Background and aims Spinal anaesthesia is commonly used for elective caesarean section. The aim of this study was to evaluate the efficacy of intrathecal or intravenous dexamethasone to prevent some early complications of spinal anaesthesia such as arterial hypotonia, nausea, vomiting, bradycardia, shivering etc.

Methods We conducted a randomized, prospective, double-blinded, placebo-controlled clinical trial. A total of 124 healthy, non-obese women, ASA I-II, 18–36 years old undergoing elective cesarean section under spinal anaesthesia were divided into three equal groups. The women of each group received intrathecal hyperbaric bupivacaine 0.5% 10 mg. Group B (n=41) additionally received intrathecal 1 ml of normal saline=placebo; Group BD (n=42) additionally received 4 mg (1 ml) intrathecal dexamethasone, and Group D (n=41) received 8 mg intravenous dexamethasone directly after spinal puncture. The patients were evaluated for blood pressure, heart rate, nausea, vomiting, shivering or other complications during intra- or postoperative period (24h).

Results The addition of intrathecal dexamethasone in Group BD vs Group B significantly decreased frequency and manifestations of arterial hypotonia and nausea (Pearson’s χ2 =0.486 and χ2=0.479, p<0.05); reduced shivering (Pearson’s χ2=0.316, p<0.05), and significantly did not affect on vomiting and bradycardia. There were no significant differences between intravenous dexamethasone in Group D and placebo in Group B (p>0.05).

Conclusions The addition of 4 mg intrathecal dexamethasone as an adjuvant for spinal anaesthesia in elective cesarean section can significantly decrease frequency and manifestations of arterial hypotonia and nausea, reduce shivering during perioperative period. The addition of 8 mg intravenous dexamethasone does not have the same quality.