Drug interactions
Theophylline + Zileuton
Severity: Major
Theophylline and Zileuton: major interaction.
Last updated Sources: US FDA label
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Zileuton substantially reduces theophylline clearance, roughly doubling exposure in studies. This can cause theophylline toxicity including vomiting, tachyarrhythmia and seizures.
What this interaction means in plain words
Theophylline and Zileuton can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Theophylline belongs to Respiratory; Zileuton belongs to Respiratory.
Why it happens
Zileuton inhibits CYP1A2-mediated theophylline metabolism.
What to do
Reduce the theophylline dose by about half when starting zileuton and monitor serum theophylline concentrations closely.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
- Zileuton - FDA drug label (DailyMed) — openFDA / DailyMed
Other interactions of Theophylline
- Riociguat + Theophylline Contraindicated
- Adenosine + Theophylline Major
- Apalutamide + Theophylline Major
- Bupropion + Theophylline Major
- Carvedilol + Theophylline Major
- Cimetidine + Theophylline Major
Other interactions of Zileuton
- Fezolinetant + Zileuton Contraindicated
- Pimozide + Zileuton Contraindicated
- Alosetron + Zileuton Major
- Clozapine + Zileuton Major
- Lomitapide + Zileuton Major
- Lonafarnib + Zileuton Major
Frequently asked questions
Can I take Theophylline with Zileuton?
MediHelp rates the interaction as major. Theophylline and Zileuton can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Zileuton substantially reduces theophylline clearance, roughly doubling exposure in studies. This can cause theophylline toxicity including vomiting, tachyarrhythmia and seizures.
How serious is the interaction between Theophylline and Zileuton?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Reduce the theophylline dose by about half when starting zileuton and monitor serum theophylline concentrations closely.
What other medicines interact with Theophylline?
MediHelp also lists interactions of Theophylline with, for example, Riociguat, Adenosine, Apalutamide. The full list is on the Theophylline page.
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