Impact of Preemptive Analgesia on Postoperative Pain in Orthognathic Surgery

Inclusion Criteria: * Adults aged 21 to 65 years. * American Society of Anesthesiologists (ASA) physical status I or II. * Scheduled to undergo orthognathic surgery including bilateral sagittal split osteotomy and Le Fort I osteotomy under general anesthesia. * Ability to understand the study procedures and provide written informed consent. Exclusion Criteria: * Pregnancy or breastfeeding. * Known allergy or intolerance to acetaminophen, ibuprofen, or other nonsteroidal anti-inflammatory drugs (NSAIDs). * Renal dysfunction, defined as estimated glomerular filtration rate \<60 mL/min/1.73 m². * Hepatic dysfunction, defined as liver enzyme levels greater than twice the upper limit of normal. * History of bleeding disorders or coagulopathy. * Active or recent peptic ulcer disease. * Current use of recreational drugs, including cannabis, that in the judgment of the investigators could interfere with anesthesia management, postoperative pain assessment, or study outcomes. * Any medical condition that, in the judgment of the investigators, would make participation unsafe or interfere with study participation.