Oral (adults): 200–400 mg/day in divided doses or sustained-release preparation
Children: 10–16 mg/kg/day in divided doses
Target serum level: 10–20 µg/mL
Note: Dose must be individualized based on serum levels.
Route of Administration
Oral (immediate-release, sustained-release)
Mechanism of Action
Theophylline inhibits phosphodiesterase enzymes, increasing intracellular cAMP, leading to relaxation of bronchial smooth muscle. It also antagonizes adenosine receptors, contributing to bronchodilation and mild anti-inflammatory effects.
Common Adverse Effects
Nausea and vomiting
Gastric irritation
Headache
Tremor
Insomnia
Serious Adverse Effects
Cardiac arrhythmias
Seizures
Severe hypotension
Theophylline toxicity
Contraindications
Hypersensitivity to theophylline
Uncontrolled cardiac arrhythmias
Active peptic ulcer disease
Precautions
Narrow therapeutic index
Monitor serum theophylline levels regularly
Reduce dose in liver disease, heart failure, fever, elderly
Drug Interactions
Macrolides and fluoroquinolones – increase serum levels
Phenytoin, rifampicin – reduce serum levels
Caffeine – increased toxicity
Beta-agonists – additive tachycardia
Pregnancy & Lactation
Use with caution in pregnancy. Compatible with breastfeeding at therapeutic doses.
Patient Counseling
Take medication at the same time each day
Avoid excessive caffeine intake
Report nausea, vomiting, palpitations, or seizures immediately