What is the recommended intramuscular (IM) dosing for epinephrine in adults and children over 12 years?

Intramuscular Epinephrine Dosing

For adults and children over 12 years, administer 500 mcg (0.5 mL of 1:1000 solution) intramuscularly into the anterolateral thigh, repeated every 5-10 minutes as necessary. 1, 2

Standard IM Dosing by Age and Weight

Adults and Children ≥30 kg (66 lbs)

• Dose: 0.3-0.5 mg (0.3-0.5 mL of 1:1000 solution) intramuscularly into the anterolateral thigh 2
• Maximum single dose: 0.5 mg (0.5 mL) 2
• Repeat every 5-10 minutes as clinically indicated 2

Children >12 years (if small body habitus)

• Dose: 300 mcg (0.3 mL of 1:1000 solution) if the child appears small for age 1
• This recognizes that some adolescents may weigh less than 30 kg 1

Children <30 kg (66 lbs)

• Dose: 0.01 mg/kg (0.01 mL/kg of 1:1000 solution) intramuscularly 2
• Maximum single dose: 0.3 mg (0.3 mL) 2
• Repeat every 5-10 minutes as necessary 2

Critical Administration Technique

Site of Injection

• Always inject into the anterolateral aspect of the mid-thigh 2, 3
• This site provides superior absorption compared to subcutaneous or other intramuscular sites 3
• Can inject through clothing if necessary in emergency situations 2
• Never inject into buttocks, digits, hands, or feet due to risk of tissue necrosis from vasoconstriction 2

Needle Considerations

• Use a needle at least 1/2 to 5/8 inch long to ensure intramuscular (not subcutaneous) delivery 2
• Intramuscular administration has faster onset than subcutaneous injection 3

Repeat Dosing

• Do not administer repeated injections at the same site to avoid tissue necrosis from local vasoconstriction 2
• Monitor clinically for reaction severity and cardiac effects between doses 2

Important Clinical Pitfalls

Timing is Critical

• Immediate administration upon recognition of anaphylaxis is essential 3, 4
• Delayed epinephrine administration is a major contributor to anaphylaxis fatalities 3, 5
• Epinephrine is most effective when given immediately after symptom onset 3

Dosing Errors to Avoid

• Do not confuse 1:1000 (IM) with 1:10,000 (IV) concentrations - this is a common and potentially fatal error 1
• The 1:1000 solution contains 1 mg/mL and is used for IM/subcutaneous administration 2
• Visual inspection alone is insufficient - check concentration on vial label carefully 1

No Absolute Contraindications

• There are no absolute contraindications to epinephrine in anaphylaxis 1
• The presence of sulfites in the formulation should not deter use 2
• Benefits in life-threatening anaphylaxis outweigh risks even in patients with cardiovascular disease 1, 2

When to Consider Additional Measures

If multiple doses are required or patient remains unstable after 2-3 IM doses, consider:

• Establishing IV access for continuous epinephrine infusion 1
• Transfer to higher level of care with hemodynamic monitoring 1
• IV epinephrine should only be used by experienced clinicians due to risk of fatal arrhythmias 1