Background: Rectal administration of morphine is one possible route of delivery in children. The aim of this study was to determine the pain experience during rectal administration of two different morphine preparations.
Methods: The acceptance of the pain of rectal administration of morphine for premedication was studied in 120 children. Children were randomized to receive either morphine solution in saline (0.2 mg.kg(-1), 1 mg.ml(-1)) or morphine gel (0.2 mg.kg(-1), 1 mg.ml(-1)) with an adjusted pH for rectal use in a double-blind fashion. Children were stratified into three groups according to age (1-2, 3-6, and 7-10 years). Pain was assessed with the Children's Hospital of Eastern Ontario Pain Scale, the McGrath Facial Affective Scale, or the visual analogue scale, depending on the age group.
Results: The overall pain scores in all age groups were low. Children aged 1-2 years (P < 0.01) and 3-6 years (P < 0.05) had significantly less pain when morphine was administered as a gel than a solution. The difference in pain experience between the two forms was not significant in the age group of 7-10 years.
Conclusion: The results indicate that most of the children tolerated rectal administration of morphine well in terms of pain experience, in both gel and solution form. The morphine gel, intended for rectal use appears to be the preparation of choice in children aged 1-6 years.