Morphine consumption in patients receiving rectal paracetamol and diclofenac alone and in combination

Paracetamol and diclofenac have different mechanisms of action, and the combination may be more effective than each drug used alone in treating postoperative pain. In a double-blind, controlled design, we studied 60 patients undergoing elective abdominal gynaecological surgery, who received suppositories of paracetamol 1.5 g, diclofenac 100 mg or a combination of the two before the start of surgery. Patients received morphine in the intraoperative period, and cumulative morphine use from a patient-controlled analgesia system was recorded to measure the analgesic effect of the suppositories. Morphine consumption was greatest in the group that received paracetamol alone and lowest in the group given the combination (P<0.01). There was no difference in the incidence of morphine-related side effects between the groups. We conclude that a diclofenac-paracetamol combination reduced the amount of morphine used compared with paracetamol alone.