Norepinephrine vs. Phenylephrine for Hypotension in Low-Dose Spinal Anesthesia for Cesarean Delivery

NCT07327320 | Completed Phase 4

• 1 other identifier: TA2.24.03
• Study Type: interventional
• Target: 100
• Locations: 1 country
• Sites: 1

Brief Summary

This clinical trial was conducted to compare the effectiveness and safety of two medications, norepinephrine and phenylephrine, in preventing hypotension during low-dose spinal anesthesia for cesarean delivery (CD). Although low-dose spinal anesthesia combined with opioids is widely used to mitigate hypotension, the incidence remains unacceptably high. Thus, vasopressors remain essential in maintaining maternal blood pressure during these procedures. In this study, 100 women were initially assessed, with 2 excluded. The remaining 98 were randomly assigned to receive a continuous infusion of either norepinephrine or phenylephrine. During the follow-up process, 2 patients from each group were lost, resulting in 47 participants per group for final analysis. The results showed that norepinephrine was significantly more effective, with a lower incidence of hypotension (14.9% vs. 42.6%). It also provided more stable heart rates with fewer episodes of bradycardia and less need for rescue medications. Both treatments were safe for the babies with comparable Apgar scores. This study suggests that Norepinephrine infusion at 0.05 mcg/kg/min is more effective than phenylephrine at 0.25 mcg/kg/min in preventing hypotension during low-dose SA in CD, providing better hemodynamic stability and fewer episodes of bradycardia

Conditions

Spinal; Cesarean Section; Hypotension, Controlled; Anesthesia

Keywords

Norepinephrine; Phenylephrine; Hypotension; Spinal anaesthesia; Cesarean delivery

Outcome Measures

Primary Outcomes (1)

• Hypotension

  Hypotension was defined as systolic blood pressure (SBP) \< 90 mmHg or a drop of more than 20% from baseline.

  From the completion of spinal injection until 5 minutes after the neonate is delivered.

Secondary Outcomes (6)

• Bradycardia

  From the completion of spinal injection until 5 minutes after the neonate is delivered.

• Hypertension

  From the completion of spinal injection until 5 minutes after the neonate is delivered

• Severe hypotension

  From the completion of spinal injection until 5 minutes after the neonate is delivered

• Requirement for rescue vasopressors (phenylephrine or ephedrine) and atropine

  From the completion of spinal injection until 5 minutes after the neonate is delivered

• Nausea and vomiting

  From the completion of spinal injection until 5 minutes after the neonate is delivered

Study Arms (2)

Norepinephrine

EXPERIMENTAL

Continuous intravenous norepinephrine infusion was administered at 0.05 mcg/kg/min, prepared by diluting 100 mcg in 50 mL of 0.9% sodium chloride

Drug: Norepinephrine

Phenylephrine

EXPERIMENTAL

Continuous intravenous phenylephrine infusion was administered at 0.25 mcg/kg/min, prepared by diluting 500 mcg in 50 mL of 0.9% sodium chloride

Drug: Phenylephrine

Interventions

Norepinephrine DRUG

Continuous intravenous norepinephrine infusion was administered at 0.05 mcg/kg/min, prepared by diluting 100 mcg in 50 mL of 0.9% sodium chloride

Norepinephrine

Phenylephrine DRUG

Continuous intravenous phenylephrine infusion was administered at 0.25 mcg/kg/min, prepared by diluting 500 mcg in 50 mL of 0.9% sodium chloride

Phenylephrine

Eligibility Criteria

• Age: 18 Years+
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Parturients aged ≥18 years
• Classified as American Society of Anesthesiologists physical status II
• Term singleton pregnancies
• Scheduled for elective CD under SA

You may not qualify if:

• Refusal to participate.
• Fetal anomalies or suspected fetal compromise
• Preeclampsia or eclampsia
• Conversion to general anesthesia or use of labor analgesia
• Contraindication to SA
• Preexisting cardiovascular or cerebrovascular disease; chronic hypertension
• Baseline bradycardia
• Current use of cardiovascular or antihypertensive medications
• Body mass index more than 40 kg/m²
• Body weight less than 50 kg or more than 100 kg

Sponsors & Collaborators

• Tam Anh Research Institute: lead

Study Sites (1)

Tam Anh TP. Ho Chi Minh General Hospital

Ho Chi Minh City, Ho Chi Minh, 700000, Vietnam

Location

Related Publications (1)

• 1. Afolabi BB, Lesi FEA. Regional versus general anaesthesia for caesarean section. Cochrane Database of Systematic Reviews. 2012(10). doi: 10.1002/14651858.CD004350.pub3. PubMed PMID: CD004350. 2. Vallejo MC, Attaallah AF, Elzamzamy OM, Cifarelli DT, Phelps AL, Hobbs GR, et al. An open-label randomized controlled clinical trial for comparison of continuous phenylephrine versus norepinephrine infusion in prevention of spinal hypotension during cesarean delivery. International journal of obstetric anesthesia. 2017;29:18-25. Epub 2016/10/11. doi: 10.1016/j.ijoa.2016.08.005. PubMed PMID: 27720613. 3. Klöhr S, Roth R, Hofmann T, Rossaint R, Heesen M. Definitions of hypotension after spinal anaesthesia for caesarean section: literature search and application to parturients. Acta anaesthesiologica Scandinavica. 2010;54(8):909-21. Epub 2010/05/12. doi: 10.1111/j.1399-6576.2010.02239.x. PubMed PMID: 20455872. 4. Herbosa GAB, Tho NN, Gapay AA, Lorsomradee S, Thang CQ. Consensus on the Southeast Asian management of hypotension using vasopressors and adjunct modalities during cesarean section under spinal anesthesia. Journal of Anesthesia, Analgesia and Critical Care. 2022;2(1):56. doi: 10.1186/s44158-022-00084-1. 5. Kinsella SM, Carvalho B, Dyer RA, Fernando R, McDonnell N, Mercier FJ, et al. International consensus statement on the management of hypotension with vasopressors during caesarean section under spinal anaesthesia. Anaesthesia. 2018;73(1):71-92. Epub 2017/11/02. doi: 10.1111/anae.14080. PubMed PMID: 29090733. 6. Allen TK, George RB, White WD, Muir HA, Habib AS. A double-blind, placebo-controlled trial of four fixed rate infusion regimens of phenylephrine for hemodynamic support during spinal anesthesia for cesarean delivery. Anesthesia and analgesia. 2010;111(5):1221-9. Epub 2010/05/25. doi: 10.1213/ANE.0b013e3181e1db21. PubMed PMID: 20495139. 7. Habib AS. A Review of the Impact of Phenylephrine Administration on Maternal Hemodynamics and Maternal and Neonatal Outc

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Related Links

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MeSH Terms

Conditions

Hypotension

Interventions

Norepinephrine; Phenylephrine

Condition Hierarchy (Ancestors)

Vascular Diseases; Cardiovascular Diseases

Intervention Hierarchy (Ancestors)

Ethanolamines; Amino Alcohols; Alcohols; Organic Chemicals; Amines; Biogenic Monoamines; Biogenic Amines; Catecholamines; Catechols; Phenols; Benzene Derivatives; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic; Hydrocarbons

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Masking Details: The randomization sequence was concealed in sequentially numbered, opaque, sealed envelopes. Each envelope contained the specific intervention protocol for the assigned group. The Principal Investigator generated the allocation sequence and prepared the envelopes prior to the study. To ensure concealment, the recruiting investigator opened the next envelope in the sequence only after the participant was enrolled, thereby determining the group assignment. This was a single-blind study; only the participants were blinded to the group allocation. Due to the nature of vasopressor administration and the need for real-time hemodynamic management, the investigators and the anesthesiology team were aware of the assigned intervention to ensure patient safety and proper medication delivery
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: This was a randomized, controlled, single-blind trial with a parallel group design and a 1:1 allocation ratio.

Study Record Dates

• First Submitted: December 24, 2025
• First Posted: January 8, 2026
• Study Start: June 6, 2024
• Primary Completion: October 4, 2025
• Study Completion: October 4, 2025
• Last Updated: January 21, 2026

Record last verified: 2025-12

Locations

VN (1)