Inclusion of pethidine in lidocaine for infiltration improves analgesia following tonsillectomy in children

Background: Previous work has demonstrated that pethidine exerts local anaesthetic effects on peripheral nerves in vivo. We examined the effects of infiltration anaesthesia by a combination of pethidine and lidocaine on post-tonsillectomy pain and restlessness in children. Methods: Eighty children were randomly allocated to receive peritonsillar infiltration postoperatively with 3 ml of lidocaine 2% (1.5 ml on each side) combined with either 0.1 ml pethidine, 10 mg · ml-1, (pethidine group) or 0.1 ml normal saline (control group). Pain and behaviour were assessed at 1, 3, 6 and 12 h postoperatively and on the following morning by the patients and by a nurse blinded to previous treatment. Results: Patients in the pethidine group had lower pain scores than those in the control group at rest as well as swallowing during the whole observation period (P<0.05). Paracetamol was given to 34/40 children in the control group and to 6/40 children in the pethidine group. The corresponding figures for pethidine administration were 6/40 and 0/40, respectively. Patients in the pethidine group displayed a more rapid return to calm wakefulness than those in the control group (P<0.01). Conclusion: Inclusion of a low dose of pethidine in lidocaine for tonsillar infiltration improves pain relief after tonsillectomy in children.