analgesia at 2 and 3 hours. Plasma levels of immunoreactive beta-endorphin decreased over time coincident with the onset of analgesia in all groups but were significantly less than placebo after both doses of S(+)-ibuprofen from 30 to 120 minutes.
  
  
  CONCLUSIONS
  These findings show that, compared with racemic ibuprofen, administration of the S(+)-isomer of ibuprofen results in faster analgesic onset, greater peak analgesia, similar duration of action, and a low incidence of adverse effects, while suppressing nociceptive activation of the pituitary-adrenal axis.
authors.affiliation: National Institute of Dental Research, Nursing Department, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: R A
authors.initials: RA
authors.lastname: Dionne
authors.forename: L
authors.initials: L
authors.lastname: McCullagh
mesh_terms: D000328:Adult; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007052:Ibuprofen / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D007536:Isomerism; D008297:Male; D019647:Oral Surgical Procedures / Q000009:adverse effects; D010147:Pain Measurement; D010149:Postoperative Pain / Q000097:blood / Q000188:drug therapy* / Q000209:etiology; D013997:Time Factors; D016896:Treatment Outcome; D001615:beta-Endorphin / Q000097:blood* / Q000187:drug effects*
chemical_list: D018712:Analgesics, Non-Narcotic; D001615:beta-Endorphin; D007052:Ibuprofen