What are the effects of administering 1 ml of adrenaline (epinephrine) in asthma patients?

What Happens if 1 mL Adrenaline is Given in Asthma Patients

Administering 1 mL (1 mg) of adrenaline represents a significant overdose in asthma management and creates serious cardiovascular risks that far outweigh any bronchodilator benefit, requiring immediate emergency intervention. 1

Understanding the Dosing Error

The standard subcutaneous dose for acute severe asthma is 0.3-0.5 mL (0.3-0.5 mg) of 1:1000 adrenaline, meaning 1 mL represents a 2-3 fold overdose. 2, 3 This error typically occurs when providers confuse volumes or fail to verify the correct dose before administration. 1

Immediate Clinical Effects

Cardiovascular Complications

• Severe hypertension with rapid blood pressure elevation occurs, potentially causing cerebral hemorrhage, particularly in elderly patients or those with underlying cardiovascular disease. 3

• Cardiac arrhythmias including ventricular ectopy, tachyarrhythmias, and potentially fatal ventricular fibrillation may develop, especially in patients with underlying heart disease or those receiving drugs that sensitize the heart to arrhythmias. 3

• Myocardial ischemia and angina can occur due to increased myocardial oxygen demand combined with the drug's effects, even in patients without known coronary artery disease. 2, 3

• Stress cardiomyopathy has been reported as a complication of excessive epinephrine administration. 3

Systemic Effects

• Anxiety, apprehensiveness, restlessness, tremor, weakness, dizziness, and sweating are common and will be exaggerated with overdose. 3

• Severe palpitations, pallor, nausea, vomiting, and headache typically occur. 3

• Patients may experience disorientation, excitability, impaired memory, panic, and psychomotor agitation. 3

Emergency Management Protocol

Immediate Actions

• Call for emergency assistance immediately and prepare for advanced cardiac life support, as cardiovascular collapse can occur rapidly. 1

• Continuous cardiac monitoring is essential, with electrocardiographic monitoring to detect arrhythmias. 2

• Frequent vital sign assessment every 1-2 minutes initially, monitoring blood pressure, heart rate, and rhythm. 2

Specific Interventions for Overdose Complications

• For severe hypertension: Administer short-acting alpha-blockers such as phentolamine 5-10 mg IV to counteract excessive vasoconstriction. 1

• For hypertensive crisis: Consider nitrates for blood pressure control and coronary vasodilation if no contraindications exist. 1

• For ventricular arrhythmias: Follow advanced cardiac life support protocols with antiarrhythmic agents as indicated. 1

• For tachyarrhythmias: Beta-blockers may be considered cautiously, though they risk worsening bronchospasm in asthma patients—this represents a challenging clinical dilemma requiring specialist consultation. 1

Continued Asthma Management

The adrenaline overdose does not eliminate the underlying bronchospasm, so standard asthma therapy must continue:

• Nebulized selective β2-agonists (salbutamol/albuterol 5 mg) should be administered continuously or every 20 minutes as the primary bronchodilator. 2, 1

• Systemic corticosteroids (prednisolone 30-60 mg orally or IV hydrocortisone 200 mg) must be given early, as their anti-inflammatory effects take 6-12 hours to manifest. 2, 1

• Ipratropium bromide 500 mcg via nebulizer should be added as adjunctive therapy, particularly for severe exacerbations. 2, 1

• Oxygen therapy at 6-8 L/min to maintain SpO2 >90%. 2

• IV magnesium sulfate 2 g over 20 minutes may be considered for severe refractory asthma. 2

Monitoring Duration and Complications

• Extended monitoring for at least 4-6 hours is essential to detect delayed complications, as epinephrine's effects can be prolonged. 1

• Watch for delayed arrhythmias, rebound hypertension, or myocardial ischemia that may manifest hours after the initial overdose. 3

• Patients with underlying cardiovascular disease, hyperthyroidism, diabetes, or those taking medications that interact with epinephrine require even more prolonged observation. 3

Critical Context: Why This Matters

Epinephrine Has No Advantage Over Standard Therapy

• There is no evidence that subcutaneous epinephrine or terbutaline has advantages over inhaled β2-agonists in acute asthma management. 2

• Studies show epinephrine and selective β2-agonists have similar overall efficacy, with a pooled odds ratio for treatment failure of 0.99 (95% CI 0.75 to 1.32). 4

• Research demonstrates that nebulized adrenaline (1-2 mg) produces equivalent bronchodilation to salbutamol without additional benefit. 5, 6

• Even at correct doses (0.3-0.5 mg subcutaneously), epinephrine is only recommended when patients cannot cooperate with inhaled therapy or in severe life-threatening asthma unresponsive to repeated courses of inhaled β2-agonists. 2, 4

The Risk-Benefit Calculation

• The cardiovascular toxicity from overdose far outweighs any bronchodilator benefit, as standard asthma therapy with selective β2-agonists is equally effective without the cardiovascular risks. 1

• In acute severe asthma with baseline PEF around 20-25% predicted, both subcutaneous adrenaline 0.5 mg and terbutaline 0.5 mg produced effective rapid bronchodilation without serious side effects, but this was at appropriate doses. 7

• The nonselective adrenergic properties of epinephrine cause increased heart rate, myocardial irritability, and increased oxygen demand—effects that are magnified with overdose. 2

Prevention of Similar Errors

System-Level Safeguards

• Implement pre-filled syringes with correct doses (0.3 mg or 0.5 mg) to prevent drawing up errors. 1

• Clear labeling distinguishing 1:1000 concentration (for IM/SC use) from 1:10,000 concentration (for IV use) is necessary to prevent confusion. 1

• Double-checking protocols before administering any adrenaline dose should be mandatory, with independent verification by a second provider when possible. 1

Clinical Decision-Making

• First-line treatment for all acute asthma exacerbations should be inhaled selective β2-agonists and systemic corticosteroids. 4

• Reserve epinephrine for patients with concomitant anaphylaxis or angioedema, or severe/life-threatening asthma unresponsive to repeated courses of inhaled β2-agonists. 4

• Never use IV epinephrine in asthma except during cardiac arrest or in profoundly hypotensive patients who have failed to respond to IV volume replacement and several injected doses of epinephrine, as it carries a 4% incidence of serious side effects. 2