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RESPIRATORY SYSTEM › DRUGS FOR OBSTRUCTIVE AIRWAY DISEASES › OTHER SYSTEMIC DRUGS FOR OBSTRUCTIVE AIRWAY DISEASES › Xanthines
theophylline
R03DA04
Forms & Strengths
- Oral tablets 100 mg, 200 mg, 300 mg
- Extended‑release tablets 200 mg, 300 mg
- Capsules 100 mg
- Oral syrup 100 mg/5 mL
- Injectable solution 5 mg/mL
Adult Dosing
- 300‑600 mg PO daily in divided doses (target serum 10‑20 µg/mL)
- Loading dose 5 mg/kg IV over 20 min then 300 mg PO
- Acute exacerbation IV infusion 0.5 mg/kg load then 0.25 mg/kg/hr
Pediatric Dosing
- >6 mo: loading 5 mg/kg IV then 5‑10 mg/kg/day PO q12h
- 6‑12 yr: loading 5 mg/kg IV then 6‑10 mg/kg/day PO divided q12h
- Target serum 10‑20 µg/mL; neonates contraindicated
Indications
- Chronic asthma maintenance
- COPD maintenance therapy
- Apnea of prematurity (IV)
- Off‑label: bronchopulmonary dysplasia
Mechanism of Action
- Non‑selective phosphodiesterase inhibition → ↑ cAMP → bronchodilation
- Adenosine‑receptor antagonism → central respiratory stimulation
Contraindications
- Hypersensitivity to theophylline
- Active peptic ulcer disease
- Uncontrolled arrhythmias or recent MI
- Severe hepatic impairment
- Concurrent potent CYP1A2 inhibitors at high dose
Adverse Reactions
- Nausea, vomiting, abdominal pain
- Headache, insomnia, tremor
- Tachyarrhythmia, hypotension
- Seizures (high levels)
- Photosensitivity, leukopenia
Drug Interactions
- CYP1A2 inhibitors (cimetidine, fluoroquinolones, macrolides, zileuton) ↑ levels
- CYP1A2 inducers (rifampin, carbamazepine, smoking) ↓ levels
- Warfarin ↑ INR
- Oral contraceptives ↓ efficacy
- β‑agonists additive tachycardia
- Allopurinol ↑ theophylline levels
- Zidovudine ↑ toxicity
Curated Content: Needs Vetting Before Put to Clinical Use