Drug interactions
Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate + Theophylline
Severity: Moderate
Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate and Theophylline: moderate 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
Combined oral contraceptives reduce theophylline clearance and can increase serum concentrations, with a risk of toxicity such as nausea, tachycardia, tremor and seizures. The effect varies between individuals.
What this interaction means in plain words
Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate 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.
Why it happens
Ethinylestradiol inhibits CYP1A2-mediated theophylline metabolism.
What to do
Monitor theophylline levels when starting or stopping the contraceptive and reduce the theophylline dose if levels rise.
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?
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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 Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate with Theophylline?
MediHelp rates the interaction as moderate. Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate 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. Combined oral contraceptives reduce theophylline clearance and can increase serum concentrations, with a risk of toxicity such as nausea, tachycardia, tremor and seizures. The effect varies between individuals.
How serious is the interaction between Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate 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: Monitor theophylline levels when starting or stopping the contraceptive and reduce the theophylline dose if levels rise.
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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