Analgesia after caesarean section with intramuscular ketorolac or pethidine

We compared, in a double-blind randomised study, intramuscular ketorolac 30 mg (n = 49) and intramuscular pethidine 75 mg (n = 51) for analgesia after elective caesarean section under general anaesthesia. Anaesthesia was induced with thiopentone and suxamethonium and maintained with atracurium, nitrous oxide and isoflurane. Intravenous fentanyl 100 micrograms was given after delivery of the neonate. In the recovery ward, patients who requested analgesia were allocated randomly to receive ketorolac 30 mg or pethidine 75 mg intramuscularly. Analgesia was assessed at intervals up to six hours, using a visual analogue scale and a four-point verbal scale, while duration of analgesia was taken as the time until the patient requested additional analgesia. There was no difference in the duration of analgesia between groups (Mann-Whitney test P = 0.27, Mantel-Haentszel test P = 0.17). Twenty-six patients in the ketorolac group and 17 patients in the pethidine group requested further analgesia by 90 minutes. However, four patients in the ketorolac group and six patients in the pethidine group requested no further analgesia within 24 hours. Pain VAS and overall assessment of analgesia was similar between groups, although more side-effects (nausea, dizziness) were noted in the pethidine group. Ketorolac 30 mg and pethidine 75 mg provided similar but variable quality of analgesia after caesarean section.