Anaphylaxis

Initial management — allergic reaction
  • Remove trigger (stop infusion, remove stinger) and call for help.
  • Assess ABCs — airway patency, work of breathing, perfusion, mental status.
  • Position: supine with legs elevated; semi-recumbent if dyspneic; recovery position if vomiting. Avoid sudden upright posture.
  • Give IM epinephrine immediately if any airway, breathing, circulation, or 2-system involvement — do not wait for IV or antihistamines.
  • High-flow O₂ via NRB; prepare airway equipment for early intubation if stridor/angioedema.
  • IV access ×2 large-bore; start NS/LR bolus (adult 1–2 L, peds 20 mL/kg) for hypotension.
  • Continuous monitoring: SpO₂, ECG, NIBP q5 min.
  • Adjuncts after epi (do not delay epi):
    • () 25–50 mg IV/IM (peds 1 mg/kg, max 50 mg) — H1 blocker.
    • () 20 mg IV (peds 0.25 mg/kg, max 20 mg) — H2 blocker.
    • () 125 mg IV (peds 1–2 mg/kg, max 125 mg) — corticosteroid.
    • 2.5–5 mg nebulized (peds 2.5 mg) — for bronchospasm/wheezing; repeat PRN.
  • Reassess q5 min — repeat IM epi q5–15 min PRN; escalate to epi infusion if refractory.
Initial epinephrine dose · IM
  • Adult: 0.3–0.5 mg IM (0.3–0.5 mL of 1 mg/mL / 1:1,000).
  • Pediatric: 0.01 mg/kg IM, max 0.3 mg/dose (0.01 mL/kg of 1 mg/mL).
  • Auto-injector: 0.3 mg (≥ 30 kg) · 0.15 mg (10–30 kg).
  • Site: mid-anterolateral thigh (vastus lateralis), 90° to skin.
  • Concentration: use 1 mg/mL (1:1,000) for IM — never 0.1 mg/mL (1:10,000).
  • Repeat q5–15 min PRN; alternate thighs. Most patients need ≥ 2 doses.
Patient
Weight
Epinephrine supply
IM

All volume calculations on this page use 1 mg/mL (1:1,000).

IM Epi · live dose
0.01 mg/kg

Enter weight to see live dose. Adult max 0.5 mg · Peds max 0.3 mg.

Management
IM Epinephrine (first-line)
  • : 0.01 mg/kg IM (max 0.5 mg adult, 0.3 mg peds)
  • (1 mg/mL (1:1,000)): —
  • : Every 5–15 min PRN. Most patients need ≥ 2 doses.
Fluid resuscitation
  • : Adult 1–2 L · Peds 20 mL/kg
  • : Up to 30 mL/kg (peds) or 2–4 L (adult) for hypotension
Adjuncts (after epi — do not delay epi)

Do NOT delay epinephrine
Antihistamines and steroids are adjuncts only — they do not treat upper airway obstruction or shock. IM epi is first-line. If epi hasn't been given, give it now before any of these drugs.

  • : 1 mg/kg IV (max 50 mg)
  • : 0.25 mg/kg IV (max 20 mg)
  • : 1–2 mg/kg IV (max 125 mg)
  • : 2.5–5 mg neb for bronchospasm
Refractory (after 2+ IM doses)
  • : 0.05–0.5 mcg/kg/min IV, titrate
  • : 4 mg / 250 mL D5W = 16 mcg/mL
  • : —
  • : 1–5 mg IV over 5 min (if on β-blocker)
  • : 1–2 mg/kg IV for refractory vasoplegia
  • : Early intubation if stridor / angioedema progressing
Epi-induced arrhythmia / cardiotoxicity

Suspect when tachydysrhythmia, chest pain, severe HTN, or ischemic ECG changes appear after IM/IV epi — especially in elderly, CAD, or after an inadvertent IV push or concentrated dose.

  • (stable): Vagal → adenosine 6 mg IV, then 12 mg. Avoid additional epi
  • (stable): Amiodarone 150 mg IV over 10 min; correct K⁺/Mg²⁺
  • : Synchronized cardioversion or defibrillation per ACLS
  • : Nitroglycerin SL/IV or phentolamine 1–5 mg IV (α-blocker)
  • : Atropine 0.5–1 mg IV; pacing if unstable
Disposition checklist
0 / 10 complete

Checklist saves locally in this browser. Reset between patients.

Educational reference only. Always follow current guidelines and institutional protocols.