A randomised, double-blind placebo controlled study was undertaken to assess the analgesic efficacy of diclofenac. Following major abdominal surgery and 12 hours later. patients received either placebo or diclofenac 75 mg intramuscularlj~ and their cumulative morphine requirements administered by a patient-controlled system over 24 hours were compared. Pain scores were also measured. Arterial blood gases and cougulation studies were assessed pre-and postoperatively. Morphine consumption was significantly greater in the placebo group (59.5 compared to 38.5 mg, p < 0.01). Pain scores were significantly lower in the diclofenac group at 4 hours, but not thereafter. Arterial carbon dioxide was signijcantly increased in the control groups. There was no significant change in platelet count within each group, but a signijcant difference between the groups (p < 0.05).
Key wordsAnalgesics, narcotic; morphine.
Analgesics. non-narcotic; diclofenacThe effective management of postoperative pain remains a problem for the anaesthetist and surgeon. Many patients experience severe pain using the conventional regimen of intermittent intramuscular opioids.' ,z This may be caused by factors such as fear of respiratory depression or addiction with on-demand regimens, which results in irregular administration, fluctuating plasma concentrations and inadequate relief of pain. Furthermore, many patients will not request analgesia unless specifically asked if they are in pain and, in addition, the delay between request and effective plasma concentrations may be as long as 1 hour.3Recent studies have suggested that the addition of non-steroidal anti-inflammatory drugs may reduce opioid requirements, improve pain relief and reduce respiratory d e p r e s~i o n .~,~ Diclofenac is a phenylacetic acid derivative with significant analgesic, anti-inflammatory and antipyretic properties. It is a member of the prostaglandin synthetase inhibitor group of drugs and is available in parenteral form Baroni and his colleagues have demonstrated that diclofenac has an analgesic effect within 30 minutes in 80% of patients when used for postoperative pain relief; in 83% of cases the analgesic effect lasted for more than 4 hours. It has been shown to provide effective pain relief in inflammatory joint disease, renal colic and, more recently, in the control of pain following hip surg e~-~.~,~The aim of this study was to assess the analgesic efficacy of intramuscular diclofenac following major abdominal surgery.
Metho&Patients scheduled to undergo abdominal surgery between the ages of 18-75 years and weight 40-95 kg, were considered eligible for inclusion in this study. Those with manifest respiratory, cardiac, hepatic or renal insufficiency. a history of haemorrhagic diathesis, haematemesis or anticoagulant therapy, or allergy to aspirin. diclofenac or other prostaglandin-inhibiting compounds, were not studied. Patients who had a history of peptic ulceration and were not scheduled to undergo corrective surgery, were also excluded. The study was approved by th...