This study will be a randomized double blind placebo controlled clinical trial among children undergoing adeno-tonsillectomy in KNH. The intervention arm will comprise Fentanyl given at a dose of 1ug/while the placebo arm will be given normal saline at a volume equivalent to Fentanyl dose, treatment will be administered approximately ten minutes to the end of surgery determined by the time when the mouth gag will be removed. The main outcome will be incidence of ED at the recovery room using Watcha scale and secondary outcomes will be delay in emergence time from anaesthesia and effectiveness of fentanyl in preventing ED.