Study designs of evaluations included in the review
Randomised placebo controlled trials of blinded design were included if they were full journal publications and reported data from which TOTPAR, SSPID, VASTOTPAR OR VASSPID could be calculated.
Specific interventions included in the review
Single doses of placebo were compared with single doses of morphine given intramuscularly or intravenously in doses of 5 mg, 8 mg, 10 mg, 12.5 mg and 20 mg.
Participants included in the review
Adult patients experiencing non-surgical pain (due to acute trauma) or undergoing the following types of surgery with baseline pain of moderate to severe intensity were included: general; gynaecological; orthopaedic surgery including hip and knee replacements; third molar extraction; and day surgery.
Outcomes assessed in the review
Pain intensity or pain relief over 4 to 6 hours post operatively and adverse reactions were assessed. Outcome measures included total pain relief (TOTPAR), summed pain intensity difference (SPID) and visual analogue equivalents (VASTOTPAR, VASSPID).
How were decisions on the relevance of primary studies made?
Each report that could possibly be described as a randomised controlled trial was read independently by the three authors and consensus was achieved.