(1) Aim: Determination and comparison of oral Promethazine's effect, oral Midazolam and Placebo on preoperative anxiety, pulse rate, blood pressure, respiratory rate, nausea and vomiting in referred children (3-8 years old) to Khorramabad Shohadaye Ashayer Hospital.
(2) Design: Randomized / Double blind / Controlled with Placebo / Single center.
(3) Setting and conduct: Sampling method is based on inclusion criteria. Children are categorized into one of the three groups (Promethazine, Midazolam and Placebo) based on simple randomized allocation. Then interventions are done on them and results are recorded in questionnaire.
(4) Participants, Inclusion and exclusion criteria: Sample volume is 123. Inclusion criteria: Children with 3-8 years old / With American Society of Anaesthesiologists (ASA) grade 1 and 2 / under general anaesthesia / elective surgery / lack of chronic disease, prematurity, growth retardation, brain disorders, vision and acoustic disorders / with a written consent form from parents.
Exclusion criteria: History of allergy to used drugs in this study / Children with emergency surgery.
(5) Interventions: Interventions include three groups (Promethazine, Midazolam and Placebo) and are done 2 hours before surgery.
(6) Primary outcome measure: Preoperative anxiety by Yale Preoperative Anxiety Scoring (YPAS)