Xanthine bronchodilator (theophylline ethylenediamine) Pregnancy: It is not known whether theophyllines cause foetal harm; safe use in pregnancy has not been established but theophyllines have been used in pregnancy without teratogenicity or other adverse foetal effect. Theophylline crosses the placenta. Use only if considered essential by the physician. Breast-feeding: theophylline is distributed into milk and may induce irritability or other signs of toxicity in nursing infants — should not be used if the mother is breast-feeding.

Aminophylline IV

Brand names: Aminophylline Injection

Aminophylline IV is an intravenous methylxanthine (a theophylline-ethylenediamine complex) used in the emergency setting as an adjunct in acute severe asthma or COPD unresponsive to standard bronchodilator therapy.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Patients NOT currently receiving theophylline preparations: loading dose up to 250-500 mg (5 mg/kg) by slow intravenous administration at a rate not exceeding 25 mg aminophylline per minute. Maintenance (otherwise healthy non-smoking adults): 0.5 mg/kg/hour

Route: Slow intravenous injection, or intravenous infusion in glucose injection or sodium chloride injection

Frequency: Loading dose once, followed by continuous intravenous maintenance infusion (mg/kg/hour)

Max: Rate must not exceed 25 mg aminophylline per minute (section 4.2/4.4). Therapeutic serum theophylline 10-20 micrograms/ml; levels above 20 micrograms/ml are often associated with toxic effects (a range of 5-15 micrograms/ml may be effective with fewer adverse effects)

Narrow therapeutic index — cautious individual dose determination is essential and serum theophylline levels must be monitored. If acute adverse effects occur while the loading dose is being infused, the infusion may be stopped for 5-10 minutes or given at a slower rate. MAINTENANCE INFUSION RATES from the SPC table: children 6 months to 9 years 1 mg/kg/hour; children 10-16 years and young adult smokers 0.8 mg/kg/hour; otherwise healthy non-smoking adults 0.5 mg/kg/hour; elderly patients 0.3 mg/kg/hour. PATIENTS ALREADY ON THEOPHYLLINE: determine the time, route and dosage form of the last dose where possible; loading doses are based on the expectation that 0.5 mg/kg (lean body weight) of theophylline gives a 1 microgram/ml rise in serum theophylline — the loading dose should be deferred until a serum theophylline concentration can be obtained, or the clinician must carefully select a dose weighing benefits and risks; the maintenance rates above may then be considered. Administer cautiously to patients over 55 years. Clearance is decreased in cardiac failure, COPD, renal or hepatic dysfunction and chronic alcoholism; smokers have a shorter theophylline half-life and may require larger doses. Monitor serum potassium, especially with beta2-agonists, corticosteroids or diuretics, or in hypoxia.

Paediatric dose

Dose: 1 mg/kg

Route: Intravenous infusion

Frequency: Per hour, as a continuous maintenance infusion (1 mg/kg/hour)

Max: Not stated as a paediatric ceiling in section 4.2; infusion rate must not exceed 25 mg aminophylline per minute and serum theophylline should be kept within 10-20 micrograms/ml

SPC maintenance rate for children 6 months to 9 years is 1 mg/kg/hour; children 10-16 years of age (and young adult smokers) 0.8 mg/kg/hour. Aminophylline IV is NOT recommended in children under 6 months of age (reduced theophylline elimination, especially in neonates). No separate paediatric loading dose is stated in the SPC (the 5 mg/kg / 250-500 mg loading dose is given under 'Use in patients not currently receiving theophylline preparations'). Children are particularly susceptible to the effects of theophylline; seizures have been reported in children with plasma levels within the accepted therapeutic range. Verify all paediatric dosing against a children's formulary before administration.

Dose adjustments

Renal

No numeric adjustment stated. Section 4.4: aminophylline should be given with caution to patients with renal or hepatic dysfunction (as well as cardiac failure, COPD and chronic alcoholism) since clearance of aminophylline is decreased — monitor serum theophylline levels.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Paediatric weight-based calculator

Patient weight (kg)

Verify in a children's formulary

Contraindications

Hypersensitivity to ethylenediamine, or allergy to theophyllines, caffeine or theobromine, or to any excipient
Concomitant administration with other xanthine drugs (increased hazard of serious toxicity if aminophylline and/or theophylline are given simultaneously by more than one route or preparation)
Acute porphyria
Use of aminophylline IV in children under 6 months of age is not recommended

Side effects

Cardiac: palpitations, tachycardia, cardiac arrhythmias, hypotension — arrhythmias and hypotension may follow intravenous injection, particularly if given too rapidly, and sudden deaths have been reported
Nervous system/psychiatric: headache, confusion, restlessness, tremor, vertigo/dizziness, insomnia, anxiety; higher doses may cause maniacal behaviour, delirium and convulsions
Gastrointestinal: nausea, vomiting, abdominal pain, diarrhoea, gastro-oesophageal reflux, gastrointestinal bleeding
Metabolic: hypokalaemia, hypophosphataemia, hyponatraemia
Skin/hypersensitivity: rash, maculo-papular rash, erythema, pruritus, urticaria, exfoliative dermatitis; hypersensitivity reactions

Interactions

Fluvoxamine — concomitant use should usually be avoided; if unavoidable, halve the theophylline dose and monitor plasma theophylline closely
Cimetidine; macrolide antibiotics (e.g. erythromycin, clarithromycin); quinolone antibiotics (e.g. ciprofloxacin, norfloxacin); fluconazole; isoniazid — may increase plasma theophylline concentrations
Propranolol; calcium channel blockers (diltiazem, verapamil); mexiletine, propafenone; disulfiram; allopurinol in high doses (e.g. 600 mg daily) — may increase plasma theophylline concentrations
Oral contraceptives; interferon alfa; influenza vaccine; methotrexate; zafirlukast; tacrine; thiabendazole; thyroid hormones — may increase plasma theophylline concentrations
Beta2-agonists, corticosteroids and diuretics — monitor serum potassium (risk of hypokalaemia)

Clinical monograph

How it works

It produces bronchodilation through non-selective phosphodiesterase inhibition and adenosine receptor antagonism, increasing intracellular cyclic AMP in airway smooth muscle.

Prescribing in practice

It has a narrow therapeutic index and the intravenous loading dose must be omitted or reduced in patients already taking oral theophylline to avoid life-threatening toxicity such as seizures and arrhythmias.
Clearance is altered by many factors and drugs (for example reduced by ciprofloxacin, macrolides and in heart failure or liver disease; increased by enzyme inducers), requiring dose adjustment.
Give the loading dose as a slow intravenous infusion, as rapid administration can cause arrhythmias and profound hypotension.

Monitoring

Monitor ECG, serum potassium and theophylline concentrations, watching for tachyarrhythmia, hypokalaemia and signs of toxicity.

Counselling the patient

Always ask about current oral theophylline before any loading dose.
Report palpitations, nausea, tremor or agitation promptly as toxicity markers.
Combination with beta-agonists increases the risk of hypokalaemia.

Evidence & guidelines

Intravenous aminophylline is positioned as a second-line adjunct in BTS/SIGN and NICE acute asthma guidance after first-line bronchodilators and steroids.

Reference: BTS/SIGN Asthma Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pediatric Asthma Severity Score (PASS) · Paediatric Respiratory

Pathways