From the Guidelines
For anaphylaxis in adults, the first-line treatment is epinephrine (adrenaline) administered as an intramuscular injection at a dose of 0.01 mg/kg of a 1:1000 solution, up to a maximum of 0.5 mg in adults, as recommended by the most recent and highest quality study 1.
Anaphylaxis Treatment
The dose of epinephrine should be administered intramuscularly into the anterolateral thigh, and can be repeated every 5-15 minutes if symptoms persist or worsen.
- Patients with known anaphylaxis risk should carry an epinephrine auto-injector, which delivers a dose of epinephrine.
- After administering epinephrine, the patient should be placed in a supine position with legs elevated unless they are experiencing respiratory distress.
- Additional supportive measures include administering oxygen (if available), establishing IV access for fluid resuscitation with normal saline, and using adjunctive medications such as antihistamines and corticosteroids.
Importance of Epinephrine
Epinephrine works rapidly by constricting blood vessels, increasing blood pressure, relaxing airway muscles, and reducing inflammation, making it the most effective treatment for the potentially life-threatening symptoms of anaphylaxis, as supported by the study 1.
Monitoring and Follow-up
Even after symptoms resolve, patients should be monitored for at least 4-6 hours due to the risk of biphasic reactions, as suggested by the study 1.
- The study 1 also recommends extended clinical observation in a setting capable of managing anaphylaxis for patients with resolved severe anaphylaxis and/or those who need more than one dose of epinephrine.
- Antihistamines and glucocorticoids are often used as adjunctive therapy, but they should not be administered before or in place of epinephrine, as they have no proven role in the treatment of acute anaphylaxis, as stated in the study 1.
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 anaphylaxis dose in adults is 0.3 to 0.5 mg (0.3 to 0.5 mL) intramuscularly or subcutaneously into the anterolateral aspect of the thigh every 5 to 10 minutes as necessary 2.
- The dose can be repeated as necessary.
- It is essential to administer the dose intramuscularly or subcutaneously into the anterolateral aspect of the thigh.
From the Research
Anaphylaxis Dose in Adults
- The initial recommended adult dose of epinephrine for anaphylaxis is 0.3-0.5 mg, injected intramuscularly in the anterolateral aspect of the mid-thigh 3, 4.
- This dose can be administered using an epinephrine auto-injector, which is available in different doses, including 0.15,0.30, and 0.50 mg 5.
- The administration of epinephrine should be immediate upon evidence of anaphylaxis, as delays can be fatal 3, 6, 4, 5.
- The use of epinephrine auto-injectors has been recommended for patients with known anaphylactic reactivity, and education on proper use is crucial 4, 5.
Administration Route and Timing
- Intramuscular administration in the anterolateral thigh is the recommended route for epinephrine injection in adults 3, 6, 4.
- The onset of action of epinephrine is rapid, with maximal pharmacodynamic effect within 10 minutes of intramuscular administration 5.
- Prompt administration of epinephrine is critical, and any delays can result in increased morbidity and mortality 3, 6, 4, 5.