A randomised double-blind comparison of phenylephrine and norepinephrine for the management of postspinal hypotension in pre-eclamptic patients undergoing caesarean section
Related Experiment Video
Updated: Oct 20, 2025
In Vivo Real-Time Study of Drug Effects on Carotid Blood Flow in the Ovine Fetus
Published on: April 28, 2023
Medha Mohta1, Lakshmi R, Geetanjali T Chilkoti
1From the Department of Anaesthesiology and Critical Care, University College of Medical Sciences and Guru Teg Bahadur Hospital (MM, LR, GTC), Department of Obstetrics and Gynaecology, University College of Medical Sciences and Guru Teg Bahadur Hospital (RA), Delhi Cancer Registry, Dr BRA IRCH, All India Institute of Medical Sciences, Delhi, India (RKM).
Background:
Studies comparing phenylephrine and norepinephrine for the treatment of postspinal hypotension in pre-eclamptic patients are limited.
Objective:
To compare bolus doses of phenylephrine and norepinephrine for treating hypotension in pre-eclamptic mothers undergoing caesarean section under spinal anaesthesia. It was hypothesised that norepinephrine and phenylephrine use would be associated with similar neonatal outcome.
Design:
Randomised controlled study.
Setting:
Single centre, tertiary care, university teaching hospital, from December 2018 to March 2020.
Patients:
A total of 86 women with pre-eclampsia and a singleton pregnancy who developed postspinal hypotension during caesarean section.
Interventions:
Patients received intravenous phenylephrine (50 μg) or norepinephrine (4 μg) for treatment of hypotension, defined as a fall in baseline systolic BP by ≥ 20% or an absolute value < 100 mmHg.
Main Outcome Measures:
The primary outcome was umbilical artery pH. Secondary outcomes included Apgar scores, the number of hypotensive episodes, vasopressor requirements, the incidence of tachycardia/bradycardia/arrhythmias/hypertension and maternal complications.
Results:
Umbilical artery pH was not different between the phenylephrine and norepinephrine groups (7.26 ± 0.06 and 7.27 ± 0.06, respectively; P = 0.903). The median [IQR] number of hypotensive episodes was higher in the norepinephrine than the phenylephrine group: 2 [1 to 3] vs 1 [1 to 2], respectively; P = 0.014. Apgar scores, total number of vasopressor boluses required, systolic BP trends and the incidence of maternal complications were comparable in the two groups. Heart rate (HR) values were lower in phenylephrine group (P = 0.026), and one patient in phenylephrine group and none in the norepinephrine group developed bradycardia (HR < 50 bpm), P = 1.000.
Conclusions:
In women with pre-eclampsia undergoing caesarean section, bolus doses of phenylephrine (50 μg) and norepinephrine (4 μg) used to treat hypotension after spinal anaesthesia are equally effective with similar neonatal and maternal outcomes.
Trial Registration:
CTRI/2018/11/016478.
More Related Videos
Related Concept Videos
01:29Local Anesthetics: Clinical Application as Epidural Anesthesia
Since epidural anesthetics can be infused through an epidural catheter, all types of drugs, including short-acting ones, can be administered. Chloroprocaine and lidocaine are examples of short and long-duration anesthetics, respectively. Bupivacaine...
01:30Adrenergic Agonists: Therapeutic Uses
Emergency and Intensive Care Unit (ICU) applications: Pressor agents increase blood pressure, heart rate, and contractility in shock and organ failure situations. Dopamine can induce vasodilation and stimulate adrenoceptors. Endogenous catecholamines are effective in treating cardiogenic shock. α2-agonists like clonidine can reverse anesthesia-induced hypertension.
Allergies and...
01:25Cardiopulmonary Resuscitation IV: Pharmacological Management
01:18Adrenergic Agonists: Therapeutic Classification
Vasopressor or pressor agents: They increase blood pressure and function as cardiac stimulants. Examples include endogenous catecholamines (norepinephrine and dopamine) and synthetic agents (phenylephrine).
Bronchodilators: β2-agonists can relax bronchial muscles and widen airways. They are commonly used for treating obstructive pulmonary...
01:31Adrenergic Antagonists: ɑ and β-Receptor Blockers
01:28Adrenergic Agonists: Mixed-Action Agents
Ephedrine and pseudoephedrine lack a catecholamine group, making them less susceptible to degradation by metabolic enzymes. They have increased oral bioavailability and lipophilicity, resulting in a longer duration of action. Their response is reduced by...