Key result
Norepinephrine matches phenylephrine in preventing post-spinal hypotension but reduces bradycardia to 0%.
Why the study?
Norepinephrine is emerging as an alternative to phenylephrine to prevent post-spinal hypotension during cesarean delivery due to less reflex bradycardia, prompting a comparison of their efficacy and safety.
Does prophylactic intravenous norepinephrine prevent post-spinal hypotension as effectively as phenylephrine in parturients undergoing cesarean section?
RCT (n=102)
Double-blind
Computer-generated random numbers
No
Does prophylactic intravenous norepinephrine prevent post-spinal hypotension as effectively as phenylephrine in parturients undergoing cesarean section?
Absolute Event Rate: 27.08% vs 21.28%
p-value: p=0.509
Prophylactic intravenous norepinephrine is as effective as phenylephrine in preventing post-spinal hypotension during cesarean section but with a significantly lower risk of maternal bradycardia.
Norepinephrine matches phenylephrine for post-spinal hypotension prevention in cesarean delivery while eliminating bradycardia; extends vasopressor options and supports confirmatory trials.
Background Prophylactic vasopressor infusion is commonly recommended during cesarean section under spinal anesthesia to prevent hypotension. Norepinephrine is gaining recognition as a viable alternative to phenylephrine in obstetric anesthesia, primarily due to its lower propensity to cause reflex bradycardia. This study compares the efficacy and safety of prophylactic intravenous infusions of norepinephrine and phenylephrine, administered at varying infusion rates, on maternal hemodynamics and neonatal outcomes during cesarean delivery. Methods In this prospective, randomized, double-blinded study, 102 parturients of ASA physical status 2, undergoing cesarean section under Lucas Grade 1 and 2, were randomized into two groups to receive prophylactic manually adjusted intravenous infusions of norepinephrine or phenylephrine. The primary objective was to compare the efficacy of norepinephrine and phenylephrine in preventing post-spinal hypotension. The safety of these two drugs with respect to the neonatal outcome and maternal bradycardia, nausea, and vomiting was the secondary objective. Results Ninety-five parturients were analyzed, and the incidence of hypotension was similar between the two groups (27.08% vs. 21.28%, p = 0.509). However, the phenylephrine (PE) group had a significantly higher incidence of bradycardia compared to the norepinephrine (NE) group (19.15% vs. 0%, p = 0.001). The incidence of nausea and vomiting was comparable in groups NE and PE ( 4.17% vs. 10.64%, p = 0.268). The number of manual physician interventions was similar between the groups (27.08% vs 21.28%, p = 0.509). Neonatal cord blood ABG parameters were comparable between the groups. Conclusion Prophylactic intravenous infusions of phenylephrine and norepinephrine showed similar efficacy in preventing hypotension. However, the use of norepinephrine did not cause bradycardia as compared to phenylephrine.
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Mujahid et al. (2025) conducted an RCT in Hypotension after subarachnoid block in caesarean section (n=102). Norepinephrine vs. Phenylephrine (starting at 25 mcg/min, 50 mcg/ml concentration) was evaluated on Incidence of post-spinal hypotension (p=0.509). Norepinephrine and phenylephrine showed similar efficacy in preventing post-spinal hypotension (27.1% vs 21.3%, p=0.509), but norepinephrine eliminated bradycardia (0% vs 19.2%, p=0.001).
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