IRCT201310218768N2 IRCT 2014-05-20 vice chancellor for research of Tehran university of medical science The effect of paracetamol on post operative pain, nausea and vomiting after strabismus surgery Evaluation the effect of intravenous paracetamol on post operative pain and nausea and vomiting in pediatric patients undergoing strabismus surgery 2013-12-01 anticipated 120 Complete https://irct.ir/trial/9257 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Factorial, Purpose: Treatment. N/A Condition 1: acute postoperative pain. Condition 2: nausea and vomiting. Intervention 1: control group: Intravenous infusion of normal saline(1.5ml/kg) in 20 minutes at the end of surgery. Two or more vomiting episodes will be treated with ondansetrone 0. 1mg/kg. The Facial Pain Scale will be used to measure postoperative pain after surgery and if the pain score to be measured is 3 or more, the patient will receive acetaminophen with a dose of 10mg/kg. Nausea and vomiting and pain score will be assessed in post-anesthesia care unit and in ward in 6-12 and 24 hours after surgery. Intervention 2: Intervention group: Intravenous infusion of paracetamol 15mg/kg (1.5ml/kg of 1 gram paracetamol in 100 cc normal saline) in 20 minutes at the end of surgery. Two or more vomiting episodes will be treated with ondansetrone 0. 1mg/kg. The Facial Pain Scale will be used to measure postoperative pain after surgery and if the pain score to be measured is 3 or more, the patient will receive acetaminophen with a dose of 10mg/kg. Nausea and vomiting and pain score will be assessed in post-anesthesia care unit and in ward in 6-12 and 24 hours after surgery.