Trial Evaluating the Analgesic Efficacy of Magnesium Sulfate as an Adjuvant to Bupivacaine in Local Wound Infiltration for Patients Undergoing Modified Radical Mastectomy (MRM) With Axillary Clearance

This is a double-blind, randomized, controlled clinical trial evaluating the analgesic efficacy and safety of magnesium sulfate as an adjuvant to bupivacaine for local wound infiltration in patients undergoing modified radical mastectomy with axillary clearance. Participants will be randomized to receive either magnesium sulfate 750 mg with bupivacaine or the control intervention. Postoperative pain, analgesic requirements, and safety outcomes will be assessed during the postoperative period, including a follow-up safety assessment between Day 7 and Day 14 after surgery.

Inclusion Criteria: * Adult female patients (age ≥18 years) undergoing elective modified radical mastectomy (MRM) with axillary clearance. * ASA physical status I-III. * Willingness to participate and provide informed consent. Exclusion Criteria: * Allergy to bupivacaine or magnesium. * Chronic opioid use or pre-existing chronic pain conditions. * Significant renal or hepatic impairment. * Pregnancy or lactation. * Neuromuscular disorders. * Abnormal baseline serum magnesium levels (e.g., hypermagnesemia).