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Epinephrine

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Epinephrine

Key Points

  • Epinephrine (adrenaline) is a potent alpha- and beta-adrenergic receptor agonist (catecholamine).
  • First-line treatment for anaphylaxis and a key agent in cardiac resuscitation (ACLS).
  • Produces bronchodilation, increased heart rate and contractility, and peripheral vasoconstriction.
  • EpiPen (auto-injector) effects fade after 15 to 20 minutes; seek emergency medical care immediately after use.
  • Emergency use requires concentration-aware dosing: cardiac-arrest IV bolus pathways and anaphylaxis IM pathways use different concentrations.

Mechanism of Action

Epinephrine stimulates both alpha- and beta-adrenergic receptors. Alpha-1 stimulation causes peripheral vasoconstriction, raising blood pressure. Beta-1 stimulation increases heart rate and myocardial contractility. Beta-2 stimulation causes bronchodilation and relaxation of smooth muscle. These combined effects support circulation and airway patency in emergency situations. Depending on dose, beta-2 vasodilatory effects can predominate at lower exposure and alpha-1 vasoconstrictive effects can dominate at higher exposure.

Indications

  • Severe allergic reactions (anaphylaxis) — first-line treatment.
  • Acute bronchospasm during severe asthma attacks.
  • Cardiac resuscitation (ACLS protocol).
  • Severe hypotension in shock states.
  • Local injection to control superficial bleeding (vasoconstrictor effect).

Emergency Dosing Cues (Adult, Protocol-Dependent)

  • Cardiac arrest (VF/pulseless VT/asystole/PEA): 0.1-1 mg IV bolus using the 0.1 mg/mL concentration, commonly repeated about every 5 minutes during resuscitation.
  • Anaphylaxis: 0.3-0.5 mg IM using the 1 mg/mL concentration; repeat every 5-10 minutes as needed per severity and protocol.

Nursing Considerations

  • Monitor heart rate, blood pressure, and cardiac rhythm continuously during IV administration.
  • Monitor respiratory status closely during IV administration, including respiratory rate and work of breathing.
  • Assess for extravasation at IV site; epinephrine can cause tissue necrosis.
  • If extravasation causes local ischemic changes, anticipate phentolamine rescue per protocol.
  • Check EpiPen expiration date; store at room temperature and protect from light.
  • Effects of intramuscular injection (EpiPen) fade after 15 to 20 minutes; ensure emergency medical follow-up.
  • Use with caution in clients with cardiac arrhythmias, coronary artery disease, or hyperthyroidism.
  • Epinephrine contains sodium bisulfite; screen for sulfite hypersensitivity when history suggests risk.
  • Avoid end-arterial local-injection use in fingers, toes, ears, nose, or genitalia because severe vasoconstriction can cause ischemic injury.
  • Contraindicated in narrow-angle glaucoma.
  • Discard discolored IV epinephrine solutions.
  • If blood pressure rises sharply during IV use, follow protocol for rapid control (for example rapid-acting vasodilator pathways).
  • In life-threatening resuscitation/anaphylaxis pathways, expected benefit generally outweighs many routine contraindication concerns; continue protocol-led monitoring.

Side Effects and Adverse Effects

  • Common: Hypertension, tachycardia, palpitations, anxiety, tremor, headache.
  • Serious: Cardiac arrhythmias, myocardial ischemia, hypertensive crisis, pulmonary edema, cerebral hemorrhage.
  • Metabolic: Hypokalemia and lactic acidosis can occur in high-acuity dosing contexts.
  • Local: Tissue necrosis from extravasation or repeated local injection.

Health Teaching

  • Clients with anaphylaxis risk should carry an EpiPen at all times.
  • Administer EpiPen into the outer thigh; can inject through clothing in emergencies.
  • Seek immediate emergency medical care after EpiPen use because effects are temporary.
  • Replace EpiPen before expiration date; check clarity of solution regularly.
  • For food-allergy pathways, teach proactive ingredient-label review and allergy disclosure before meals prepared by others.
  • anaphylaxis - Primary emergency indication for epinephrine.
  • atropine - Co-administered in cardiac emergency contexts (ACLS).
  • beta-blockers - Pharmacologic antagonist relationship.

Self-Check

  1. Why is epinephrine the first-line drug for anaphylaxis?
  2. What monitoring is essential during IV epinephrine administration?
  3. Why must clients seek emergency care after using an EpiPen even if symptoms improve?

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