evaluation of a low dose ketamine in post tonsillectomy pain relief: a randomized trial comparing intravenous and subcutaneous ketamine in pediatrics

background pain control in children is still a therapeutic dilemma. preschool patients are affected from undesirable effects of postoperative pain more than adults. tonsillectomy is associated with a high incidence of postoperative pain, not only complicating the recovery, but also delaying patients discharge. objectives despite employing different surgical and anesthetic strategies in post-tonsillectomy pain relief, this is still a clinical problem. the study was designed to evaluate the efficacy of a low dose ketamine in post tonsillectomy pain relief. patients and methods our prospective randomized double blinded study enrolled 75 pediatric patients (3-10 years old) who were scheduled for a tonsillectomy procedure. patients were randomly assigned to one of three groups receiving; intravenous (iv) ketamine 0.5mg/kg, subcutaneous (sc) ketamine 0.5 mg/kg and placebo at the end of the operation. post-operative pain score was assessed using modified cheops. results in our study we did not find any significant difference among the three groups regarding sex, age, and weight, duration of operation, hemodynamic stability, and nausea and vomiting. however, in ketamine groups, pain score and analgesic consumption were significantly lower (p < 0.00). the efficacy of the both ketamine groups was similar. conclusions the study demonstrated that the both subcutaneous and intravenous injections of ketamine, at the end of the operation, were safe and effective for post-tonsillectomy pain control. ketamine reduced postoperative analgesic medications consumption without increasing the risk of complications.