Intravenous Magnesium Sulphate Versus Dexmedetomidine for Prevention of Emergence Agitation in Adult Otorhinolaryngologic Surgery

The goal of this clinical trial is to learn whether intravenous magnesium sulphate can reduce emergence agitation as effectively as intravenous dexmedetomidine in adult patients undergoing otorhinolaryngology surgery under general anesthesia. The main questions it aims to answer are: \- Is intravenous magnesium sulphate non-inferior to intravenous - dexmedetomidine in reducing the proportion of emergence agitation (defined as Richmond Agitation-Sedation Scale \[RASS\] ≥2)? Are there differences between the two drugs in terms of hemodynamic stability, severity, onset and duration of emergence agitation, and recovery profile? Researchers will compare continuous intravenous magnesium sulphate infusion (20 mg/kg/hour) with continuous intravenous dexmedetomidine infusion (0.5 µg/kg/hour) to see if magnesium sulphate provides similar protection against emergence agitation with fewer hemodynamic side effects. Participants will: * Be randomized to receive either magnesium sulphate or dexmedetomidine infusion from induction of anesthesia until the end of surgery. * Undergo standardized general anesthesia with sevoflurane, fentanyl, and rocuronium. * Be assessed for emergence agitation using the Richmond Agitation-Sedation Scale (RASS) after discontinuation of anesthetic agents. * Have intraoperative heart rate, mean arterial pressure, anesthetic consumption, and vasoactive drug use recorded. * Be evaluated postoperatively for pain, opioid requirement, and extubation time.