Drug interactions
Grapefruit + Theophylline
Severity: Minor
Grapefruit and Theophylline: minor interaction.
Last updated
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
Grapefruit inhibits intestinal CYP3A4, but theophylline is mainly cleared by CYP1A2, so the effect is minimal. Clinically significant changes in theophylline levels are not expected.
What this interaction means in plain words
Grapefruit and Theophylline have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Why it happens
Weak CYP3A4 inhibition affects a minor theophylline pathway.
What to do
No action needed beyond awareness; check levels if toxicity occurs.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Theophylline
- Riociguat + Theophylline Contraindicated
- Adenosine + Theophylline Major
- Apalutamide + Theophylline Major
- Bupropion + Theophylline Major
- Carvedilol + Theophylline Major
- Cimetidine + Theophylline Major
Frequently asked questions
Can I take Grapefruit with Theophylline?
MediHelp rates the interaction as minor. Grapefruit and Theophylline have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Grapefruit inhibits intestinal CYP3A4, but theophylline is mainly cleared by CYP1A2, so the effect is minimal. Clinically significant changes in theophylline levels are not expected.
How serious is the interaction between Grapefruit and Theophylline?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No action needed beyond awareness; check levels if toxicity occurs.
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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