Comparative study between dexamethasone and ondansetron for prevention of shivering during spinal anaesthesia Adel Rizk Botros, Wafaa Ibrahim Abd el wahid Khalil, Yasser Mohamed Nasr Background Shivering is one of frequent, undesirable adverse effects of spinal anaesthesia. The aim of this study was to compare the efficacy and safety of prophylactic intravenous administration of either 0.1mg/kg of dexamethasone or 4mg of ondansetron immediately before establishment of spinal block for prevention of shivering during spinal anaesthesia. Patients and methods:A total of 90 patients of both gender of ASA physical status class I and II between 21 and 60 years old scheduled for elective lower body surgeries under spinal anaesthesia were randomly allocated into three groups: Control group (C group) received 10 ml normal saline; Dexamethasone group (D Group) received 0.1mg/kg dexamethasone and ondansetron group (O Group) received 4 mg ondansetron. Studied drugs were given intravenously (IV) immediately before establishment of spinal block. Results: Dexamethasone and ondansetron significantly reduced incidence and severity of shivering during spinal anaesthesia with no statistically significant difference between both of them. No significant associated side effects occurred with dexamethasone nor ondansetron when used for prevention of shivering during spinal anaesthesia. Conclusion: Both dexamethasone and ondansetron are efficient and safe in reducing the incidence and severity of shivering during spinal anaesthesia and no one is superior to the other