Single-dose ketorolac and pethidine in acute postoperative pain: systematic review with meta-analysis

For a systematic review of postoperative analgesic efficacy and adverse eff ects of single doses, injected or oral, of pethidine and ketorolac compared with placebo, we sought: published randomized-studies in moderate to sever e postoperative pain. Information on summed pain intensity or pain relief o utcomes over 4-6 h was extracted and convened to dichotomous information to produce the number of patients with at least 50% pain relief. This was use d to calculate the relative benefit and number-needed-to-treat (NNT) for on e patient to achieve at least 50% pain relief. Minor and major adverse effe ct data were extracted and summarized. For pethidine 100 mg i.m., eight ran domized, controlled studies met the inclusion criteria, with 203 patients g iven pethidine and 161 placebo. The NNT to produce at least 50% pain relief was 2.9 (95% confidence interval 2.3-3.3). At this dose. pethidine produce d significantly more drowsiness and dizziness than placebo, with numbers-ne eded-to-harm (NNH) of 2.9 (2.2-4.4) and 7.2 (4.8-14), respectively. For ket orolac, 14 reports met the inclusion criteria (six i.m. and eight oral). Mo st i.m, information (176 patients) was available for the 30 mg dose, which had an NNT of 3.4 (2.5-4.9). Most oral information was available for the 10 mg dose, which had an NNT of 2.6 (2.3-3.1). Oral ketorolac 10 mg was consi stently at least as effective as ketorolac 30 mg i.m. Only with oral ketoro lac 10 mg were there significantly more adverse effects than with placebo, with an NNH for any adverse effect of 7.3 (4.7-17).