What is the epinephrine (Epi) dose for a severe asthma exacerbation?

Epinephrine Dosing for Severe Asthma Exacerbation

For severe asthma exacerbations, epinephrine can be administered at 0.3 to 0.5 mg (0.3 to 0.5 mL of 1:1000 solution) intramuscularly into the anterolateral thigh for adults and children ≥30 kg, or 0.01 mg/kg (up to 0.3 mg) for children <30 kg, repeated every 5-10 minutes as necessary. 1

Administration Routes and Dosing

Intramuscular (IM) Administration (Preferred)

• Adults and children ≥30 kg (66 lbs):

  • 0.3 to 0.5 mg (0.3 to 0.5 mL of 1:1000 solution)
  • Inject into anterolateral aspect of the thigh
  • May repeat every 5-10 minutes as necessary 1

• Children <30 kg (66 lbs):

  • 0.01 mg/kg (0.01 mL/kg), maximum 0.3 mg (0.3 mL)
  • Inject into anterolateral aspect of the thigh
  • May repeat every 5-10 minutes as necessary 1

Alternative Routes in Life-Threatening Cases

While the FDA label primarily addresses IM/SC administration, case reports suggest that in life-threatening asthma not responding to standard treatments, intravenous (IV) epinephrine may be considered. A retrospective study of 27 adults with life-threatening asthma showed no significant adverse effects from IV epinephrine 2. However, this should be reserved for extreme cases under close monitoring.

Important Considerations

Precautions

• Do not inject into buttocks, digits, hands, or feet 1
• Use with caution in patients with:
  • Underlying heart disease (risk of ventricular arrhythmias)
  • Hyperthyroidism
  • Parkinson's disease
  • Diabetes
  • Pheochromocytoma 1

Monitoring

• Monitor for common adverse reactions:
  • Anxiety, restlessness, tremor, weakness, dizziness
  • Sweating, palpitations, pallor
  • Nausea, vomiting, headache
  • Respiratory difficulties
  • Arrhythmias and blood pressure changes 1

Age Considerations

• Epinephrine appears to be safe in older asthmatics without recent myocardial infarction or angina 3
• Elderly patients may be at greater risk of adverse reactions 1

Treatment Algorithm

1. First-line treatments:

   • Nebulized short-acting beta-agonists (e.g., salbutamol)
   • Systemic corticosteroids
   • Consider adding ipratropium bromide for severe cases 4

2. When to consider epinephrine:

   • Failure to respond to first-line treatments 5
   • Life-threatening presentation with severe respiratory distress
   • Impending respiratory failure

3. Administration sequence:

   • Administer appropriate dose based on weight
   • Monitor response closely
   • Repeat dose every 5-10 minutes if necessary 1
   • Consider alternative treatments if inadequate response after 2-3 doses

Clinical Pearls

• Epinephrine should be considered when standard treatments fail in severe asthma exacerbations 5
• Multiple studies support the safety of epinephrine in asthma exacerbations, even in older adults without cardiac contraindications 3
• The presence of sulfite in epinephrine products should not deter use in life-threatening situations 1
• Repeated injections of epinephrine may be necessary to sustain bronchodilation, but a single injection of longer-acting epinephrine preparations may be equally effective with fewer side effects 6