Theophylline Dosing

Theophylline and aminophylline loading and maintenance dosing with adjustment factors for age, smoking, cardiac disease, liver disease, and drug interactions.

Ideal Body Weight *

Theophylline distributes poorly into fat; use ideal body weight

Age *

years

Smoking Status *

Smoking increases theophylline clearance by ~50-100%

Cardiac Disease *

CHF reduces clearance; use 0.6 factor

Liver Disease

Yes

Hepatic dysfunction reduces clearance; use 0.6 factor

Interacting Drugs *

CYP inhibitors decrease clearance; inducers increase clearance

Drug Formulation *

Aminophylline contains 80% theophylline (multiply by 0.8)

Current Serum Theophylline Level

mcg/mL

For loading dose adjustment if patient has received theophylline in past 24 hours

Enter values and click Calculate to see results.

References

Theophylline - StatPearls — NCBI Bookshelf (2023). https://www.ncbi.nlm.nih.gov/books/NBK519024/
Theophylline Dosage Guide + Max Dose, Adjustments — Drugs.com (2025). https://www.drugs.com/dosage/theophylline.html
Theophylline formulas - RXkinetics — RXkinetics.com (2024). https://www.rxkinetics.com/kin_help/hlp_theophylline_formulas.htm
Switching between aminophylline and theophylline in adults — NHS SPS (2025). https://www.sps.nhs.uk/articles/switching-between-aminophylline-and-theophylline-in-adults/