Drug interactions
Carbamazepine + Norelgestromin
Severity: Major
Carbamazepine and Norelgestromin: 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 lowers norelgestromin exposure from the contraceptive patch, so the patch may fail to prevent ovulation. This increases the chance of unintended pregnancy.
What this interaction means in plain words
Carbamazepine and Norelgestromin 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 CYP3A4 and increases clearance of norelgestromin and ethinylestradiol.
What to do
Use a non-hormonal or enzyme-independent method such as an IUD instead of the patch. If the patch is continued, add a barrier method and continue it for 28 days after carbamazepine is stopped.
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 Norelgestromin?
MediHelp rates the interaction as major. Carbamazepine and Norelgestromin 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 lowers norelgestromin exposure from the contraceptive patch, so the patch may fail to prevent ovulation. This increases the chance of unintended pregnancy.
How serious is the interaction between Carbamazepine and Norelgestromin?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use a non-hormonal or enzyme-independent method such as an IUD instead of the patch. If the patch is continued, add a barrier method and continue it for 28 days after carbamazepine is stopped.
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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