Aminophylline
Methylxanthines
Methylxanthines
Theophylline combined with ethylenediamine so it dissolves for intravenous use; same narrow range and interactions as theophylline.
Quick facts
- Group
- Methylxanthines
- Target
- Adenosine A2A receptor (and phosphodiesterases PDE3, PDE4)
- Used for
- Acute exacerbations of COPD
- Key effects
- Nausea · Headache and insomnia · Nervousness
- Monitor
- Continuous ECG and heart rate · Potassium and glucose
- ATC
- R03DA05
No doses: the clinician sets them by the current guideline.
Mechanism of action
The figure shows theophylline, the active part of aminophylline, bound to the human adenosine A2A receptor.
Aminophylline is a complex of theophylline with ethylenediamine, which makes it soluble in water. Once in the body it releases theophylline, which inhibits phosphodiesterases and blocks adenosine receptors to relax the airways and stimulate breathing. It is used intravenously in severe asthma or COPD exacerbations that do not respond to standard treatment, and carries all the toxicity and interaction risks of theophylline. Ethylenediamine can cause allergic reactions of its own.
- Aminophylline is given intravenously and releases theophylline
- Theophylline inhibits phosphodiesterases and blocks adenosine
- Airways relax and breathing is stimulated
- Levels are checked because toxicity is close
Indications
- Severe acute asthma not responding to inhaled bronchodilators and systemic corticosteroids (add-on) Asthma →
- Acute exacerbations of COPD in selected cases Chronic obstructive pulmonary disease (COPD) →
Adverse effects
Common
- Nausea, vomiting and stomach upset
- Headache and insomnia
- Nervousness, irritability and tremor
- Palpitations and fast heartbeat
- Increased urination
Contraindications
- Hypersensitivity to theophylline or to ethylenediamine
- Extreme caution in active peptic ulcer, seizure disorders and tachyarrhythmias
- Caution where clearance is reduced: heart failure, liver disease, old age, fever with viral illness, hypothyroidism
Key interactions
- CYP1A2 inhibitors: ciprofloxacin, erythromycin, clarithromycin, cimetidine, fluvoxamine
- Slow theophylline clearance and raise levels into the toxic range
- Smoking, rifampicin, carbamazepine, phenobarbital, phenytoin, St John's wort
- Speed clearance and lower levels; levels rise when they are stopped (including quitting smoking)
- Lithium
- Theophylline increases lithium clearance and can lower its effect
- Halothane and other agents that sensitise the heart to catecholamines; ketamine
- Higher risk of ventricular arrhythmias; ketamine may lower the seizure threshold
What is monitored
- Serum theophylline levels during the infusion
- Continuous ECG and heart rate
- Potassium and glucose
- Seizure watch
Administration and safety
- Intravenous: a slow loading injection or infusion, never a rapid push, using an infusion pump
- Ask whether the patient already takes oral theophylline before any loading dose
- Check compatibility before mixing with other drugs in the same line
- Unused portions of the vial are discarded
Pregnancy and breastfeeding
As with theophylline, it crosses the placenta and needs close level monitoring late in pregnancy.
Nursing care
- Confirm prior theophylline use and get a baseline level if so
- Keep the patient on a monitor; report tachycardia, arrhythmia or vomiting
- Keep seizure precautions
Pharmacokinetics
- Distribution
- Theophylline distributes in body water
- Metabolism
- As theophylline: liver CYP1A2, saturable
- Half-life
- As theophylline, highly variable between patients
- Onset and duration
- Rapid intravenous effect
Test yourself
Think of the answer, then tap the question to see it.
What is aminophylline made of?
Theophylline complexed with ethylenediamine, which makes it water-soluble for intravenous use.
What must be asked before giving a loading dose of aminophylline?
Whether the patient already takes theophylline, to avoid toxic levels.
Why is aminophylline never given as a rapid intravenous push?
Rapid injection can cause arrhythmias, low blood pressure and seizures.
Connections
← Back to the class: Methylxanthines
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - AMINOPHYLLINE injection, solution (DailyMed (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.