Severe Toxicity and Potential Fatality from 2 mL Adrenaline Bolus in Asthma
Administering 2 mL (2 mg) of adrenaline at once to an asthma patient represents a massive overdose that can cause life-threatening cardiovascular complications including severe hypertension, cerebral hemorrhage, ventricular arrhythmias, myocardial ischemia, and potentially death. 1
Standard Dosing vs. Overdose Context
The recommended dose for acute severe asthma is 0.3-0.5 mg (0.3-0.5 mL) subcutaneously, repeated every 5-15 minutes if needed 2, 3, 1. A 2 mL dose represents 4-7 times the maximum recommended single dose, creating extreme risk of toxicity 1.
Expected Cardiovascular Complications
Immediate Life-Threatening Effects
- Severe hypertension with rapid blood pressure elevation that can produce cerebral hemorrhage, particularly dangerous in any patient with underlying vascular disease 1
- Ventricular arrhythmias including potentially fatal ventricular fibrillation, especially in patients with underlying heart disease or those receiving drugs that sensitize the heart 1
- Acute coronary syndrome with angina or myocardial infarction from increased myocardial oxygen demand and coronary vasoconstriction 1
- Stress cardiomyopathy (Takotsubo syndrome) from catecholamine excess 1
Additional Severe Adverse Effects
- Severe tachycardia and palpitations with heart rates potentially exceeding 150-180 bpm 1
- Pulmonary edema from acute left ventricular dysfunction 1
- Extreme anxiety, agitation, and panic from massive sympathetic stimulation 1
- Severe tremor, headache, and potential seizures 1
Clinical Management of Overdose
Immediate Actions
- Call for emergency assistance immediately and prepare for advanced cardiac life support 4
- Continuous cardiac monitoring with 12-lead ECG to detect arrhythmias and ischemia 1
- Frequent blood pressure monitoring (every 2-5 minutes initially) to detect hypertensive crisis 1
Specific Interventions Based on Complications
For severe hypertension:
- Administer short-acting alpha-blockers (phentolamine 5-10 mg IV) to counteract excessive vasoconstriction 1
- Consider nitrates for blood pressure control and coronary vasodilation if no contraindications exist 5
For ventricular arrhythmias:
- Follow advanced cardiac life support protocols with antiarrhythmic agents as indicated 4
- Beta-blockers may be considered cautiously for tachyarrhythmias, though they can worsen bronchospasm in asthma patients 5, 1
For ongoing bronchospasm:
- Continue nebulized selective β2-agonists (salbutamol/albuterol) as the adrenaline overdose does not eliminate need for bronchodilation 2, 3
- Administer systemic corticosteroids (prednisolone 30-60 mg orally or IV hydrocortisone 200 mg) 3
- Consider ipratropium bromide as adjunctive therapy 3
Important Clinical Caveats
Duration of Toxicity
The effects of subcutaneous adrenaline typically peak at 5-15 minutes but can persist for 30-60 minutes or longer with massive overdose 6. Extended monitoring for at least 4-6 hours is essential to detect delayed complications 4.
Asthma-Specific Considerations
While adrenaline has both beta-2 (bronchodilator) and alpha (vasoconstrictor) effects, the cardiovascular toxicity from overdose far outweighs any bronchodilator benefit 2. Standard asthma therapy with selective β2-agonists is equally effective without the cardiovascular risks 4, 2.
Risk Factors for Worse Outcomes
Patients at highest risk for severe complications include those with:
- Pre-existing cardiovascular disease (coronary artery disease, hypertension, arrhythmias) 1
- Hyperthyroidism (increased sensitivity to catecholamines) 1
- Elderly age (increased risk of cerebral hemorrhage and cardiac complications) 1
- Concurrent medications including tricyclic antidepressants, MAO inhibitors, or cardiac glycosides that potentiate adrenaline effects 1
Prevention of Similar Errors
This represents a critical medication error. Standard adrenaline concentration for anaphylaxis/asthma is 1:1000 (1 mg/mL), and the maximum single dose is 0.5 mL 1. Systems should implement: