British medical journal (Clinical research ed.)
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Br Med J (Clin Res Ed) · Jul 1985
Randomized Controlled Trial Clinical TrialRelief of pain by infusion of morphine after operation: does tolerance develop?
To see whether continuous intravenous infusion of opiates provides more effective postoperative relief of pain than conventional intramuscular injection these regimens were compared in a prospective double blind trial. Thirty patients undergoing elective cholecystectomy were allocated randomly to receive an infusion of morphine or an infusion of placebo (control group) for 24 hours. Both groups were allowed supplementary morphine boluses as requested. ⋯ Nausea and vomiting were more prevalent among the patients given the infusion of morphine. These results suggest that continuous infusion of morphine may be an inferior regimen to intermittent bolus administration in the relief of postoperative pain. This may be explained by the development of tolerance in patients who received the infusion of morphine.