Under what circumstances is epinephrine (epi) given in cardiac arrest and why?

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Last updated: June 6, 2025View editorial policy

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From the Guidelines

Epinephrine should be administered to patients in cardiac arrest as a first-line medication for all shockable and non-shockable rhythms, with a standard dose of 1 mg intravenously or intraosseously every 3-5 minutes for the duration of the resuscitation effort. This recommendation is based on the most recent and highest quality study, which found that epinephrine significantly increases return of spontaneous circulation (ROSC) and survival to hospital discharge, although its effect on neurological outcome remains uncertain 1. The medication works through its alpha-adrenergic effects, which cause peripheral vasoconstriction, increasing coronary and cerebral perfusion pressures during chest compressions.

Key Points:

  • Epinephrine should be given as early as possible in non-shockable rhythms (asystole and pulseless electrical activity) 1.
  • In shockable rhythms (ventricular fibrillation and pulseless ventricular tachycardia), epinephrine is administered after initial defibrillation attempts have failed 1.
  • The standard dose of epinephrine is 1 mg intravenously or intraosseously every 3-5 minutes, with a higher dose of 2-2.5 mg via the endotracheal tube for patients without IV/IO access.
  • The use of high-dose epinephrine is not recommended, as it has not been shown to improve survival to discharge with favorable neurological outcome 1.

Rationale:

The use of epinephrine in cardiac arrest is supported by several studies, including a meta-analysis of two randomized controlled trials that found a significant increase in ROSC and survival to hospital discharge with epinephrine administration 1. While the effect of epinephrine on neurological outcome remains uncertain, the available evidence suggests that it may improve survival with favorable neurological outcome, particularly for patients with initial non-shockable rhythm 1.

Clinical Implications:

The administration of epinephrine during cardiac arrest should be guided by the most recent and highest quality evidence, with a focus on improving ROSC and survival to hospital discharge. Clinicians should be aware of the potential benefits and limitations of epinephrine therapy and use it in conjunction with other evidence-based treatments, such as high-quality CPR and defibrillation, to optimize patient outcomes.

From the Research

Circumstances for Epinephrine Administration in Cardiac Arrest

  • Epinephrine is administered in cardiac arrest when initial CPR and defibrillation are unsuccessful in patients with shockable rhythms, with a recommended dose of 1 mg 2.
  • In patients with non-shockable rhythms, epinephrine 1 mg is recommended to be administered as soon as feasible 2.
  • The American Heart Association states that epinephrine is reasonable for patients with cardiac arrest, although the literature behind its use is not strong 3.

Rationale for Epinephrine Use

  • Epinephrine may improve rates of return of spontaneous circulation (ROSC), but it is not associated with improved survival with a favorable neurologic outcome 2, 3.
  • The combination of vasopressin, steroids, and epinephrine may improve ROSC among those with in-hospital cardiac arrest, but there is no improvement in survival to discharge and survival with a favorable neurologic outcome 2.
  • Timing of epinephrine administration may affect patient outcome, with earlier administration potentially leading to improved outcomes 3, 4.

Dosage and Administration

  • The optimal dose of epinephrine is not known, but reducing the dose of epinephrine administered during out-of-hospital cardiac arrest was not associated with a change in survival to hospital discharge or favorable neurological outcomes 5.
  • Dosing of epinephrine has been standardized at 1 mg per administration in adults, with higher doses potentially being harmful 4.
  • Intravenous is the preferred route of administration for epinephrine, but new research suggests intramuscular administration may be beneficial 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Emergency medicine updates: Cardiac arrest medications.

The American journal of emergency medicine, 2025

Research

Emergency Medicine Myths: Epinephrine in Cardiac Arrest.

The Journal of emergency medicine, 2017

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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