What is the dose of epinephrine (adrenaline) for anaphylaxis in adults?

From the Guidelines

For anaphylaxis in adults, the first-line treatment is epinephrine (adrenaline) 0.01 mg/kg of a 1:1000 solution, up to a maximum of 0.5 mg, administered intramuscularly in the anterolateral thigh. This dose can be repeated every 5-15 minutes if symptoms persist or worsen 1. The administration of epinephrine is crucial in the treatment of anaphylaxis, and it is essential to prioritize its use over other medications such as antihistamines and corticosteroids, which should not be administered before or in place of epinephrine 1.

Some key points to consider when treating anaphylaxis in adults include:

• The use of auto-injectors like EpiPen or Auvi-Q, which typically deliver 0.3 mg per dose for adults 1
• The importance of placing the patient in a supine position with legs elevated unless they are experiencing respiratory distress 1
• The use of supplemental treatments such as oxygen (if available), intravenous fluids for hypotension, and second-line medications like antihistamines (diphenhydramine 25-50 mg IV/IM) and corticosteroids (methylprednisolone 125 mg IV) 1
• The need for patients to seek emergency medical care even after symptoms resolve, as biphasic reactions can occur hours later, and observation for at least 4-6 hours is recommended 1

It is also important to note that the risk factors for severe anaphylaxis include cardiovascular disease, asthma, older age, and additional coexisting, comorbid conditions 1. Medications and stinging insects are the leading triggers in adults, and food allergy impacts 8% to 11% of children and adults in the United States 1.

In terms of the evidence, the most recent and highest quality study is from 2024, which provides a strong recommendation for the use of epinephrine in the treatment of anaphylaxis 1. This study also highlights the importance of educating patients and their caregivers about the signs and symptoms of anaphylaxis and the use of epinephrine in emergency situations.

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.
• Another study recommends a dose of 0.01 mg/kg (up to 0.5 mg in adults) intramuscularly (IM) in the anterolateral thigh 4.
• Epinephrine auto-injectors are available with weight-appropriate doses of 0.15,0.30, and 0.50 mg, and different needle lengths are available for pediatric and adult patients, especially obese patients to ensure intramuscular delivery in the thigh 5.

Administration Route

• Intramuscular administration is the preferred route for epinephrine in anaphylaxis, as it has a more satisfactory therapeutic window compared to subcutaneous or intravenous routes 3.
• Intravenous epinephrine administration is recommended in patients refractory to IM epinephrine and IV fluids, or those with cardiovascular collapse 4.

Importance of Prompt Administration

• Failure to inject epinephrine promptly contributes to anaphylaxis fatalities 3.
• Education about anaphylaxis and prompt treatment are critical for patients and their caregivers 5.
• Delaying epinephrine administration can result in unnecessary increases in patient morbidity and mortality 6.