DOSE-EFFECT RELATIONSHIPS OF EXTRADURAL MORPHINE

The effectiveness of three different doses of extradural morphine(4,6 and 8 mg) in relieving post-operative pain was comparedin 24 patients. Although there was no significant differencein the efficacy of the three doses, increasing dosage increasedthe average duration of analgesia provided by the drug (4 mg–593min; 6 mg–722 min; 8 mg–885 min). All three dosesincreased the average peak expiratory flow rate, the greatestincreases bang seen at the higher dosages. Increasing dosagewas not accompanied by an increase in the occurrence of adverseeffects.