What is the recommended epinephrine infusion dosing, titration, and monitoring for adults (and children) with refractory anaphylaxis or vasodilatory shock?

Epinephrine Infusion Dosing and Management

For refractory anaphylaxis or vasodilatory shock in adults, initiate an epinephrine infusion at 0.05-2 mcg/kg/min (starting at the lower end and titrating upward every 10-15 minutes to achieve target mean arterial pressure), only after the patient has failed to respond to IV volume replacement and 2-3 intramuscular epinephrine doses of 0.3-0.5 mg. 1, 2

Preparation and Initial Dosing

Adults

Standard preparation options:

• Preferred method with infusion pump: Mix 1 mg epinephrine (1 mL of 1:1000) in 100 mL normal saline to create a 1:100,000 solution (10 mcg/mL). Start at 30-100 mL/h (5-15 mcg/min), titrating based on clinical response 1

• Alternative method: Mix 1 mg epinephrine (1 mL of 1:1000) in 250 mL D5W to yield 4 mcg/mL concentration. Infuse at 1-4 mcg/min initially (15-60 drops/min with microdrop apparatus), increasing to maximum 10 mcg/min 1

• For septic shock specifically: The FDA-approved dosing is 0.05-2 mcg/kg/min, titrated in increments of 0.05-0.2 mcg/kg/min every 10-15 minutes to achieve desired MAP 2

Pediatrics

Dosing: 0.1-1.0 mcg/kg/min, starting at the lowest dose and titrating to clinical effect. Doses up to 5 mcg/kg/min may be necessary in refractory cases 3

"Rule of 6" preparation method:

• Multiply 0.6 × body weight (kg) = number of mg epinephrine
• Dilute to total 100 mL normal saline
• Then 1 mL/h delivers 0.1 mcg/kg/min 1

Standard pediatric dose: 0.01 mg/kg (0.1 mL/kg of 1:10,000 solution; maximum 0.3 mg) for initial bolus dosing 1

Critical Indications and Timing

Epinephrine infusion should ONLY be initiated when:

1. Patient is profoundly hypotensive or in cardiac arrest
2. Failed to respond to IV volume replacement (1-2 L normal saline in adults at 5-10 mL/kg in first 5 minutes; up to 30 mL/kg in first hour for children) 1
3. Failed to respond to 2-3 intramuscular epinephrine injections (0.3-0.5 mg in adults, 0.01 mg/kg in children) 1

The rationale: IV epinephrine carries significant risk of potentially lethal arrhythmias, and IM epinephrine remains first-line treatment 1. Recent evidence suggests most patients respond to a single IM dose, making reflexive escalation to IV infusion unnecessary in many cases 4, 5.

Titration Strategy

Titrate based on:

• Blood pressure (target systolic >90 mmHg or MAP goal)
• Heart rate
• Oxygenation
• Signs of epinephrine toxicity (arrhythmias, severe hypertension, myocardial ischemia) 1

Adjustment frequency: Every 10-15 minutes in increments of 0.05-0.2 mcg/kg/min 2

Maximum rates:

• Adults: Up to 10 mcg/min (some sources suggest up to 2 mcg/kg/min for septic shock) 1, 2
• Pediatrics: Up to 5 mcg/kg/min in refractory cases 3

Monitoring Requirements

Continuous hemodynamic monitoring is ESSENTIAL and includes: 1

• Continuous cardiac monitoring (ECG)
• Blood pressure monitoring every 1 minute initially
• Pulse oximetry
• Ideally invasive arterial line monitoring in ICU/ED settings

However, lack of advanced monitoring should NOT preclude IV epinephrine use if deemed essential after failed IM injections—monitor by all available means (frequent manual BP, pulse, ECG if available). 1

Administration Considerations

Vascular access:

• Infuse into a large vein whenever possible 1, 2
• Avoid leg veins in elderly or those with occlusive vascular disease 2
• Avoid catheter tie-in technique (causes stasis and increased local drug concentration) 2
• Extravasation causes severe tissue necrosis—if occurs, inject phentolamine 0.1-0.2 mg/kg (up to 10 mg) diluted in 10 mL normal saline intradermally at site 3

Weaning Protocol

After hemodynamic stabilization, wean incrementally:

• Decrease doses every 30 minutes over 12-24 hours 2
• Continue monitoring for biphasic reactions (though most reactions are monophasic) 6, 5

Special Circumstances

Cardiac Arrest During Anaphylaxis

High-dose epinephrine with rapid escalation: 1

• Adults: 1-3 mg (1:10,000) IV over 3 minutes, then 3-5 mg IV over 3 minutes, then 4-10 mg/min infusion
• Pediatrics: 0.01 mg/kg (0.1 mL/kg of 1:10,000; max 0.3 mg) every 3-5 minutes, or start infusion up to 10 mg/min

Beta-Blocker Complication

Consider glucagon 1-5 mg IV over 5 minutes (20-30 mcg/kg in children, max 1 mg), followed by 5-15 mcg/min infusion, as epinephrine may be less effective 1

Refractory Hypotension

If epinephrine infusion insufficient, add dopamine 2-20 mcg/kg/min (400 mg in 500 mL D5W) titrated to maintain systolic BP >90 mmHg 1

Critical Safety Warnings

Absolute contraindications: None for anaphylaxis treatment 1, 6, 2

Major risks:

• Potentially lethal arrhythmias (ventricular fibrillation) 1, 2
• Acute severe hypertension and cerebral hemorrhage 2
• Myocardial ischemia/stress cardiomyopathy (even in young healthy patients) 7
• Pulmonary edema 2
• Coronary vasospasm 7

High-risk populations requiring careful balance:

• Elderly with multiple comorbidities
• Complex congenital heart disease
• Pulmonary hypertension
• Prior epinephrine-associated cardiomyopathy 6

Common pitfall: Inadvertent IV bolus administration of 1 mg epinephrine (intended for IM use) can cause catastrophic cardiovascular complications including multivessel coronary vasospasm and cardiomyopathy, even in young healthy individuals 8, 7. Always verify concentration: 1:10,000 (0.1 mg/mL) for IV use vs. 1:1000 (1 mg/mL) for IM use 3.

Adjunctive Therapies (Second-Line Only)

These should NEVER delay or replace epinephrine: 1, 9

• H1-antihistamines (diphenhydramine 1-2 mg/kg or 25-50 mg)
• H2-antagonists (ranitidine 1 mg/kg in children, 50 mg in adults)
• Glucocorticoids (methylprednisolone 1-2 mg/kg/day divided q6h)
• Inhaled beta-agonists for resistant bronchospasm