This randomized controlled study at Zagazig University Hospitals will include 112 patients undergoing elective functional endoscopic sinus surgery, allocated into four groups (Melatonin, Metoprolol, Dexmedetomidine, Control). Preoperatively, patients will provide consent, undergo history, clinical and airway assessment, baseline vitals, laboratory tests, and serum cortisol and glucose measurement. Intraoperatively, standard monitoring will be applied, and study drugs administered according to group. Anesthesia will be induced with propofol, fentanyl, and atracurium, and maintained with isoflurane and controlled ventilation. Hemodynamics will be continuously monitored, and surgical field graded using ACS score, with interventions for hypotension, bradycardia, or tachycardia as needed. Postoperatively, emergence agitation, hemodynamics, and drug-related side effects will be recorded, and surgeon satisfaction assessed with a 5-point Likert scale.

Inclusion Criteria:

1. Patient acceptance.
2. Age: 21-60 years old.
3. Body mass index (BMI): 18-30 kg/m2. 8
4. Sex: both sexes (male and female).
5. Physical status: American Society of Anesthesiologists (ASA) physical status I and II.
6. Type of operation: elective functioning endoscopic sinus surgery.
7. Duration of surgery: average 2 hours.

Exclusion Criteria:

1. Hypertension and those on beta blockers and calcium channel blockers.
2. Diabetes mellitus and bronchial asthma.
3. Cardiac arrhythmias, atrio-ventricular conduction block, pulse less than 60 beats/min systolic blood pressure less than 100 mm hg.
4. Patients with anticipated difficult intubation (Mallampati score III and IV).
5. Psychiatric illness, intake of antipsychotics, sedatives, anxiolytics and antiepileptic drug.
6. The pregnant and lactating females.
7. Allergy to one of the used drugs.
8. Patient with coagulation disorders.