What is the immediate treatment for anaphylaxis?

From the Guidelines

The immediate treatment for anaphylaxis is epinephrine (adrenaline) administered as an intramuscular injection into the mid-outer thigh, with a standard dose of 0.3-0.5mg for adults and children weighing over 30kg, and 0.15mg for children under 30kg, as recommended by the most recent guidelines 1.

Key Points to Consider

• Epinephrine auto-injectors, such as EpiPen or Auvi-Q, are commonly used and the dose may be repeated every 5-15 minutes if symptoms persist 1.
• After administering epinephrine, call emergency services (911) immediately and transport the patient to an emergency department for further assessment and monitoring 1.
• The patient should lie flat with legs elevated unless they are having breathing difficulties, and additional treatments include removing the trigger if possible, administering oxygen if available, and providing antihistamines and corticosteroids as secondary medications (though these should not replace or delay epinephrine) 1.
• Epinephrine works rapidly to reverse the life-threatening symptoms of anaphylaxis by constricting blood vessels to increase blood pressure, relaxing airway muscles to improve breathing, and reducing hives and swelling 1.
• Even after symptoms improve, medical observation for 4-6 hours is necessary as biphasic reactions can occur 1.

Important Considerations

• Antihistamines and glucocorticoids are often used as adjunctive therapy, but should not be administered prior to, or in place of, epinephrine, as they have a slower onset of action and may not effectively treat acute symptoms 1.
• The use of glucocorticoids has been associated with reduced length of hospital stay, but has not been shown to prevent return visits to the ED following discharge, and their role in the acute management of anaphylaxis is limited 1.

From the FDA Drug Label

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 immediate treatment for anaphylaxis is epinephrine (IM), as it is indicated for the emergency treatment of allergic reactions, including anaphylaxis 2.

• The signs and symptoms of anaphylaxis include:
  • Flushing
  • Apprehension
  • Syncope
  • Tachycardia
  • Thready or unobtainable pulse associated with hypotension
  • Convulsions
  • Vomiting
  • Diarrhea and abdominal cramps
  • Involuntary voiding
  • Airway swelling
  • Laryngospasm
  • Bronchospasm
  • Pruritus
  • Urticaria or angioedema
  • Swelling of the eyelids, lips, and tongue

From the Research

Immediate Treatment for Anaphylaxis

The immediate treatment for anaphylaxis involves several key steps to ensure the patient's airway, breathing, and circulation are maintained. The primary treatment is:

• Intramuscular epinephrine, which is the first-line therapy for anaphylaxis, as it acts rapidly to relieve symptoms 3, 4, 5, 6
• In cases where the patient is in shock, intravenous epinephrine may be used, along with fluid resuscitation 3
• Airway obstruction must be recognized and addressed, with early intubation potentially necessary 3
• For shock that is refractory to epinephrine, additional vasopressors may be needed 3

Adjunct Medications

After epinephrine administration, adjunct medications may be considered, including:

• Histamine H1 and H2 antagonists
• Corticosteroids
• Beta2 agonists
• Glucagon 4

Importance of Early Treatment

Early treatment with epinephrine is critical to prevent a potentially fatal outcome, and delayed administration is a risk factor for fatal anaphylaxis 5, 6. The use of antihistamines and corticosteroids in anaphylaxis management is also explored, with data suggesting a beneficial effect of antihistamines, but the role of corticosteroids should be revisited 6.