Aminophylline

Methylxanthine Bronchodilator

Generic Name

Aminophylline

Drug Class

Methylxanthine bronchodilator (Theophylline derivative)

Indications

Acute severe asthma
Chronic obstructive pulmonary disease (COPD)
Apnea of prematurity (rare use)

Dosage

Acute severe asthma (IV loading): 5–6 mg/kg over 20–30 minutes (if not on theophylline)
Maintenance infusion: 0.5–1 mg/kg/hour (adjust by age and clinical response)
Oral (less common): Equivalent to theophylline dosing

Therapeutic serum level: 10–20 µg/mL

Route of Administration

Intravenous (preferred in emergencies), Oral

Mechanism of Action

Aminophylline relaxes bronchial smooth muscle by inhibiting phosphodiesterase, increasing intracellular cAMP. It also antagonizes adenosine receptors, resulting in bronchodilation and mild anti-inflammatory effects.

Common Adverse Effects

Nausea and vomiting
Headache
Tremor
Palpitations
Insomnia

Serious Adverse Effects

Cardiac arrhythmias
Seizures
Severe hypotension
Theophylline toxicity

Contraindications

Hypersensitivity to aminophylline or theophylline
Uncontrolled arrhythmias
Seizure disorders (relative)

Precautions

Narrow therapeutic index – monitor serum levels
Use cautiously in elderly, liver disease, heart failure
Reduce dose in fever, sepsis, or hepatic impairment

Drug Interactions

Macrolides (erythromycin) – increase toxicity
Fluoroquinolones (ciprofloxacin) – increase serum levels
Phenytoin, rifampicin – decrease serum levels
Beta-agonists – increased risk of tachycardia

Pregnancy & Lactation

Use with caution in pregnancy. Compatible with breastfeeding at therapeutic doses.

Patient Counseling

Report nausea, vomiting, palpitations, or seizures immediately
Avoid caffeine-containing products
Regular blood level monitoring may be required