Aminophylline

Pronunciation: am-in-OFF-i-lin.

Generic name
aminophylline (theophylline-ethylenediamine)
Drug class
Methylxanthine bronchodilator
Form
Solution for injection/infusion, typically 25 mg/mL (250 mg/10 mL ampoule)
Route
Intravenous injection or infusion (administered by a healthcare professional in a hospital/clinical setting)
Legal status
Prescription-only medicine in every market reviewed

Availability and supply rules vary by country

Trade names by country: United States · United Kingdom · Canada · Australia · New Zealand

Australia: DBL Aminophylline 250 mg/10 mL injection ampoule (5) · Full directory

What aminophylline (theophylline-ethylenediamine) is and how it works

Aminophylline is an intravenous bronchodilator -- a 2:1 complex of theophylline and ethylenediamine -- used in hospital to help relax the muscles around narrowed airways during severe asthma or COPD flare-ups, alongside inhaled bronchodilators and steroids. It is given and dosed only by healthcare professionals because it has a narrow therapeutic index: the dose that helps and the dose that can cause serious harm are relatively close together. (1) (2)

If you are given aminophylline, it is almost always because you have a severe asthma or COPD flare-up needing hospital-level treatment. Your care team will usually check the level of the related substance (theophylline) in your blood regularly during treatment, because getting the dose right -- and adjusting it based on your blood level, other medicines you take, your age, and conditions like liver or heart disease -- is essential to avoid side effects that can become serious, including seizures and abnormal heart rhythms.

Mechanism of action: how aminophylline (theophylline-ethylenediamine) works

Aminophylline is a 2:1 complex of theophylline and ethylenediamine (the ethylenediamine component improves water solubility for IV use). Theophylline, a methylxanthine, causes bronchodilation via phosphodiesterase inhibition and adenosine receptor antagonism, relaxing bronchial and pulmonary vascular smooth muscle and increasing diaphragmatic contractility. (1) (2)

What aminophylline (theophylline-ethylenediamine) is used for

Acute severe asthma and COPD exacerbations

Aminophylline is used as an add-on treatment alongside inhaled beta-agonist bronchodilators and corticosteroids for acute exacerbations of reversible airway obstruction, including severe asthma attacks (status asthmaticus) and flare-ups of chronic obstructive pulmonary disease (COPD), chronic bronchitis, and emphysema. (1) (2) (5) (6)

Pulmonary oedema and left ventricular heart failure (UK-specific use)

In the UK, aminophylline injection is also indicated for pulmonary oedema and left ventricular heart failure, in addition to its bronchodilator uses. (2)

Before taking aminophylline (theophylline-ethylenediamine)

Do not take / not appropriate for

  • Do not receive aminophylline if you have had an allergic (hypersensitivity) reaction to theophylline, aminophylline, or ethylenediamine. (all countries) (1) (2)
  • Aminophylline should not be given together with other xanthine-type medicines (e.g. oral theophylline). (United Kingdom) (2)
  • Aminophylline should not be given to people with acute porphyria. (United Kingdom) (2)
  • Use in children under 6 months of age is not recommended because of reduced ability to eliminate theophylline. (all countries) (1) (2)

Tell your clinician about

  • Whether you are already taking oral theophylline or any other xanthine-containing medicine.
  • Any history of seizures, heart disease, liver disease, kidney disease, or high blood pressure.
  • Whether you smoke or have recently stopped smoking (smoking changes how quickly your body clears theophylline).
  • Whether you have a fever, a current infection, or have recently been unwell.
  • All other medicines you take, including antibiotics (such as erythromycin or ciprofloxacin), cimetidine, anti-seizure medicines (phenytoin, carbamazepine), rifampicin, oral contraceptives, or St John's Wort.
  • Whether you are or could be pregnant, or are breastfeeding.
  • Your age, especially if you are over 55-60 years old.
(1) (2)

How to take aminophylline (theophylline-ethylenediamine)

  • Aminophylline is given only by a healthcare professional, by slow intravenous injection or as an intravenous infusion, in a hospital or closely monitored clinical setting.
  • It is never a medicine you take home and self-administer, and the dose is individualised and adjusted based on your blood (serum) theophylline level, not a single fixed dose for everyone.
  • Do not attempt to adjust the rate or amount of any infusion yourself -- this is managed entirely by your care team.
(1) (2)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4) (5) (6)

Missed dose

Not applicable in the usual sense -- aminophylline is given by a healthcare professional in a monitored clinical setting, and any dosing schedule or timing is managed entirely by your care team, not by you.

Overdose

Because aminophylline is only given under direct medical supervision, an overdose is managed by the treating clinical team, not the patient. If you notice persistent vomiting, a fast or irregular heartbeat, tremor, agitation, or any seizure-like activity during or after treatment, tell staff or seek emergency help immediately -- these can be early or serious signs of theophylline toxicity, which can occur at levels not far above the therapeutic range. (1) (2)

Side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms.

Nausea, vomiting, headache, restlessness, tremor, and difficulty sleeping (insomnia), most often at the higher end of or above the therapeutic serum range.

What to notice: Nausea, vomiting, headache, restlessness, tremor, and difficulty sleeping (insomnia), most often at the higher end of or above the therapeutic serum range.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1) (2)

Fast heartbeat (tachycardia) and palpitations.

What to notice: Fast heartbeat (tachycardia) and palpitations.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (2)

Diarrhoea and transient increase in urination.

What to notice: Diarrhoea and transient increase in urination.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Serious warnings

Theophylline toxicity -- narrow therapeutic index — high caution

Symptoms: Persistent vomiting, marked restlessness or agitation, tremor, fast or irregular heartbeat.

Action: Aminophylline has a narrow therapeutic index -- the effective dose and a harmful dose are relatively close together (therapeutic range approximately 10-20 mcg/mL; adverse effects become more frequent and severe above 20 mcg/mL). Your care team will monitor your blood theophylline level regularly, especially at the start of treatment and at roughly 24-hour intervals during ongoing infusion, and adjust your dose accordingly. Tell staff immediately about any of these symptoms. (1) (2)

Seizures at toxic theophylline levels — emergency

Symptoms: Convulsions/seizure activity, which can occur even without earlier warning symptoms of toxicity.

Action: Severe, potentially life-threatening seizures can occur, particularly at serum levels above about 30 mcg/mL, and risk is higher in elderly patients and those with a seizure or neurological disorder history. This requires emergency treatment (e.g. intravenous benzodiazepines) and is a key reason serum-level monitoring is a real safety requirement, not an optional precaution. (1) (2)

Cardiac arrhythmias at toxic theophylline levels — emergency

Symptoms: Irregular, rapid, or pounding heartbeat; dizziness; fainting.

Action: Serious, potentially life-threatening cardiac arrhythmias (including ventricular arrhythmias) can occur at toxic theophylline concentrations, especially with rapid IV administration or in people with underlying heart disease. Aminophylline must be given slowly (no faster than 25 mg/minute) and only with cardiac and clinical monitoring in place. Seek immediate medical attention for any irregular or racing heartbeat. (1) (2)

Low blood potassium (hypokalaemia) — high caution

Symptoms: Muscle weakness, cramps, abnormal heart rhythm.

Action: Aminophylline, especially combined with beta-agonist bronchodilators, corticosteroids, or diuretics, can lower blood potassium. Your care team will monitor your potassium level, particularly during the early phase of treatment. (2)

Severe allergic reaction — emergency

Symptoms: Rash, widespread skin peeling (exfoliative dermatitis), swelling of the face/lips/throat, difficulty breathing.

Action: Rare but serious hypersensitivity reactions have been reported, particularly in people previously sensitised to ethylenediamine. Seek emergency help immediately for any of these symptoms. (1)

Interactions

  • Medicines that can raise theophylline blood levels (increasing toxicity risk): cimetidine, erythromycin, ciprofloxacin and other macrolide/quinolone antibiotics, fluvoxamine, calcium channel blockers, and oral contraceptives. (1) (2)
  • Medicines that can lower theophylline blood levels (reducing effectiveness): rifampicin, phenytoin, carbamazepine, and other antiepileptic medicines, and St John's Wort. (1) (2)
  • Concurrent sympathomimetic medicines or beta2-agonist bronchodilators can increase the risk of cardiac arrhythmia when combined with aminophylline. (2)
  • Smoking increases the rate at which the body clears theophylline, so smokers may need higher doses; recently stopping smoking can raise theophylline levels and increase toxicity risk if the dose is not adjusted. (1)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

Theophylline crosses the placenta. Aminophylline should be used in pregnancy only if the expected benefit is considered to outweigh any risk, and only under specialist medical supervision. (1) (2) (3) (4) (5) (6)

Breastfeeding

Theophylline passes into breast milk and can affect a nursing infant; breastfeeding is generally advised against during aminophylline treatment unless a clinician judges otherwise. (1) (2) (3) (4) (5) (6)

Children

Not recommended for children under 6 months of age due to reduced ability to clear theophylline; when used in older children, dosing is individualised and closely monitored by a paediatric specialist. (1) (2) (3) (4) (5) (6)

Elderly

Patients over 55-60 years generally require lower maintenance doses because theophylline clearance is reduced with age, and are more sensitive to toxic effects, including after long-term overdosage -- closer monitoring is required in this group. (1) (2) (3) (4) (5) (6)

Hepatic_impairment

Liver disease reduces theophylline clearance and increases the risk of toxicity; dose reduction and closer serum-level monitoring are required. (1) (2) (3) (4) (5) (6)

Renal_impairment

Not specifically established as requiring its own dose adjustment in the sources reviewed for this dossier, though general caution applies given the narrow therapeutic index. (1) (2) (3) (4) (5) (6)

Source_ids

US-DAILYMED-AMINOPHYLLINE-INJ-2026,UK-EMC-AMINOPHYLLINE-2026 (1) (2) (3) (4) (5) (6)

Monitoring

Before starting

  • Baseline assessment of cardiac, hepatic, and renal function
  • Review of all current medicines for interacting drugs
  • Smoking status

During treatment

  • Serum theophylline level checked approximately 30 minutes after the loading dose, again after one expected drug half-life, and at roughly 24-hour intervals during ongoing infusion.
  • Serum theophylline level checked whenever signs of toxicity appear, or when a new illness, fever, or interacting medicine is started or stopped.
  • Heart rhythm/cardiac monitoring during administration, especially in patients with underlying heart disease.
  • Serum potassium monitoring, particularly early in treatment and with concurrent beta-agonists, corticosteroids, or diuretics.
(1) (2)

Storage

Aminophylline injection is stored and handled by healthcare professionals according to the product's labelling -- commonly stored below 25 degrees C and protected from light.

Study the drug class: Methylxanthines

Professional information

Clinician-facing context only, sourced from the current US FDA DailyMed aminophylline injection label and the UK emc aminophylline SmPC; verify against the current full label in the relevant jurisdiction before prescribing.

United States

Indication: Adjunct treatment of acute exacerbations of reversible airflow obstruction (asthma, COPD)

Dose summary: Loading dose 4.6 mg/kg theophylline (5.7 mg/kg aminophylline) IV over 30 min; maintenance 0.2-0.8 mg/kg/hr theophylline depending on population; target serum concentration 10-15 mcg/mL; individualise by serum level.

Renal context: Not specifically established in the source reviewed for this dossier. (1)

United Kingdom

Indication: Reversible airways obstruction (status asthmaticus, acute severe bronchospasm), pulmonary oedema, left ventricular heart failure

Dose summary: IV rate must not exceed 25 mg aminophylline/minute; maintenance ~1 mg/kg/hr (children 6mo-9yr), ~0.5 mg/kg/hr (healthy adults), ~0.3 mg/kg/hr (elderly); therapeutic range 10-20 micrograms/mL.

Renal context: Not specifically established in the source reviewed for this dossier. (2)

Mechanism of action

Hepatic guidance

Hepatic impairment reduces theophylline clearance; dose reduction and increased monitoring frequency are required.

Overdose note

Acute overdose (serum >100 mcg/mL) or chronic overdosage (>30 mcg/mL in patients >=60 years) carries high risk of life-threatening seizures/arrhythmias; management includes stopping the infusion, activated charcoal, IV benzodiazepines for seizures, and consideration of charcoal hemoperfusion or hemodialysis for severe cases. (1) (2)

Frequently asked questions

Why does aminophylline need such careful blood monitoring?

Aminophylline has a narrow therapeutic index, meaning the dose that helps and a dose that can cause serious harm (seizures, dangerous heart rhythms) are relatively close together. Your care team checks your blood theophylline level regularly -- for example after the loading dose, after about one drug half-life, and roughly every 24 hours during ongoing treatment -- to keep your dose in the safe, effective range. (1) (2)

Can aminophylline cause seizures?

Yes, at toxic serum theophylline levels (typically above about 30 mcg/mL), severe and potentially life-threatening seizures can occur, sometimes without earlier warning symptoms. This is a key reason serum-level monitoring during treatment is essential, not optional. (1)

Does smoking affect aminophylline dosing?

Yes. Smoking speeds up how quickly the body clears theophylline, so smokers often need higher maintenance doses. If you stop smoking during treatment, your theophylline level can rise and increase toxicity risk unless your dose is adjusted -- always tell your care team about any change in smoking status. (1)

Is aminophylline available as a tablet I can take at home?

The intravenous form covered here is given only in hospital under medical supervision. Some markets have historically had oral aminophylline tablets, but availability varies -- for example, several older oral aminophylline products in Canada are no longer marketed. Ask your prescriber what is currently available and appropriate for you. (4)

What is the mechanism of action of aminophylline (theophylline-ethylenediamine)?

Aminophylline is a 2:1 complex of theophylline and ethylenediamine (the ethylenediamine component improves water solubility for IV use). Theophylline, a methylxanthine, causes bronchodilation via phosphodiesterase inhibition and adenosine receptor antagonism, relaxing bronchial and pulmonary vascular smooth muscle and increasing diaphragmatic contractility. (1) (2)

What is the generic name of Aminophylline?

The generic name is aminophylline (theophylline-ethylenediamine). (1) (2)

What class of drug is aminophylline (theophylline-ethylenediamine)?

Aminophylline is classed as: Methylxanthine bronchodilator. (1) (2)

References

  1. AMINOPHYLLINE injection, solution -- prescribing informationU.S. Food and Drug Administration / DailyMed (NIH) · United States · accessed 2026-07-31 · source 1
  2. Aminophylline 25 mg/ml Solution for Injection/Infusion -- Summary of Product Characteristicselectronic medicines compendium (emc), United Kingdom · United Kingdom · accessed 2026-07-31 · source 2
  3. Aminophyllin 125 mg -- FachinformationGerman national medicines information (Fachinformation), representative EU/EEA national authorisation · European Union (Germany, national authorisation) · accessed 2026-07-31 · source 3
  4. AMINOPHYLLINE INJ 25MG/ML (DIN 00582662, Omega Laboratories Limited) and related aminophylline DINsHealth Canada Drug Product Database (live API query) · Canada · accessed 2026-07-31 · source 4
  5. DBL Aminophylline 250mg/10mL injection ampoule -- ARTG entry 16355Therapeutic Goods Administration (TGA), Australia -- Australian Register of Therapeutic Goods (ARTG) · Australia · accessed 2026-07-31 · source 5
  6. DBL Aminophylline Injection 250 mg in 10 mL -- New Zealand Data Sheet (version pfdamini11123)Medsafe (New Zealand Medicines and Medical Devices Safety Authority) · New Zealand · accessed 2026-07-31 · source 6

Brand names by country

Single-ingredient aminophylline (theophylline-ethylenediamine) names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

  • Aminophylline injection, USP (generic) (1)FDA approved prescription injectable · 25 mg/mL · multiple manufacturers

United Kingdom

  • Aminophylline 25 mg/mL solution for injection/infusion (hameln pharma / ADVANZ Pharma, generic) (2)MHRA licensed emc smpc confirmed prescription injectable · 25 mg/mL · hameln pharma ltd; ADVANZ Pharma

Canada

  • AMINOPHYLLINE INJ

Australia

  • DBL Aminophylline 250 mg/10 mL injection ampoule (5)TGA ARTG 16355 registered confirmed prescription injectable Schedule 4 · 25 mg/mL (250 mg/10 mL) · Pfizer Australia Pty Ltd

New Zealand

  • DBL Aminophylline Injection 250 mg in 10 mL (6)Medsafe approved confirmed prescription injectable · 25 mg/mL (250 mg/10 mL) · Pfizer New Zealand (DBL brand)
View brands in additional countries.

European Union

Aminophyllin 125 mg (Germany, national authorisation; brand historically also marketed as Euphyllin) (3)

This page provides general reference information about aminophylline, an intravenous medicine given only under medical supervision, and is not a substitute for advice from your clinician. All dosing, monitoring, and treatment decisions are made by your healthcare team.

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