In a parallel single-blinded randomized clinical trial , ninety @-@ y-old uncooperative kids who were referred to Pediatric Neurology Clinic of Shahid Sadoughi University , Yazd , Iran from April through August @ , were randomly assigned to receive @mg/kg of chloral hydrate or @mg/kg of chloral hydrate and @mg/kg of promethazine or @mg/kg of chloral hydrate and @mg/kg of hydroxyzine .