I need a prescription for epinephrine; what dose should I get?

Neffy Epinephrine Prescription Dosing

For epinephrine autoinjector prescriptions, prescribe the 0.15 mg dose for patients weighing 7.5-25 kg (16.5-55 lbs) and the 0.3 mg dose for patients weighing 25 kg (55 lbs) or more. 1

Weight-Based Dosing Algorithm

For Patients Weighing 7.5-25 kg (16.5-55 lbs)

• Prescribe 0.15 mg epinephrine autoinjector 1
• This dose provides optimal coverage for children weighing 15 kg (33 lbs) 1
• For infants weighing ≤7.5 kg, the 0.15 mg dose represents a twofold overdose, but this is preferable to the delay and dosing errors associated with drawing up epinephrine from vials 1
• Most pediatricians (80%) prescribe the 0.15 mg autoinjector for infants weighing 10 kg (22 lbs), as the alternative vial/syringe/needle technique can take 3-4 minutes and frequently results in inaccurate or zero dosing 1

For Patients Weighing 25-30 kg (55-66 lbs): Transition Zone

• Switch to 0.3 mg epinephrine autoinjector when patients reach 25-30 kg body weight 1
• At 25 kg, the 0.15 mg dose provides a 1.7-fold underdose, while the 0.3 mg dose provides only a 1.2-fold overdose 1
• A small overdose in a healthy child carries lower risk than an underdose during anaphylaxis 1

For Patients Weighing ≥30 kg (66 lbs)

• Prescribe 0.3 mg epinephrine autoinjector 1
• This provides optimal dosing for most children and adults in this weight range 1
• The FDA-approved dose for adults and children ≥30 kg is 0.3-0.5 mg intramuscularly 2

Critical Prescribing Considerations

Always Prescribe Two Autoinjectors

• All patients at risk for anaphylaxis should carry 2 epinephrine autoinjectors, as 6-19% of pediatric patients require a second dose 1, 3
• Subsequent doses may be needed at 5-20 minute intervals for severe or rapidly progressive anaphylaxis 1

Administration Technique Matters

• Instruct patients to inject into the anterolateral aspect of the thigh (vastus lateralis muscle) 2
• Never inject into buttocks, digits, hands, or feet 2
• Proper injection technique with compression of soft tissue improves drug delivery regardless of BMI 4

Who Should Receive Prescriptions

• Patients with a history of anaphylaxis who may re-encounter triggers 1
• Patients with idiopathic anaphylaxis 1
• Consider prescribing for patients with known sensitization to peanut, tree nuts, cow's milk, crustacean shellfish, and fish, even without prior anaphylaxis, as these allergens are associated with severe and fatal reactions 1

Common Pitfalls to Avoid

Do Not Recommend Vial/Syringe/Needle for Infants

• Drawing epinephrine from vials takes laypersons 3-4 minutes and frequently results in inaccurate dosing or complete loss of the dose 1
• Prefilled syringes degrade within months due to air exposure 1
• The favorable benefit-to-risk ratio of epinephrine supports using the 0.15 mg autoinjector even in small infants, despite modest overdosing 1

Do Not Delay Switching to Higher Dose

• Failure to switch from 0.15 mg to 0.3 mg at appropriate weight (25-30 kg) results in significant underdosing during critical anaphylactic events 1

Serious Adverse Effects Are Rare

• Pharmacologic effects (pallor, tremor, anxiety, palpitations) are expected and similar to endogenous "fight or flight" response 1
• There is no absolute contraindication to epinephrine in anaphylaxis 1
• Serious adverse effects from intramuscular epinephrine are rare in children 1