From the Guidelines
The standard EpiPen contains epinephrine at a concentration of 1:1000 (1 mg/mL), with adult EpiPens delivering 0.3 mg and EpiPen Jr delivering 0.15 mg per dose. This concentration is specifically formulated to provide rapid absorption when administered intramuscularly during severe allergic reactions or anaphylaxis, as recommended by the NIAID-sponsored expert panel 1. The 1:1000 concentration allows for a relatively small volume of medication (0.3 mL for adults, 0.15 mL for children) to deliver an effective dose, making the auto-injector practical for emergency use.
Epinephrine works by constricting blood vessels to increase blood pressure, relaxing smooth muscles in the lungs to improve breathing, and reducing swelling and hives, as described in the guidelines for the diagnosis and management of food allergy in the United States 1. The concentration is carefully calibrated to provide these life-saving effects while minimizing potential side effects such as increased heart rate, tremors, and anxiety that can occur with epinephrine administration.
Some key points to consider when using an EpiPen include:
- Administering the epinephrine intramuscularly in the anterolateral thigh, as recommended by the guidelines 1
- Using the correct dose, with 0.15 mg for children weighing 10-25 kg and 0.3 mg for individuals weighing over 25 kg 1
- Being aware that epinephrine doses may need to be repeated every 5-15 minutes if symptoms persist or worsen 1
- Storing EpiPens at room temperature, away from light, and being aware of their limited shelf life (typically 12-18 months)
Overall, the 1:1000 concentration of epinephrine in EpiPens is a crucial component of emergency treatment for severe allergic reactions and anaphylaxis, and its use should be guided by the most recent and highest-quality evidence, such as the NIAID-sponsored expert panel guidelines 1.
From the FDA Drug Label
11 DESCRIPTION Adrenalin® (epinephrine injection, USP) is a clear, colorless, sterile solution containing 1 mg/mL epinephrine, packaged as 1 mL of solution in a single-use clear glass vial or 30 mL of solution in a multiple-dose amber glass vial.
The concentration of EpiPen (epinephrine) is 1 mg/mL.
- The EpiPen contains epinephrine at a concentration of 1 mg per 1 mL of solution 2.
From the Research
EpiPen Concentration
- The recommended dose of epinephrine in anaphylaxis is 0.01-mg/kg, with a maximum dose of 0.3-0.5 mg 3.
- This dose is based on limited pharmacokinetic data in healthy volunteers, and there is a need for more research on epinephrine pharmacodynamics in children and adults in anaphylaxis 3.
- Epinephrine auto-injectors (EAIs) are available in different doses, including 0.15 mg and 0.3 mg, and the choice of dose depends on the patient's weight 3.
- A newly available 0.1 mg EAI has a lower dose and shorter needle, making it more suitable for patients weighing 7.5 to 15 kg 3.
Availability of Epinephrine Auto-Injectors
- EAIs are only available in 60% of countries surveyed, mainly in high-income countries 4.
- Many countries in South America, Africa/Middle-East, and Asian-Pacific regions do not have EAIs available, or depend on individual importation 4.
- National policies regarding the availability of EAIs in public settings are limited to few countries (16%) 4.
Administration of Epinephrine
- Intramuscular epinephrine is the first-line treatment for anaphylaxis, and EAIs are preferred by healthcare providers for their ease of use and convenience 5.
- The autoinjector method is rated more favorably for time required for training, ease of use, convenience, satisfaction with weight-based dosing, risk of dosing errors, and speed of administration 5.
- However, manual injection use is rated more favorably for risk of provider self-injury and patient cost 5.