The goal of this clinical trial is to compare between the effect of nebulized dexmedetomidine and the effect of oral dispensable film (ODF) melatonin in controlling perioperative anxiety and post operative emergence agitation and their effect on the overall surgical experience.in pediatric patients undergoing day case surgery.

All patients will be admitted on the day of the surgery and will be instructed to fast 6 hours before surgery for older patients, as for breast fed patients, they will be instructed for 4 hours for breast feeding and for formula fed patients they will be instructed to fast for 6 hours as recommended by the American society of anesthesiologists. Preoperative assessment will be done before surgery by one of the members of the team who will make sure that the inclusion and exclusion criteria of the patients are considered, and baseline vital signs will be recorded. According to randomization that will be done by envelop concealed allocation , the drug will be administered to the patients by a researcher who will not participate in the evaluation of the patients 30 mins before transfer to the operation room (OR): each group will receive the intervention drug Parents are not allowed to accompany their children to the OR according to the hospital policy. On arrival to the OR department the Parental separation anxiety scale (PSAS) will be calculated on entering the operation room standard monitoring will be commenced including ECG, non-invasive blood pressure and pulse oximetry and baseline measurement will be recorded. Inhalational induction will be then started with sevoflurane and mask acceptance will be calculated according to the mask acceptance scale (MAS) intravenous cannulation will be then established after which each patient will receive 1-2 mg/kg Propofol, 1 µg/kg fentanyl to attenuate the stress of intubation and 0.5mg/kg atracurium after tracheal intubation anesthesia will be maintained with sevoflurane 2-4 MAC During the length of the operation vital data will be recorded at 5 minutes interval. all patients will receive IV paracetamol 15mg/kg and patient would receive 1 µg/kg fentanyl as a rescue dose if vital data increased by >20% of the baseline.

after the completion of surgery extubating will be performed after meeting extubation criteria and patient will be discharged to post-anesthesia care unit (PACU) in for the first 15 min after admission to PACU the post anesthesia emergence agitation will be assessed by using Pediatric Anesthesia Emergence Delirium Scale (PAED) during the stay in PACU pain will also be assessed by using FLACC score Discharge from PACU will be done after meeting discharge criteria and the time of discharge will be documented. After discharge pain score will be measured using FLACC score at 15, 30, 60 minutes interval postoperative and the total combustion of postoperative analgesics will be calculated as well as the time of discharge from the hospital

Inclusion Criteria:

• Patients of American Society of Anesthesiologists (ASA) physical status I & II
• both genders,
• ≥ 2 to 10 years,
• scheduled for elective day case surgery under general anesthesia

Exclusion Criteria:

• parents' refusal for participation in the study
• ASA III and VI patients with history of chronic illness
• runny nose or upper respiratory tract infection
• Emergency surgeries with hemodynamic instability
• history of allergic reaction to dexmedetomidine or melatonin
• History of prematurity
• developmental delay
• central nervous system disorder,
• mental retardation,
• neurological or psychiatric illness that may be associated with anxiety and agitation (cerebral palsy, seizure, separation anxiety disorder, ADHD etc.).
• treatment with anticonvulsants and sedatives