The Effects of Naloxone and Nalorphine during the Development of Morphine Dependence in Rhesus Monkeys

Authors:
  • MAM D Aceto
    M D Aceto
  • RFR.E. Flora
    R.E. Flora
  • LHL.S. Harris
    L.S. Harris
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Abstract
A randomized and blind experimental design was used to study the effects of naloxone and nalorphine on the development of morphine dependence in monkeys. The results suggest: (a) that significant dose-related differences existed for combined numbers of withdrawal symptoms times frequency of occurrences; (b) that naloxone and nalorphine were qualitatively similar; (c) antagonists are more effective as dependence develops; (d) naloxone is approximately 10 times more potent than nalorphine, and (e) vomiting was the only withdrawal sign with which EDsos could be calculated. Dependence on morphine still increases up to 9 months after the commonly accepted 90-day stabilization period as measured by the ED50 for vomiting for naloxone.