The influence of naloxone infusion on the action of intrathecal diamorphine: low-dose naloxone and neuroendocrine responses.

Abstract

The influence of an intravenous infusion of naloxone 1 microgram kg-1 h-1, in combination with intrathecal diamorphine, on analgesia and hormonal stress responses after laminectomy was assessed in a blinded, randomized, placebo-controlled study. Twenty-seven patients undergoing laminectomy with postoperative analgesia provided by intrathecal diamorphine were investigated. Analgesia was reduced by naloxone (P less than 0.05), and the duration of analgesia was shortened by 180 min. The postoperative concentrations of both blood glucose and serum cortisol were reduced in the naloxone group compared to the control group (P less than 0.05). These results may indicate an excitatory role for the hypothalamic mu receptor in hypothalamo-pituitary-adrenocortical axis regulation.