A randomised controlled trial of parecoxib, celecoxib and paracetamol as adjuncts to patient-controlled epidural analgesia after caesarean delivery.

The benefit of combining non-opioid analgesics with neuraxial opioids for analgesia after caesarean delivery has not been clearly established. Larger doses of paracetamol or cyclooxygenase-2 inhibitors have not been evaluated. A randomised, double blind, double-dummy, parallel group placebo-controlled clinical trial was conducted among women having elective caesarean delivery under spinal anaesthesia, followed by pethidine patient-controlled epidural analgesia. Patients received placebos (group C); intravenous parecoxib 40 mg then oral celecoxib 400 mg at 12 hours (group PC); intravenous paracetamol 2 g then oral 1 g six-hourly (group PA); or these regimens combined (group PCPA). The primary outcome was 24-hour postoperative patient-controlled epidural pethidine use and the main secondary outcome was postoperative pain. One hundred and thirty-eight women were recruited but 27 subsequently met exclusion criteria, leaving 111 who were randomised, allocated and analysed by intention-to-treat (n=23, 30, 32 and 26 in groups C, PC, PA and PCPA respectively). There were no differences between groups for pethidine consumption, based on either intention-to-treat (median 365, 365, 405 and 360 mg in groups C, PC, PA and PCPA respectively, P=0.84) or per protocol analysis (17 major violations). Dynamic pain scores did not differ between groups but requirement for, and dose of, supplementary oral tramadol was least in group PCPA (incidence 23% versus 48%, 70% and 58% in groups C, PC and PA respectively, P=0.004). The addition of regular paracetamol, cyclooxygenase-2 inhibitors or both to pethidine patient-controlled epidural post-caesarean analgesia did not provide a pethidine dose-sparing effect during the first 24 hours.