This is a randomized, double blind, placebo-controlled trial to study the effect of a preoperative oral dose of gabapentin on postoperative analgesic requirements and subjective pain levels in children undergoing tonsillectomy with adenoidectomy. Investigators will also look for a limited set of genotypic variations to explain any difference between individuals or groups in their response to the medication. Additionally, investigators will document potential adverse effects including excessive sedation, respiratory issues, surgical bleeding and emergence agitation/delirium.