Prevention of Shivering Associated With Spinal Anesthesia

Patients will receive dexmedetomidine 0.5 mcg/kg diluted in 10 mL of NS given as IV infusion over 10 min before induction of spinal anesthesia

Patient will will receive ketamine 0.5 mg/kg diluted in 10 mL of NS given as IV infusion over 10 min before induction of spinal anesthesia

If the tested drug hasn't stopped shivering patient will receive 0.25 mg/kg meperidine