What is the recommended dose and administration of epinephrine (adrenaline) for the treatment of angioedema?

Epinephrine Dosage and Administration for Angioedema

For angioedema treatment, epinephrine should be administered at 0.3-0.5 mg (0.3-0.5 mL of 1:1000 solution) intramuscularly in the anterolateral thigh for adults, and 0.01 mg/kg (maximum 0.3 mg) for children under 30 kg, repeated every 5-10 minutes as necessary. 1, 2

Administration Route and Dosing

Adults and Children ≥30 kg:

• Dose: 0.3-0.5 mg (0.3-0.5 mL of 1:1000 solution)
• Route: Intramuscular (preferred) or subcutaneous injection into anterolateral thigh
• Frequency: May repeat every 5-10 minutes as necessary 2

Children <30 kg:

• Dose: 0.01 mg/kg (0.01 mL/kg of 1:1000 solution), maximum 0.3 mg (0.3 mL)
• Route: Intramuscular (preferred) or subcutaneous injection into anterolateral thigh
• Frequency: May repeat every 5-10 minutes as necessary 2

Alternative Administration for Specific Scenarios:

• For orolingual angioedema associated with IV alteplase: If angioedema increases after standard treatments, administer epinephrine (0.1%) 0.3 mL subcutaneously or by nebulizer 0.5 mL 3

Important Considerations

Efficacy by Angioedema Type:

• Epinephrine is first-line therapy for allergic/histamine-mediated angioedema 1
• Epinephrine is not efficacious for hereditary angioedema (HAE) and is not recommended as primary treatment 3
• Epinephrine may have limited efficacy in ACE inhibitor-induced angioedema and could potentially cause harm in these patients 4

Administration Technique:

• Use a needle long enough (at least 1/2 inch to 5/8 inch) to ensure intramuscular delivery 2
• Do not administer repeated injections at the same site to avoid tissue necrosis from vasoconstriction 2
• When administering to children, hold the leg firmly in place to minimize risk of injection-related injury 2

Monitoring:

• Monitor patients clinically for severity of allergic reaction and potential cardiac effects 2
• Observe for signs of response and prepare for additional doses if symptoms persist 1
• Monitor vital signs, including blood pressure, heart rate, and oxygen saturation 1

Additional Management

Supportive Care:

• Maintain airway; endotracheal intubation may be necessary if edema involves larynx, palate, floor of mouth, or oropharynx 3
• Position patients with hypotension in supine position with legs elevated 1
• Administer oxygen for respiratory symptoms 1

Adjunctive Medications:

• H1 antihistamines (diphenhydramine 50 mg IV) for cutaneous symptoms 1
• H2 blockers (ranitidine 50 mg IV or famotidine 20 mg IV) 3, 1
• Corticosteroids (IV methylprednisolone 125 mg) 3

Cautions and Contraindications

• Epinephrine may induce myocardial ischemia or dysrhythmia, particularly in patients with underlying heart disease 4
• Use with caution in patients with hyperthyroidism, Parkinson's disease, diabetes, and pheochromocytoma 2
• For ACE inhibitor-induced angioedema, consider alternative treatments as epinephrine may not be effective 4, 5

Special Considerations for Different Types of Angioedema

• For hereditary angioedema: Fresh frozen plasma, C1 esterase inhibitor, or icatibant (30 mg subcutaneously) may be more effective than epinephrine 3
• For ACE inhibitor-induced angioedema: Consider fresh frozen plasma if refractory to standard treatment 5
• For angioedema associated with IV alteplase: Follow specific protocol including discontinuation of alteplase, administration of methylprednisolone, diphenhydramine, and ranitidine before considering epinephrine 3

By following these guidelines for epinephrine administration in angioedema, clinicians can optimize patient outcomes while minimizing potential adverse effects from inappropriate treatment.