What is the recommended intravenous (IV) adrenaline dosing for anaphylaxis in adults and children of different age groups?

IV Adrenaline Dosing for Anaphylaxis

For adults, administer IV adrenaline at an initial dose of 50 mcg (0.5 mL of 1:10,000 solution), repeated as needed for severe hypotension or bronchospasm; for children, use 1 mcg/kg as the starting dose, titrated carefully to response. 1

Critical Context: IV Route is NOT First-Line

Intramuscular (IM) administration in the anterolateral thigh is the preferred and safer route for anaphylaxis treatment in nearly all settings. 2, 3 IV adrenaline should be reserved exclusively for:

• Patients in cardiac arrest 1, 4
• Severe refractory hypotension despite multiple IM doses and aggressive fluid resuscitation 2, 4
• Settings with continuous hemodynamic monitoring (operating theatres, intensive care units) 1

The IV route carries significant risk of dilution/dosing errors and serious cardiac adverse effects including arrhythmias and myocardial ischemia. 2

Adult IV Dosing Protocol

Initial Bolus Dosing

• Start with 50 mcg (0.5 mL of 1:10,000 solution) administered slowly IV 1
• Repeat every few minutes as needed for persistent severe hypotension or bronchospasm 1
• For cardiac arrest: escalate rapidly to 1-3 mg (1:10,000) over 3 minutes, then 3-5 mg over 3 minutes 1, 4

IV Infusion for Refractory Cases

• Prepare by adding 1 mg (1 mL) of 1:1,000 adrenaline to 250 mL D5W to yield 4 mcg/mL concentration 2, 4
• Start infusion at 1-4 mcg/min, titrate up to maximum 10 mcg/min based on clinical response 1, 2, 4
• Requires continuous cardiac monitoring and blood pressure monitoring 1

Pediatric IV Dosing Protocol

Preparation and Initial Dosing

• Prepare a syringe containing 1 mL of 1:10,000 adrenaline for each 10 kg body weight 1
• This yields 0.1 mL/kg of 1:10,000 solution = 10 mcg/kg total available 1
• Start with 1 mcg/kg (one-tenth of the prepared syringe contents) and titrate to response 1
• Children often respond to doses as low as 1 mcg/kg 1
• In smaller children, further dilution may be necessary to allow precise dose titration 1

Pediatric Cardiac Arrest Dosing

• Initial resuscitation dose: 0.01 mg/kg (0.1 mL/kg of 1:10,000 solution, maximum 0.3 mg) 1
• Repeat every 3-5 minutes for ongoing arrest 1
• For unresponsive asystole or pulseless electrical activity, consider higher doses: 0.1-0.2 mg/kg (0.1 mL/kg of 1:1,000 solution) 1

Critical Safety Considerations

Concentration Confusion Prevention

• IM/SC route uses 1:1,000 (1 mg/mL) concentration 3, 5
• IV route uses 1:10,000 (0.1 mg/mL) concentration 1, 2
• Administering 1:1,000 concentration IV can cause fatal arrhythmias—this is a common and deadly error 2

Monitoring Requirements

• Continuous cardiac monitoring is mandatory during IV administration 1, 4
• Monitor for tachycardia, arrhythmias, hypertension, and myocardial ischemia 1
• Avoid repeated injections at the same site due to vasoconstriction-induced tissue necrosis 3

Concurrent Management Essentials

Fluid Resuscitation

• Administer 0.9% saline or lactated Ringer's solution at high rate via large-bore IV 1
• Adults: 1,000-2,000 mL bolus 2, 4
• Children: 20 mL/kg bolus 4

Adjunctive Medications (Secondary to Adrenaline)

• H1-antihistamine: Diphenhydramine 25-50 mg IV (1-2 mg/kg in children) 1, 4
• H2-antihistamine: Ranitidine 50 mg IV (1 mg/kg in children) 1, 4
• Corticosteroids: Hydrocortisone 200 mg IV for adults (age-adjusted for children: 100 mg for 6-12 years, 50 mg for 6 months-6 years, 25 mg for <6 months) 1

Special Population: Beta-Blocker Patients

• If refractory to adrenaline despite adequate dosing and fluids, administer glucagon 1-5 mg IV over 5 minutes (20-30 mcg/kg in children, maximum 1 mg), followed by infusion at 5-15 mcg/min 1, 4
• Glucagon bypasses beta-receptor blockade and can restore responsiveness to adrenaline 4

Common Pitfalls to Avoid

1. Using IV route as first-line treatment: IM administration achieves therapeutic levels faster and more safely in most cases 2, 3
2. Inadequate dose titration: Starting too high with IV boluses increases cardiac risk; starting too low may be ineffective 1, 2
3. Failing to prepare for repeat dosing: Adrenaline has a short half-life (minutes), and most patients require multiple doses 1, 2
4. Delaying fluid resuscitation: Massive fluid shifts occur in anaphylaxis; aggressive volume replacement is essential alongside adrenaline 1, 4
5. Premature discontinuation: Observe patients for minimum 6 hours after symptom resolution due to risk of biphasic reactions 1, 6