From the Guidelines
Immediate treatment of anaphylaxis requires prompt administration of epinephrine (adrenaline) as the first-line therapy, with a dose of 0.01 mg/kg of a 1:1000 (1 mg/mL) solution to a maximum of 0.5 mg in adults and 0.3 mg in children, administered intramuscularly into the anterolateral thigh 1.
Key Considerations
- The dose of epinephrine can be repeated every 5-15 minutes if symptoms persist.
- After epinephrine administration, the patient should be placed in a supine position with legs elevated unless respiratory distress is present.
- Supplemental oxygen should be provided if available, and IV access should be established for fluid resuscitation with normal saline or Ringer's lactate to counter hypotension.
Second-Line Medications
- Antihistamines, such as diphenhydramine, can be used to relieve urticaria and itching, but should not be administered before or in place of epinephrine 1.
- Corticosteroids, such as methylprednisolone, may help prevent biphasic reactions, but have a slow onset of action and limited role in acute management 1.
- Bronchodilators, such as albuterol, can be added for persistent bronchospasm.
Post-Treatment Care
- Patients should be observed for 4-8 hours due to the risk of biphasic reactions.
- An epinephrine auto-injector should be prescribed for future emergencies.
Important Notes
- Epinephrine is the cornerstone of anaphylaxis management and should be administered promptly, as it has a faster onset of action and more robust pharmacologic action compared to antihistamines and glucocorticoids 1.
- Antihistamines and glucocorticoids should not be used as a substitute for epinephrine, but may have an adjunct role in treatment after epinephrine has been administered 1.
From the FDA Drug Label
1 INDICATIONS & USAGE Adrenalin® is available as a single-use 1 mL vial and a multiple-use 30 mL vial for intramuscular and subcutaneous use. Emergency treatment of allergic reactions (Type I), including anaphylaxis, which may result from allergic reactions to insect stings, biting insects, foods, drugs, sera, diagnostic testing substances and other allergens, as well as idiopathic anaphylaxis or exercise-induced anaphylaxis.
The treatment for anaphylaxis is epinephrine (IM), specifically Adrenalin® administered via intramuscular or subcutaneous use 2.
- Key points:
- Emergency treatment for allergic reactions, including anaphylaxis
- Administered via intramuscular or subcutaneous use
- Available as a single-use 1 mL vial and a multiple-use 30 mL vial
From the Research
Treatment for Anaphylaxis
The treatment for anaphylaxis typically involves the administration of epinephrine, which is considered the mainstay of acute pharmacotherapy for this complication 3, 4, 5. The key aspects of anaphylaxis treatment are:
- Removal of the trigger or allergen
- Administration of epinephrine via intramuscular injection, typically in the lateral portion of the thigh 3, 4, 5
- Supportive care for the patient's airway, breathing, and circulation
- Monitoring for potential biphasic reactions
Epinephrine Administration
Epinephrine is usually administered using an autoinjector, with a dose of 0.01 mg/kg (1:1000) for adults and children 4. The maximum single dose of epinephrine is 0.5 mg, and it may be repeated after 5-10 minutes if needed 4. The method of choice for administering epinephrine is by intramuscular injection with an autoinjector, except in intensive-care medicine 3.
Adjunct Medications
After epinephrine administration, adjunct medications such as histamine H1 and H2 antagonists, corticosteroids, beta2 agonists, and glucagon may be considered 5. However, these should only be used after epinephrine has been administered.
Barriers to Treatment
Despite the importance of epinephrine in treating anaphylaxis, there are barriers to its use, including inadequate patient education and the high cost of autoinjectors 6. Alternative routes of epinephrine administration, such as intranasal, sublingual, inhaled, and needle-free intramuscular administration, are being investigated as potential alternatives to intramuscular injection 7.