High Dose but not Low Dose Granisetron Decreases Incidence and Severity of Post Anesthesia Shivering (PAS) and Postoperative Nausea and Vomiting (PONV) following Lower Abdominal Surgeries under Spinal Anesthesia

Background: Post Anesthesia Shivering (PAS) is one of the common complications throughout recovery from general and regional anesthesia. The incidence of this complication is reported to be 40-70% among patients. PAS occurrence depends on various factors such as age, gender and drugs used in anesthesia and surgery time. Granisetron is a serotonin 5HT3 receptor antagonist. Beneficial effects of such drugs have been shown in a limited number of studies. In this study, preventive effects of granisetron in prevention of shivering, nausea and vomiting following spinal anesthesia were evaluated in patients undergoing lower abdominal surgery. Methods: One hundred and five patients aged 1860 years and with ASA class I or II who were scheduled to undergo elective lower abdominal surgery under spinal anesthesia were studied in 3 groups of 35 patients. After spinal anesthesia, group L received low dose granisetron with a dose of 10μg/kg, group H received high dose granisetron with a dose of 40 μg/kg and group C received normal saline as placebo. After leaving the operating room, patients were monitored in terms of shivering occurrence, time and severity of it and incidence of nausea and vomiting. Results: Incidence of shivering, nausea and vomiting was significantly lower in group H than C. (P=0.009 and 0.008, respectively). However, there was no significant difference between L and C or L and H groups in terms of shivering, or nausea and vomiting occurrence. No side effects of granisetron were observed in the study. Conclusion: High dose granisetron with dose of 40μg/kg significantly reduced the prevalence and severity of PAS and PONV in comparison to placebo.