EFFECTIVE DOSE OF RECTAL ACETAMINOPHEN FOR IMMEDIATE POSTOPERATIVE PAIN RELIEF IN PAEDIATRIC DAY-CASE INGUINAL SURGERY

Abstract

Postoperative pain is a major problem in paediatric day-case surgical procedures worldwide. The side effects of opioid analgesics and non-steroidal anti-inflammatory drugs in paediatric surgical patients have limited their use. The recent withdrawal of dipyrone from Nigeria drug formulary has made the search for an alternative drug that can be used perioperatively in paediatric day-case surgical procedures of paramount importance.
The aim of this study was to determine the effective dose of rectal acetaminophen for immediate postoperative pain relief in paediatric day-case inguinal surgery. The study was a randomized double blind trial of one hundred and five paediatric patients between the ages of one and seven years who had day-case inguinal surgical procedures. Patients were randomized to receive a single dose of either approximately 20, 40 or 60mg/kg of rectal acetaminophen after induction of general anaesthesia. General anaesthesia was induced and maintained with inhaled halothane, nitrous oxide and oxygen. Opioids and local anaesthetics were not used.
Postoperative pain was evaluated every ten minutes in recovery room by the use of Children’s Hospital of Eastern Ontario Behavioural Pain Scale (CHEOPS). The need for rescue analgesic, I.V Pentazocine 0.1mg/kg was decided by the researcher who was unaware of the dose of rectal acetaminophen administered. The parents were interviewed by phone after 24hrs regarding the quality of pain relief, nausea and vomiting. Postoperative analgesic at home was oral Paracetamol (10 -15 mg/kg) every 6 hours.
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In the recovery room, pain scores were significantly lower in the 40- and 60mg/kg rectal acetaminophen groups compared with 20mg/kg group. Rectal acetaminophen had a clear dose-dependent analgesic effect in children, post day-case inguinal surgical procedures, with significance reached with 40 and 60mg/kg dose.
The need for rescue analgesic at home during the first 24hrs after surgery was also significantly less in 40 and 60mg/kg groups compared with 20mg/kg group. None of the one hundred and five patients studied vomited in recovery room. However, two (5.7%) patients in 20mg/kg group vomited at home while none in 40 and 60mg/kg group had emetic complication.
In conclusion, a single dose of 40 or 60mg/kg of rectal acetaminophen has a clear dose-dependent analgesic effect in children undergoing day-case inguinal surgical procedures.