The aim of this study is to compare the efficacy of magnesium sulphate, ondansetron, and dexmedetomidine in managing post-spinal anesthesia shivering. The primary aim is the time to cessation of shivering after drug administration, while secondary aim include hemodynamic parameters (heart rate, blood pressure, SpO₂ ) and the recurrence of shivering

This is a randomized double blinded study including patients undergoing surgery under spinal anesthesia. Patients will be randomly allocated into three groups to receive magnesium sulphate, ondansetron, or dexmedetomidine for the treatment of post-spinal anesthesia shivering. The time to cessation of shivering, hemodynamic parameters, and recurrence of shivering will be recorded.

Inclusion Criteria:

• Age from 18 to 45 years.
• Both sexes.
• American Society of Anesthesiologists physical status I, II
• Scheduled for elective lower abdominal or lower limb surgeries under spinal anesthesia

Exclusion Criteria:

• Patients with known allergy to study drugs.
• Patients with baseline body temperature outside the normal range (36-37.5°C).
• History of thermoregulatory disorders, thyroid dysfunction, or neurological diseases.
• Patients receive sedatives, antipsychotics, or antidepressants.
• Patients require intraoperative conversion to general anesthesia.

A decision regarding sharing individual participant data has not yet been made. This will depend on future agreements, ethical approvals, and data governance policies.