Can adrenaline (epinephrine) be administered via injection?

Administration of Adrenaline (Epinephrine) by Injection

Yes, adrenaline (epinephrine) can be administered via injection, with intramuscular injection being the preferred route for anaphylaxis due to its favorable safety profile and effectiveness.

Routes of Administration for Adrenaline

Intramuscular (IM) Route - First Line for Anaphylaxis

• Preferred injection site: Anterolateral aspect of the mid-thigh 1, 2
• Adult dosing: 0.3-0.5 mg (0.3-0.5 mL of 1:1000 solution) 1, 2
• Pediatric dosing: 0.01 mg/kg (0.01 mL/kg) up to maximum 0.3 mg for children <30 kg 2
• Frequency: Can be repeated every 5-15 minutes as needed based on clinical response 1, 2
• Administration technique: Can be given through clothing if necessary 2
• Advantages:
  • Rapid absorption
  • Higher and more rapid peak plasma levels compared to subcutaneous route 1
  • Safer profile compared to IV administration 3, 4

Subcutaneous (SC) Route

• Can be used but has slower absorption compared to IM route 1
• Same dosing as IM route 2
• Not preferred due to delayed onset of action in anaphylaxis 5

Intravenous (IV) Route - Reserved for Specific Situations

• Only indicated for:
  • Cardiac arrest
  • Profound hypotension not responding to IM epinephrine and fluid resuscitation 1
• IV bolus dosing: 0.05-0.1 mg (5-10% of cardiac arrest dose) 1
• IV infusion preparation:
  • Option 1: 1 mg in 250 mL D5W (4.0 μg/mL) at 1-4 μg/min, up to 10 μg/min 1
  • Option 2: 1 mg in 100 mL saline (10 μg/mL) at 5-15 μg/min 1
• Caution: Requires continuous hemodynamic monitoring due to risk of potentially lethal arrhythmias 1, 3

Important Clinical Considerations

Safety Profile

• Side effects occur in approximately 21.6% of cases but are usually mild and transient 4
• Common side effects: tremors, palpitations, and anxiety 4
• Severe adverse effects (high blood pressure, chest discomfort, ECG alterations) occur in only about 3% of cases 4
• Risk factors for side effects:
  • Older age
  • Higher dose
  • Intravenous route of administration 4

Critical Pitfalls to Avoid

1. Dosing errors: Confusion between anaphylaxis dosing (lower) and cardiac arrest dosing (higher) has led to iatrogenic overdose 3
2. Improper route selection: IV administration when IM would be safer 3, 4
3. Delayed administration: Failure to inject epinephrine promptly contributes to anaphylaxis fatalities 5
4. Repeated injections at same site: Can cause tissue necrosis due to vasoconstriction 2

Best Practices

• For children, hold the leg firmly and limit movement during injection 2
• Use a needle long enough (at least 1/2 to 5/8 inch) for IM administration 2
• Inspect solution for particulate matter or discoloration before administration 2
• Monitor the patient clinically for severity of allergic reaction and cardiac effects 2
• Place patient in recumbent position with elevated lower extremities after administration 1

In emergency situations such as anaphylaxis, restricting adrenaline administration due to fear of potential adverse effects is not justified given its life-saving benefits 4. The benefits of prompt administration in anaphylaxis far outweigh the risks of typically mild and transient side effects.