Is it appropriate to administer intramuscular (IM) adrenaline (epinephrine) 0.5 ml to a hemodynamically stable adult patient without a clear indication, such as anaphylaxis or cardiac arrest?

IM Adrenaline 0.5 mL Should NOT Be Given to Hemodynamically Stable Patients Without Clear Indication

Administering intramuscular adrenaline to a hemodynamically stable patient is only appropriate when there is a clear diagnosis of anaphylaxis or another specific indication—hemodynamic stability alone does not justify its use, and giving it without proper indication exposes the patient to unnecessary cardiac risks. 1, 2

When IM Adrenaline IS Indicated

Adrenaline is indicated specifically for:

• Anaphylaxis diagnosis confirmed by:

  • Acute onset with skin/mucosal involvement PLUS respiratory compromise or hypotension/syncope 3
  • Two or more organ systems involved after allergen exposure (skin, respiratory, cardiovascular, gastrointestinal) 3
  • Isolated hypotension after known allergen exposure (even without skin signs, which are absent in 10% of cases) 3

• Specific anaphylaxis triggers requiring immediate treatment:

  • Respiratory symptoms: difficulty breathing, wheezing, throat tightness, stridor 4
  • Cardiovascular symptoms: hypotension, dizziness, syncope, loss of consciousness 4
  • Widespread urticaria with systemic symptoms after known allergen exposure 4
  • Known allergen exposure in someone with previous anaphylaxis, even if symptoms are initially mild 4

1, 3, 4, 2

Why NOT to Give Adrenaline to Stable Patients Without Indication

Adrenaline carries significant cardiac risks when used inappropriately:

• May produce ventricular arrhythmias, particularly in patients with underlying heart disease 2
• Can aggravate angina pectoris 2
• Increases myocardial oxygen demand, creating potential ischemia 1
• Adverse effects include anxiety, tremor, palpitations, and potentially fatal ventricular fibrillation 2
• Patients with hyperthyroidism, Parkinson's disease, diabetes, and pheochromocytoma are at greater risk of adverse reactions 2

1, 2, 5

Critical Distinction: Hemodynamically Stable WITH Anaphylaxis vs. Stable WITHOUT Anaphylaxis

If the patient is hemodynamically stable BUT has confirmed anaphylaxis, adrenaline SHOULD be given:

• Early adrenaline use in hemodynamically stable anaphylaxis patients reduces the risk of developing subsequent hypotension (OR 0.254,95% CI 0.091-0.706) 6
• Approximately 12% (40/340) of initially normotensive anaphylaxis patients develop hypotension during their ED stay 6
• Delayed epinephrine administration is associated with increased mortality and biphasic reactions 1, 4
• When in doubt about anaphylaxis diagnosis, err on the side of administering epinephrine—the risk of untreated anaphylaxis exceeds the risk of appropriate epinephrine use 4

1, 3, 4, 6

If the patient is hemodynamically stable WITHOUT anaphylaxis, adrenaline should NOT be given:

• No indication exists for prophylactic or empiric adrenaline in stable patients 1, 2
• Iatrogenic overdose from confusion about dosing has caused life-threatening cardiac complications 5
• The risk-benefit ratio does not favor administration without clear indication 2

2, 5

Correct Dosing IF Anaphylaxis Is Confirmed

For adults ≥30 kg with anaphylaxis:

• 0.3-0.5 mg (0.3-0.5 mL of 1:1000 solution) IM into anterolateral thigh 1, 2
• Maximum single dose: 0.5 mg 1, 3
• Repeat every 5-10 minutes as needed if symptoms persist or worsen 1, 2
• 10-20% of patients require more than one dose 1, 3

1, 3, 2

Common Pitfalls to Avoid

• Do not confuse vasovagal reactions with anaphylaxis: Vasovagal events show pallor, weakness, nausea, diaphoresis, bradycardia, and hypotension WITHOUT skin manifestations (urticaria, angioedema, flush, pruritus) that are present in most anaphylaxis cases 1
• Do not use wrong concentration: 1:1000 (1 mg/mL) for IM use; 1:10,000 (0.1 mg/mL) for IV use only—confusion has caused fatal overdoses 7, 5
• Do not inject into wrong site: Use anterolateral thigh (vastus lateralis), NOT deltoid, buttocks, digits, hands, or feet 4, 2
• Do not substitute antihistamines or bronchodilators: These are adjunctive only and do not treat life-threatening manifestations 1, 4

1, 4, 7, 2, 5

Bottom Line Algorithm

1. Is there confirmed anaphylaxis? (acute onset with multi-system involvement or known allergen exposure with appropriate symptoms) 3

   • YES → Give IM adrenaline 0.3-0.5 mg immediately, regardless of hemodynamic status 1, 3, 4, 6
   • NO → Do NOT give adrenaline 2

2. If anaphylaxis confirmed, monitor and repeat dosing every 5-10 minutes if symptoms persist or progress 1, 2

3. If patient fails to respond to multiple IM doses, escalate to IV epinephrine infusion (1:10,000 solution at 1-4 mcg/min) 3

1, 3, 4, 2, 6