What are the guidelines for prescribing EpiPen (epinephrine) to a patient with a history of severe allergic reactions, considering age, weight, and underlying medical conditions?

How to Prescribe an EpiPen

Prescribe an EpiPen for any patient with a history of anaphylaxis involving respiratory or cardiovascular symptoms, or for high-risk patients with confirmed food/insect venom allergies combined with risk factors such as asthma, remote location, or beta-blocker use. 1

Who Needs an EpiPen

Absolute Indications

• Any patient with prior anaphylaxis characterized by respiratory compromise (shortness of breath, wheeze, throat tightness) or cardiovascular symptoms (hypotension, weak pulse, dizziness, syncope) 1, 2
• Children with generalized acute urticaria after insect stings, as they have approximately 10% risk of more severe future reactions 1
• Patients with confirmed food or insect venom allergies who have additional risk factors (see below) 1

High-Risk Factors That Lower the Threshold

• Asthma requiring preventer medication - these patients are at higher risk of fatal anaphylaxis 1
• Remote location away from immediate medical care 1
• Use of nonselective β-blockers 1

Dosing by Weight

Weight-Based Selection

• Children 10-25 kg: EpiPen Jr (0.15 mg) 1, 2
• Children ≥25 kg and adults: EpiPen (0.3 mg) 1, 2
• Adults and children ≥30 kg: 0.3-0.5 mg per FDA labeling 3

Critical Dosing Caveat

Infants and children <15 kg, especially those ≤7.5 kg, present a clinical dilemma - the lowest available EpiPen Jr dose (0.15 mg) may be too high for many infants and some young children. 1, 2 Despite this concern, the benefit of having epinephrine available outweighs the risk of slight overdosing in life-threatening anaphylaxis. 4

How Many to Prescribe

Always prescribe TWO EpiPens - approximately 6-19% of patients require a second dose, and the second dose may be needed before emergency services arrive. 1

Patient Education Requirements (Non-Negotiable)

You must provide the following at the time of prescription:

• Written, personalized anaphylaxis emergency action plan that includes specific symptoms to watch for (mouth/throat itching or swelling, skin hives, gut cramping/vomiting, lung symptoms like wheeze or shortness of breath, heart symptoms like weak pulse or dizziness) 5, 1
• Training on injection technique - inject into the anterolateral thigh (vastus lateralis), NOT buttocks, digits, hands, or feet 3
• Instructions to inject at first signs of anaphylaxis, particularly with respiratory or cardiovascular symptoms 1
• Mandate to call 911 immediately after any EpiPen use and seek emergency department assessment 1
• Education on allergen avoidance specific to their trigger 2
• Plan for monitoring autoinjector expiration dates 2

Critical Teaching Points

• Antihistamines and asthma inhalers CANNOT be depended on in anaphylaxis - epinephrine is the only first-line treatment 5, 4
• Patients should self-carry and self-administer epinephrine 5
• Epinephrine may be repeated every 5-15 minutes if symptoms persist or recur 2, 3
• All patients who use epinephrine must go to the emergency department for 4-6 hours observation minimum, as biphasic reactions can occur in 1-20% of cases up to 72 hours later 2

Special Populations

Pregnancy

Epinephrine is safe and indicated for pregnant patients - maternal hypoxia poses a greater fetal risk than epinephrine administration. 6 However, note that epinephrine may result in uterine vasoconstriction and decreased uterine blood flow. 3

Patients on Beta-Blockers

These patients may require glucagon 1-2 mg IV as rescue medication if epinephrine fails, as epinephrine may be less effective in beta-blocked patients. 6 This doesn't change the prescription - still prescribe the EpiPen, but document this risk and ensure the patient understands the need for immediate emergency care.

Elderly Patients

Consider that geriatric patients may be particularly sensitive to epinephrine effects, but this should not prevent prescription for appropriate indications. 3

School and Workplace Considerations

• Inform school personnel about the child's anaphylaxis history and specific allergens 5
• Ensure allergen-free environment at mealtime 5
• Provide written response plan to school that can be initiated immediately 5
• Children with food allergies are covered by the Americans with Disabilities Act, which facilitates emergency medical response arrangements 5

Common Pitfalls to Avoid

• Don't delay prescription waiting for "severe enough" reactions - prescribe based on risk factors, not just prior severity 1
• Don't prescribe only one EpiPen - always prescribe two 1
• Don't forget the written action plan - verbal instructions alone are insufficient 1, 2
• Don't assume patients will know when to use it - explicitly teach them to use it for respiratory or cardiovascular symptoms, not just skin symptoms 1
• Don't forget to arrange allergy specialist referral for further evaluation and long-term management 2