Drug interactions
Istradefylline + Theophylline
Severity: Minor
Istradefylline 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
Istradefylline at 40 mg/day inhibits CYP3A4 and raises exposure to sensitive substrates. Theophylline is mainly a CYP1A2 substrate, so the effect is likely minor, though istradefylline is also an adenosine antagonist and may add pharmacodynamic stimulation.
What this interaction means in plain words
Istradefylline 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.
Istradefylline belongs to Central Nervous System; Theophylline belongs to Respiratory.
Why it happens
Weak CYP3A4 inhibition at higher istradefylline doses affects a minor theophylline metabolic pathway.
What to do
Monitor for theophylline adverse effects when istradefylline 40 mg/day is used and check serum levels if symptoms occur.
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
Other interactions of Istradefylline
Frequently asked questions
Can I take Istradefylline with Theophylline?
MediHelp rates the interaction as minor. Istradefylline 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. Istradefylline at 40 mg/day inhibits CYP3A4 and raises exposure to sensitive substrates. Theophylline is mainly a CYP1A2 substrate, so the effect is likely minor, though istradefylline is also an adenosine antagonist and may add pharmacodynamic stimulation.
How serious is the interaction between Istradefylline 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: Monitor for theophylline adverse effects when istradefylline 40 mg/day is used and check serum levels if symptoms occur.
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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