Drug interactions
Carbamazepine + Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate
Severity: Major
Carbamazepine and Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate: 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
Carbamazepine accelerates the breakdown of both the estrogen and progestin components of combined oral contraceptives. Hormone exposure falls, which can cause breakthrough bleeding and contraceptive failure with unintended pregnancy. The effect persists for weeks after carbamazepine is stopped.
What this interaction means in plain words
Carbamazepine and Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate 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.
Why it happens
Carbamazepine induces hepatic and intestinal CYP3A4 (and other enzymes), increasing clearance of ethinylestradiol and levonorgestrel.
What to do
Avoid relying on the combined pill; use a non-enzyme-affected method such as a copper IUD or levonorgestrel IUD, or add a barrier method. Continue backup contraception for about 28 days after stopping carbamazepine.
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
Other interactions of Carbamazepine
- Artemether / lumefantrine + Carbamazepine Contraindicated
- Cabotegravir + Carbamazepine Contraindicated
- Carbamazepine + Delamanid Contraindicated
- Carbamazepine + Dienogest / estradiol valerate Contraindicated
- Carbamazepine + Doravirine Contraindicated
- Carbamazepine + Elbasvir / grazoprevir Contraindicated
Frequently asked questions
Can I take Carbamazepine with Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate?
MediHelp rates the interaction as major. Carbamazepine and Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate 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. Carbamazepine accelerates the breakdown of both the estrogen and progestin components of combined oral contraceptives. Hormone exposure falls, which can cause breakthrough bleeding and contraceptive failure with unintended pregnancy. The effect persists for weeks after carbamazepine is stopped.
How serious is the interaction between Carbamazepine and Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid relying on the combined pill; use a non-enzyme-affected method such as a copper IUD or levonorgestrel IUD, or add a barrier method. Continue backup contraception for about 28 days after stopping carbamazepine.
What other medicines interact with Carbamazepine?
MediHelp also lists interactions of Carbamazepine with, for example, Artemether / lumefantrine, Cabotegravir, Delamanid. The full list is on the Carbamazepine page.
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