Quick Answer
Short answer: An EpiPen may fail to work due to expiring adrenaline, incorrect administration technique, or failure to inject into the correct muscle. Incomplete or improper use can result in inadequate adrenaline delivery, which is critical for reversing anaphylaxis.
Adrenaline Expiration and Storage
Adrenaline in EpiPens has a limited shelf life, typically two years from the date of manufacture. If the EpiPen is more than two years old, or has been stored improperly, the adrenaline may degrade, rendering the device ineffective. Always check the EpiPen for expiration dates and store it at room temperature between 59°F and 86°F (15°C and 30°C).
Incorrect Administration Technique
Administering an EpiPen incorrectly can lead to ineffective adrenaline delivery. Hold the device at a 90-degree angle against the outer thigh, with the tip pointing towards the middle of the leg. Press the device firmly against the skin for about 10 seconds until the needle is fully inserted. Do not rub or massage the area after injecting.
Incorrect Injection Site or Muscle
The EpiPen should be injected into the mid-outer thigh, about 2.5 cm (1 inch) below the top of the thigh. Injecting into the wrong muscle or site can result in inadequate adrenaline delivery. If injected too high, the adrenaline may not reach the bloodstream effectively, while injecting too low may cause unnecessary bleeding.
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