What is the therapeutic range for theophylline?

Therapeutic range 5-15 mcg/mL (bronchodilation); toxicity begins >15-20 mcg/mL with nausea/tachycardia; severe toxicity (seizures, arrhythmias) >30 mcg/mL; lower target (8-12) recommended in elderly and cardiac patients.

What IV loading dose of aminophylline is used?

If no prior theophylline: 5 mg/kg aminophylline (4 mg/kg theophylline base) IV over 20 min; if patient on theophylline: check level and give partial load; maintenance 0.5-0.9 mg/kg/h depending on patient factors.

What drug interactions significantly increase theophylline levels?

Major inhibitors of CYP1A2 and CYP3A4: ciprofloxacin (50-100% increase), clarithromycin, cimetidine, mexiletine, fluvoxamine; smoking induces CYP1A2, reducing levels 30-50%; dose must be adjusted for all interactions.

How does hepatic failure affect theophylline clearance?

Theophylline clearance reduced 50-70% in severe hepatic cirrhosis; maintenance dose requires halving with careful TDM; also consider reducing dose in CHF, elderly patients, and those with pneumonia (inflammatory cytokines reduce CYP1A2).

What is the management of theophylline toxicity?

Activated charcoal (repeat-dose) adsorbs theophylline; beta-blockers (propranolol) for supraventricular tachycardia; benzodiazepines for seizures; hemodialysis or charcoal hemoperfusion for levels >80-90 mcg/mL or refractory toxicity.

Theophylline Dosing and Toxicity Calculator

Calculates theophylline loading dose and maintenance infusion for acute severe asthma, target serum levels, dose adjustments for hepatic failure and drug interactions, and toxicity management thresholds.

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Frequently Asked Questions

What is the therapeutic range for theophylline?

What IV loading dose of aminophylline is used?

What drug interactions significantly increase theophylline levels?

How does hepatic failure affect theophylline clearance?

What is the management of theophylline toxicity?