Intravenous clonidine versus granisetron for prevention of postspinal anesthesia shivering in cesarean section

Background Shivering is a common and annoying side effect of spinal anesthesia. Recently, antishivering drugs, including clonidine and granisetron have been introduced as potential treatments. Aim To compare the effectiveness of intravenous clonidine and granisetron in preventing shivering that occurs after spinal anesthesia for cesarean section (CS). Patients and method One hundred eighty-six parturients scheduled for CS were allocated randomly into three groups, 62 patients each to receive intravenous clonidine 0.5 μg/kg (group Cl), 1 mg granisetron (group G) or 10 ml normal saline (group C), 20 min before spinal anesthesia. CS was started when the sensory level reached T6 and the bromage scale was 3. The primary outcome was the incidence of shivering, while secondary outcomes included maternal core body temperature, vital signs and satisfaction, neonatal outcomes, and maternal and neonatal adverse effects. Results The incidence of clinically significant shivering more than or equal to 3 was 11.3, 16.1, and 50% in groups CL, G, and C, respectively. The shivering intensity was the lowest in the clonidine and granisetron groups. The tympanic temperature did not show a significant difference among groups. A lower intraoperative mean arterial pressure and heart rate were reported in the CL group, but there was no significant difference in the incidence of hypotension and bradycardia between groups. A significantly lower incidence of nausea and vomiting and a higher incidence of satisfaction score 5 were recorded in group G. Other adverse effects and neonatal outcomes were comparable between groups. Conclusion Both clonidine and granisetron demonstrated comparable antishivering effects, which were significantly superior to placebo. Granisetron was also associated with a significant reduction in the incidence of nausea and vomiting, as well as an increase in patient satisfaction.