Inclusion Criteria:  Children physical status according to the American Society of Anesthesiologists I and II Submitted to general anesthesia to perform tonsillectomy associated or not with adenoidectomy  Exclusion Criteria:  Refusal to participate in the study Presence of kidney, liver or neuromuscular disease Contraindication to the use of any drug used in the study Body mass index (BMI) ≥ 30.