Morphine Depression of Ventilatory Response to Hypoxia, and Reversal by Naloxone.

摘要

Ventilatory response to 'isocapnic' hypoxia was measured in awake beagle dogs prior to and following administration of intravenous morphine sulfate, 0.6 mg/kg. Hypoxic ventilation was depressed within 30 minutes, was maximally depressed at one to two hours, and remained depressed for at least six to seven hours following the administration of morphine. Naloxone, 0.4 mg IV, completely reversed the morphine depression of the ventilatory response to hypoxia, but only transiently; 30 to 45 minutes after naloxone reversal, the ventilatory respone to hypoxia was again significantly depressed. Naloxone alone demonstrated mild agonist properties on the ventilatory response to hypoxia, but the effect varied among the dogs. (Author)