Drug interactions
Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate + Topiramate
Severity: Major
Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate and Topiramate: major 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
Topiramate, particularly at higher daily doses, can lower ethinylestradiol exposure and may reduce the reliability of combined hormonal contraception. This can lead to breakthrough bleeding and an increased risk of contraceptive failure, which is especially important because topiramate is teratogenic.
What this interaction means in plain words
Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate and Topiramate 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
Dose-dependent weak induction of CYP3A4 and possibly other pathways, which increases the metabolism of ethinylestradiol.
What to do
Use a non-hormonal or highly effective alternative such as an intrauterine device, or add a barrier method. Review contraceptive adequacy if breakthrough bleeding occurs, especially with topiramate doses above 200 mg daily.
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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Other interactions of Topiramate
Frequently asked questions
Can I take Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate with Topiramate?
MediHelp rates the interaction as major. Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate and Topiramate 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. Topiramate, particularly at higher daily doses, can lower ethinylestradiol exposure and may reduce the reliability of combined hormonal contraception. This can lead to breakthrough bleeding and an increased risk of contraceptive failure, which is especially important because topiramate is teratogenic.
How serious is the interaction between Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate and Topiramate?
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 highly effective alternative such as an intrauterine device, or add a barrier method. Review contraceptive adequacy if breakthrough bleeding occurs, especially with topiramate doses above 200 mg daily.
What other medicines interact with Topiramate?
MediHelp also lists interactions of Topiramate with, for example, Benzhydrocodone / acetaminophen, Buprenorphine long-acting, Buprenorphine subdermal implant. The full list is on the Topiramate page.
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