From the FDA Drug Label
DOSAGE AND ADMINISTRATION Anaphylaxis: Adults and Children 30 kg (66 lbs) or more: 0.3 to 0.5 mg (0.3 to 0. 5 mL) intramuscularly or subcutaneously into anterolateral aspect of the thigh every 5 to 10 minutes as necessary
The dosage interval for 0.5mg epinephrine (intramuscular injection) in a severe asthmatic case, which can be considered as an anaphylactic reaction, is every 5 to 10 minutes as necessary 1.
From the Research
In severe asthma cases, 0.5mg of epinephrine can be administered intramuscularly every 5-15 minutes for up to 3 doses if needed, as supported by the most recent and highest quality study available 2.
Key Considerations
- The dosing applies to adults and children weighing over 30kg; children under 30kg should receive 0.01mg/kg up to a maximum of 0.3mg per dose.
- Epinephrine works rapidly by relaxing bronchial smooth muscles and reducing inflammation through its alpha and beta-adrenergic effects.
- However, it should be used cautiously in patients with cardiovascular disease, hypertension, hyperthyroidism, or diabetes due to potential side effects including increased heart rate, blood pressure elevation, and arrhythmias.
Monitoring and Additional Treatments
- After the initial injection, closely monitor the patient's response before giving subsequent doses.
- While administering epinephrine, continue other asthma treatments like oxygen, inhaled beta-agonists, and systemic corticosteroids.
- Always have cardiac monitoring available when giving repeated doses, and be prepared to manage potential cardiovascular side effects, as noted in studies such as 3 and 4.
Evidence Basis
- The most recent study 2 from 2024 provides insight into practice patterns for acute asthma exacerbation in adult patients admitted to U.S. intensive care units, highlighting the importance of adjunct interventions and their associations with outcomes.
- Although the provided studies do not directly address the administration frequency of epinephrine in severe asthma, the general principles of asthma management and the use of epinephrine in acute settings guide the recommendation, with older studies like 4 from 1992 discussing the use of intravenous adrenaline in severe acute asthma.