The safety and efficacy of intrathecal diamorphine.

One hundred and seventy-eight patients undergoing total hip replacement and 67 patients undergoing spinal surgery were given diamorphine intrathecally in varying doses. Doses in mg/kg were plotted against duration of analgesia and the absence of retention and emetic symptoms in each type of surgery. Analysis showed that these were not dose dependent within the therapeutic range of 0.005-0.015 mg/kg.