What is the recommended initial dose of intravenous (IV) adrenaline (epinephrine) for an adult patient experiencing anaphylaxis?

IV Adrenaline Dosing for Adult Anaphylaxis

For adults with anaphylaxis requiring IV adrenaline, administer an initial bolus of 50-100 mcg (0.5-1 mL of 1:10,000 solution) slowly over several minutes, repeated as needed, or initiate a continuous infusion at 1-4 mcg/min, titrating up to a maximum of 10 mcg/min based on clinical response. 1, 2

Critical Context: When IV Adrenaline is Indicated

IV adrenaline should only be used in specific high-risk scenarios, not as first-line therapy: 2

• Cardiac arrest from anaphylaxis 2, 3
• Profound hypotension unresponsive to multiple IM doses of adrenaline (typically 2-3 doses) and aggressive fluid resuscitation 1, 2
• Cardiovascular collapse despite appropriate initial management 4

IM adrenaline remains the first-line and preferred route for initial anaphylaxis treatment due to superior safety profile and lower risk of fatal arrhythmias. 2, 5

IV Bolus Dosing Protocol

Standard Adult Dose

• Initial dose: 50-100 mcg (0.5-1 mL of 1:10,000 solution = 0.1 mg/mL concentration) 3
• Administer slowly over several minutes 1
• Repeat as needed for persistent severe hypotension or bronchospasm 3

Cardiac Arrest Dosing

• Escalate rapidly to 1-3 mg (1:10,000) over 3 minutes 2, 3
• Follow with 3-5 mg over 3 minutes if no response 2, 3

IV Infusion Protocol

Preparation Method

Add 1 mg (1 mL) of 1:1000 adrenaline to 250 mL of D5W to yield a concentration of 4.0 mcg/mL. 1, 2

Alternative preparation: 1 mg (1 mL) in 100 mL of saline yields 1:100,000 solution (10 mcg/mL). 1

Infusion Rate

• Starting rate: 1-4 mcg/min (15-60 drops/min with microdrop apparatus) 1, 2, 3
• Titrate upward based on clinical response and side effects 1, 2
• Maximum rate: 10 mcg/min 1, 2, 3

If using infusion pump with 1:100,000 solution: 30-100 mL/h (5-15 mcg/min) initially, titrated to response. 1

Mandatory Safety Requirements

Concentration Verification

Always use 1:10,000 (0.1 mg/mL) for IV bolus administration. Using 1:1000 concentration IV can cause fatal arrhythmias. 2, 3 This is the most common and dangerous error in anaphylaxis management. 6

Monitoring Requirements

• Continuous cardiac monitoring is mandatory during IV administration 3
• Continuous hemodynamic monitoring when available (blood pressure every minute minimum) 1
• Monitor for arrhythmias, hypertension, and myocardial ischemia 1

Concurrent Essential Management

While administering IV adrenaline, simultaneously provide:

• Aggressive fluid resuscitation: 1-2 L normal saline bolus for adults at 5-10 mL/kg in first 5 minutes 1, 3
• High-flow oxygen with continuous pulse oximetry 1
• Supine positioning with legs elevated (unless respiratory distress precludes this) 1, 3

Adjunctive Medications (Secondary Priority)

These should never delay adrenaline but can be added after initial resuscitation: 4

• H1-antihistamine: Diphenhydramine 25-50 mg IV 2, 3
• H2-antihistamine: Ranitidine 50 mg IV or famotidine 20 mg IV 2, 3
• Corticosteroids: Methylprednisolone 1-2 mg/kg IV (typically 40 mg every 6 hours) to potentially prevent biphasic reactions, though no acute benefit 2, 3

Special Population: Beta-Blocker Patients

For patients on beta-blockers with refractory hypotension despite adrenaline and fluids:

Administer glucagon 1-5 mg IV over 5 minutes, followed by infusion at 5-15 mcg/min. 2, 3 Glucagon bypasses beta-receptor blockade and can restore cardiovascular responsiveness. 3

Critical Pitfalls to Avoid

• Using wrong concentration: 1:1000 (1 mg/mL) IV instead of 1:10,000 causes life-threatening arrhythmias 2, 3
• Administering IV adrenaline as first-line: IM route is safer and preferred initially; IV is reserved for refractory cases 2, 5
• Inadequate monitoring: IV adrenaline without cardiac monitoring risks undetected fatal arrhythmias 1, 3
• Insufficient fluid resuscitation: Up to 50% of intravascular volume can shift to extravascular space within 10 minutes; aggressive crystalloid replacement (up to 7 L may be needed) is essential 1
• Delaying repeat dosing: If hypotension persists, repeat boluses or increase infusion rate rather than accepting inadequate response 1, 2

Why IM Remains Preferred for Initial Treatment

IM adrenaline in the anterolateral thigh achieves peak plasma concentrations in 8±2 minutes versus 34±14 minutes with subcutaneous injection, providing rapid therapeutic effect with significantly lower risk of dosing errors and cardiac complications compared to IV administration. 2, 5 The standard IM dose is 0.3-0.5 mg (maximum 0.5 mg) of 1:1000 solution, repeated every 5-15 minutes as needed. 2, 3, 4