Should I prescribe an EpiPen (epinephrine auto-injector) to this patient?

Should You Prescribe an EpiPen?

Yes, prescribe an epinephrine auto-injector (EpiPen) if the patient has a history of anaphylaxis to a trigger they may encounter outside a medical setting, or if they have experienced generalized acute urticaria after an insect sting. 1, 2

Primary Indications for Prescription

Prescribe self-injectable epinephrine for patients with:

• Previous anaphylaxis with respiratory or cardiovascular compromise to a trigger that may be re-encountered outside the hospital 1
• Generalized acute urticaria after an insect sting (approximately 10% risk of more severe reaction from future stings) 1
• Idiopathic anaphylaxis (uncommon in children) 1

High-Risk Factors That Strengthen the Indication

Consider prescribing even with less severe prior reactions if the patient has:

• Concurrent asthma 1
• Previous reactions to high-risk foods (peanut, tree nut, seafood, milk, egg) 1
• Reaction to trace allergen exposure 1
• Poor access to emergency services 1
• Lack of adequate supervision 1
• Use of nonselective β-blockers 1

Critical Dosing Guidelines

For children weighing <30 kg: Prescribe 0.15 mg dose (EpiPen Jr) 3

For patients weighing ≥30 kg: Prescribe 0.3 mg dose (EpiPen) 3

Always prescribe TWO auto-injectors because approximately 10-20% of patients require more than one dose 3

Special Dosing Considerations for Infants and Small Children

For children weighing 10-15 kg: The 0.15 mg autoinjector provides 1.5-fold overdose, but this is preferable to the delay and dosing errors associated with ampule/syringe/needle technique 1

For children weighing <10 kg: Evaluate the risk of 1.5-fold overdose versus the documented problems with ampule/syringe/needle (parents took 142±13 seconds vs. 29 seconds for emergency nurses, with nearly 40-fold variation in dose accuracy) 1

The evidence shows that most pediatricians (80-100%) prescribe the 0.15 mg autoinjector for children weighing 10-15 kg despite the overdose, because the certainty of delivery outweighs the risk of modest overdose in healthy children 1

Why Epinephrine Is Non-Negotiable

Intramuscular epinephrine is the ONLY first-line treatment for anaphylaxis 2, 4

• There are no absolute contraindications to epinephrine in anaphylaxis, even in patients with cardiac disease or advanced age 1, 2
• Antihistamines and bronchodilators should never be relied upon as primary treatment—only epinephrine addresses life-threatening cardiovascular and respiratory manifestations 2
• Delay in administering epinephrine is associated with anaphylaxis fatalities 2

Administration Instructions to Provide

Inject into the anterolateral aspect of the mid-thigh (vastus lateralis muscle) because this achieves peak plasma concentrations in 8±2 minutes, compared to 34±14 minutes with subcutaneous deltoid injection 5, 3

The dose can be administered through clothing if necessary 3

Repeat every 5-10 minutes if symptoms persist or worsen 3

Call 911 immediately after administering epinephrine, even if symptoms improve 5, 2

Common Pitfalls to Avoid

Do NOT prescribe ampule/syringe/needle for infants <15 kg unless absolutely necessary—the data shows parents take significantly longer (142 seconds vs. 29 seconds for emergency nurses) and have nearly 40-fold variation in dose accuracy (0.004 to 0.151 mL when asked to draw 0.09 mL) 1

Do NOT underprescribe—recognize that approximately 70% of anaphylaxis cases have respiratory symptoms and only 10% have cardiovascular symptoms initially, but skin manifestations (urticaria, angioedema, flushing) occur in >80% 1

Do NOT assume patients will recognize anaphylaxis—even trained healthcare professionals underrecognize it 1

Ensure patients understand that epinephrine side effects (pallor, tremor, anxiety, palpitations) can mimic anaphylaxis symptoms and should not prompt unnecessary repeat dosing 1

FDA Safety Considerations

Injection site: The anterolateral thigh is the most appropriate location due to muscle size and blood flow; do NOT inject into deltoid, buttock, digits, hands, or feet 6

Infection risk: Rare cases of necrotizing fasciitis and gas gangrene have been reported, particularly with buttock injection; advise patients to seek care if they develop persistent redness, warmth, swelling, or tenderness at injection site 6

Disease interactions: Administer with caution (but still administer) in patients with heart disease, hyperthyroidism, Parkinson's disease, diabetes, or those on cardiac glycosides, β-blockers, or MAOIs 6