Introduction

  • The hemodynamic effects of epinephrine have long been studied, with growing concern about deleterious effects on cerebral and myocardial oxygen supply/demand balance.
  • More recently, norepinephrine has been considered for post–cardiac arrest (post-ROSC) shock to minimize the complications associated with epinephrine.

Clinical Detail

Pharmacology of epinephrine vs norepinephrine

CategoryEpinephrineNorepinephrine
Dose (infusion)Weight-based: 0.01–1 mcg/kg/min
Non-weight-based: 1–80 mcg/min
Institutional rates may vary		Weight-based: 0.05–1 mcg/kg/min (start 0.05–0.15)
Non-weight-based: 5–80 mcg/min (start 5–15)
Institutional rates may vary
PharmacokineticsOnset: immediate; rapid hepatic degradation; renal elimination; half-life <5 minOnset: immediate; rapid hepatic degradation; renal elimination; half-life <5 min
Mechanism
  • α-agonist → peripheral vasoconstriction → increased coronary and cerebral perfusion pressure
  • β-agonist (greater with epinephrine) → increased heart rate and contractility → increased myocardial oxygen demand and arrhythmia risk
Adverse effectsTachyarrhythmias, myocardial ischemia, extravasation/tissue necrosis.

Evidence

The comparative evidence is predominantly observational. Several cohorts and a 2025 meta-analysis associate epinephrine with worse outcomes (or favor norepinephrine), but the only randomized trial identified found no difference, and overall certainty is very low.

StudyDesign (n)ComparisonOutcome
Bougouin 2022
PMID 35129643		Observational multicenter cohort, propensity-adjusted (n=766 OHCA post-resuscitation shock)Epinephrine vs norepinephrineEpinephrine associated with higher all-cause hospital mortality (OR 2.6, 95% CI 1.4–4.7; P=0.002) and worse neurologic outcome.
Weiss 2021
PMID 34172611		Retrospective cohort (n=93)Initial norepinephrine vs epinephrine after ROSCEpinephrine more often had refractory hypotension, rearrest, or death in the ED (50% vs 22.2%; adjusted OR 3.94). Authors note this is hypothesis-generating (the epinephrine group had more pre-vasopressor rearrest — confounding).
Williams 2025
PMID 40440817		Systematic review & meta-analysis (6 studies, n=3458)Norepinephrine vs epinephrineNorepinephrine associated with 63% lower odds of recurrent arrest (OR 0.47, 95% CI 0.24–0.92), but no significant difference in hospital survival (OR 2.04, 95% CI 0.93–4.47) or unfavorable neurologic outcome; high heterogeneity (I²=89%).
Niemela 2025
PMID 41237843		Systematic review (1 RCT + 7 non-randomized; GRADE)Vasopressor choice in post-arrest hypotensionThe single RCT found no difference between noradrenaline and adrenaline; evidence certainty very low. The review does not support any specific vasopressor — randomized trials are needed.
Kim 2012
(SCCM 2012 abstract)		Retrospective conference abstract (n=90)Norepinephrine vs epinephrineSurvivors more likely to have received norepinephrine (34.8% vs 22.6%). Conference abstract only (not peer-review indexed) — low evidentiary weight.

A single case report (Mion 2014, PMID 24997106) describes transition from epinephrine to norepinephrine after recurrent VF with subsequent ROSC and recovery — case-level evidence only.

Conclusions

  • Norepinephrine is a reasonable vasopressor option for shock after return of spontaneous circulation (ROSC) and is favored in observational data — cohorts and a 2025 meta-analysis associate it with lower odds of recurrent arrest plus a cohort mortality signal versus epinephrine.
  • This signal rests on low-certainty, mostly observational evidence: the only randomized trial identified found no difference between norepinephrine and epinephrine, and a 2025 GRADE review rated overall certainty as very low. Norepinephrine should not be described as proven superior.
  • The optimal post-arrest vasopressor remains unsettled. The choice should be individualized — norepinephrine is a particularly reasonable option when epinephrine-related tachyarrhythmia or rearrest is a concern — and adequately powered randomized trials are still needed.

References

  • Norepinephrine; Epinephrine. Micromedex [Electronic version]. Greenwood Village, CO: Truven Health Analytics.
  • Callaway CW. Epinephrine for cardiac arrest. Curr Opin Cardiol. 2013;28(1):36-42. PMID: 23196774.
  • Epinephrine [package insert]. Lake Forest, IL: Hospira, Inc.; 2019.
  • Kim et al. The benefit of norepinephrine infusion for hemodynamic support following cardiopulmonary arrest and resuscitation. Crit Care Med. 2012;40(12 Suppl) (SCCM 2012 conference abstract).
  • Mion G, et al. Cardiac arrest: should we consider norepinephrine instead of epinephrine? Am J Emerg Med. 2014;32(12):1560.e1-2. PMID: 24997106.
  • Weiss A, et al. Comparison of clinical outcomes with initial norepinephrine or epinephrine for hemodynamic support after return of spontaneous circulation. Shock. 2021;56(6):988-993. PMID: 34172611.
  • Bougouin W, et al. Epinephrine versus norepinephrine in cardiac arrest patients with post-resuscitation shock. Intensive Care Med. 2022;48(3):300-310. PMID: 35129643.
  • Williams CA, et al. Norepinephrine versus epinephrine after cardiac arrest: a systematic review and meta-analysis. Am J Emerg Med. 2025;95:107-114. doi:10.1016/j.ajem.2025.05.038. PMID: 40440817.
  • Niemela VH, et al. The impact of vasopressor choice in patients with hypotension after cardiac arrest: a systematic review. Resuscitation. 2025;217:110892. doi:10.1016/j.resuscitation.2025.110892. PMID: 41237843.
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