aminophylline hydrate: clinical use

Prescribing considerations

• Narrow therapeutic index: review previous theophylline or aminophylline exposure and interacting medicines before administration.
• Use particular caution with older patients and people with cardiac failure, hepatic or renal dysfunction, seizure history, acute febrile illness, severe hypoxaemia or chronic alcohol use.
• Clearance can change with smoking status, intercurrent illness and interacting medicines.
• Avoid rapid intravenous administration because cardiovascular and central nervous system toxicity may occur.

Contraindications and cautions

• Hypersensitivity to aminophylline, ethylenediamine, theophyllines, caffeine, theobromine or an excipient
• Concurrent administration of another xanthine
• Acute porphyria

Monitoring

• Assess for nausea, vomiting, tremor, palpitations, arrhythmia, hypotension, agitation or seizures.
• Monitor plasma theophylline concentrations when clinically indicated, including around interacting medicines or changes in smoking status.
• Monitor potassium, particularly with beta-2 agonists, corticosteroids, diuretics, hypoxia or severe asthma.
• Consider liver function and renal/electrolyte assessment, with closer surveillance in pregnancy, older age, heart failure or hepatic impairment.

Clinical pharmacology

Aminophylline supplies theophylline, which relaxes bronchial smooth muscle. Theophylline is largely metabolised in the liver, with substantial variation between individuals; smoking increases its clearance. It is distributed widely and crosses the placenta and enters breast milk.

Formulation and product differences

• The selected product is a clear sterile solution intended for intravenous injection or infusion.
• It contains ethylenediamine hydrate and water for injections.
• Any unused solution from an opened ampoule should be discarded.

Injection

Route: Parenteral

Strengths: 25 mg/mL