Aminophylline

What it is and how it works

Mechanism of Action: Theophylline has two distinct actions in the airways of patients with reversible obstruction; smooth muscle relaxation (i.e., bronchodilation) and suppression of the response of the airways to stimuli (i.e., nonbronchodilator prophylactic effects). While the mechanisms of action of theophylline are not known with certainty, studies in animals suggest that bronchodilation is mediated by the inhibition of two isozymes of phosphodiesterase (PDE III and, to a lesser extent, PDE IV), while nonbronchodilator prophylactic actions are probably mediated through one or more different molecular mechanisms, that do not involve inhibition of PDE III or antagonism of adenosine recepto…

Indications

INDICATIONS AND USAGE Intravenous theophylline is indicated as an adjunct to inhaled beta-2 selective agonists and systemically administered corticosteroids for the treatment of acute exacerbations of the symptoms and reversible airflow obstruction associated with asthma and other chronic lung diseases, e.g., emphysema and chronic bronchitis.

Dosage and administration (summary)

DOSAGE AND ADMINISTRATION General Considerations: The steady-state serum theophylline concentration is a function of the infusion rate and the rate of theophylline clearance in the individual patient. Because of marked individual differences in the rate of theophylline clearance, the dose required to achieve a serum theophylline concentration in the 10-20 mcg/mL range varies fourfold among otherwise similar patients in the absence of factors known to alter theophylline clearance. For a given population there is no single theophylline dose that will provide both safe and effective serum concentrations for all patients.

Contraindications

CONTRAINDICATIONS Aminophylline is contraindicated in patients with a history of hypersensitivity to theophylline or other components in the product including ethylenediamine.

Warnings and precautions

WARNINGS Concurrent Illness: Theophylline should be used with extreme caution in patients with the following clinical conditions due to the increased risk of exacerbation of the concurrent condition: Active peptic ulcer disease Seizure disorders Cardiac arrhythmias (not including bradyarrhythmias) Conditions That Reduce Theophylline Clearance: There are several readily identifiable causes of reduced theophylline clearance. If the infusion rate is not appropriately reduced in the presence of these risk factors, severe and potentially fatal theophylline toxicity can occur.

Pregnancy

Pregnancy: There are no adequate and well controlled studies in pregnant women. Additionally, there are no teratogenicity studies in nonrodents (e.g., rabbits). Theophylline was not shown to be teratogenic in CD-1 mice at oral doses up to 400 mg/kg, approximately 2.0 times the human dose on a mg/m 2 basis or in CD-1 rats at oral doses up to 260 mg/…

Storage and supply

HOW SUPPLIED Aminophylline Injection, USP 25 mg/mL is supplied in single-dose container as follows: Unit of Sale Total Strength/Total Volume (Concentration) NDC 84549-922-01 500 mg/20 mL (25 mg/mL) Store at 20 to 25°C (68 to 77°F). PROTECT FROM LIGHT. Store in carton until time of use. SINGLE-DOSE CONTAINER. Discard unused portion.

Source: Aminophylline (Aminophylline) — US FDA prescribing information, 2025-12-18, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.