Drug interactions
Fluconazole + Theophylline
Severity: Moderate
Fluconazole and Theophylline: moderate 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
Fluconazole may raise theophylline concentrations in some patients, raising the risk of nausea, tachycardia, arrhythmia and seizures. The effect is variable and is reported mainly at higher fluconazole doses.
What this interaction means in plain words
Fluconazole and Theophylline can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Fluconazole belongs to Anti Fungals; Theophylline belongs to Respiratory.
Why it happens
Fluconazole inhibits cytochrome P450 enzymes (including CYP1A2 and CYP3A4) that metabolize theophylline.
What to do
Check theophylline levels after starting fluconazole and reduce the theophylline dose if concentrations or toxicity signs rise. Recheck after stopping fluconazole.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Fluconazole and Theophylline, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
References
- Fluconazole - 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 Fluconazole
- Dihydroergotamine intranasal + Fluconazole Contraindicated
- Dihydroergotamine + Fluconazole Contraindicated
- Dofetilide + Fluconazole Contraindicated
- Domperidone + Fluconazole Contraindicated
- Dronedarone + Fluconazole Contraindicated
- Erythromycin + Fluconazole Contraindicated
Frequently asked questions
Can I take Fluconazole with Theophylline?
MediHelp rates the interaction as moderate. Fluconazole and Theophylline can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Fluconazole may raise theophylline concentrations in some patients, raising the risk of nausea, tachycardia, arrhythmia and seizures. The effect is variable and is reported mainly at higher fluconazole doses.
How serious is the interaction between Fluconazole and Theophylline?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check theophylline levels after starting fluconazole and reduce the theophylline dose if concentrations or toxicity signs rise. Recheck after stopping fluconazole.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
