[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Methylxanthines](https://durgical.com/en/pharmacology/classes/methylxanthines/) › Aminophylline

# Aminophylline

## Methylxanthines?

Methylxanthines

Theophylline combined with ethylenediamine so it dissolves for intravenous use; same narrow range and interactions as theophylline.

Updated Nov 1, 2026

## Quick facts

**Group**
[Methylxanthines](https://durgical.com/en/pharmacology/classes/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.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

◎**Adenosine A2A receptor (and phosphodiesterases PDE3, PDE4)**Aminophylline

ⓘ The figure shows theophylline, the active part of aminophylline, bound to the human adenosine A2A receptor.

**Target in 3D:** Adenosine A2A receptor (and phosphodiesterases PDE3, PDE4). PDB structure 5MZJ (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/5MZJ) · Drag to rotate · pinch to zoom

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 →](https://durgical.com/en/conditions/asthma/)
- Acute exacerbations of COPD in selected cases [Chronic obstructive pulmonary disease (COPD) →](https://durgical.com/en/conditions/chronic-obstructive-pulmonary-disease/)

## Adverse effects

### Common

- Nausea, vomiting and stomach upset
- Headache and insomnia
- Nervousness, irritability and tremor
- Palpitations and fast heartbeat
- Increased urination

### Serious (rare, important)

- Toxicity: persistent vomiting, tachyarrhythmias, seizures that are hard to control
- Hypokalaemia, hyperglycaemia and acid–base disturbance in overdose
- Seizures or arrhythmia can be the first sign, without earlier nausea
- Arrhythmia and low blood pressure with rapid intravenous injection

## 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

## Memory aid

AMINOphylline = A Mix: theophylline + ethylenediamine, In a vein, Never fast.

## 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.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/aminophylline/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## Connections

## Related drugs 2

- [Theophylline](https://durgical.com/en/pharmacology/theophylline/)
- [Caffeine citrate](https://durgical.com/en/pharmacology/caffeine-citrate/)

## Related conditions 2

- [Asthma](https://durgical.com/en/conditions/asthma/)
- [Chronic obstructive pulmonary disease (COPD)](https://durgical.com/en/conditions/chronic-obstructive-pulmonary-disease/)

[← Back to the class: Methylxanthines](https://durgical.com/en/pharmacology/classes/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](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=9a663ef3-881f-48bd-2689-3713b24545c2) (DailyMed (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=R03DA05) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/aminophylline/