Aminophylline Infusion Protocol for Severe Asthma

Primary Recommendations

The British Thoracic Society recommends administering intravenous aminophylline with a loading dose of 5 mg/kg over 20 minutes, followed by a maintenance infusion of 0.5 mg/kg/hour in adults, but omit the loading dose entirely if the patient has taken any theophylline within the previous 24 hours 1, 2, 3, 4

Aminophylline should only be considered when patients exhibit life-threatening characteristics, such as peak expiratory flow (PEF) <33% of predicted, silent chest, cyanosis, or feeble respiratory effort, despite initial treatment with oxygen, systemic corticosteroids, and nebulized beta-agonists 1, 2, 3
The American Thoracic Society notes that aminophylline is indicated for life-threatening asthma features, including bradycardia or hypotension, exhaustion, confusion, or coma, and severe hypoxia (PaO2 <8 kPa) despite oxygen therapy 2

The maintenance infusion rate for adults is 0.5-0.7 mg/kg/hour, with a target serum level of 10-15 mcg/mL 6, 3, 4
For children, the maintenance infusion rate is 1 mg/kg/hour 5

Measure serum theophylline concentration 30 minutes after loading dose completion to guide further dosing, and monitor continuously for signs of toxicity: palpitations, arrhythmias, nausea, vomiting, tremor 4
Continue measuring PEF before and after bronchodilators at least every 4 hours, and maintain continuous oximetry with target SaO2 >92% 1, 2

The British Thoracic Society guidelines recommend high-flow oxygen via face mask, nebulized beta-agonist, and systemic corticosteroids as initial treatment for all patients, with aminophylline considered only for life-threatening features that persist despite initial therapy 1, 2, 3, 4

The evidence for aminophylline in acute asthma is mixed, with a 2012 Cochrane meta-analysis finding no significant benefit in hospital admissions, PEF improvement, or airflow outcomes when aminophylline was added to inhaled beta-agonists, but older guidelines recommend aminophylline for life-threatening asthma 1, 2, 3, 4
For COPD, the evidence is clearer, with current guidelines not recommending aminophylline for COPD exacerbations 8, 7

Reduce aminophylline dose in patients taking drugs that decrease theophylline clearance, such as cimetidine, macrolide antibiotics, fluoroquinolones, and oral contraceptives 7