Drug interactions
Lamotrigine + Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate
Severity: Major
Lamotrigine and Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate: 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
Ethinylestradiol-containing contraceptives markedly lower lamotrigine concentrations, which may reduce seizure control. Levels rise during the hormone-free week, which can cause toxicity such as dizziness, diplopia and ataxia.
What this interaction means in plain words
Lamotrigine 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
Ethinylestradiol induces UDP-glucuronosyltransferase, increasing lamotrigine glucuronidation.
What to do
Increase the lamotrigine dose as needed guided by clinical response when starting the contraceptive, and reduce it when stopping. Monitor for toxicity in the hormone-free week and consider continuous hormone use or lamotrigine levels.
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 Lamotrigine
Frequently asked questions
Can I take Lamotrigine with Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate?
MediHelp rates the interaction as major. Lamotrigine 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. Ethinylestradiol-containing contraceptives markedly lower lamotrigine concentrations, which may reduce seizure control. Levels rise during the hormone-free week, which can cause toxicity such as dizziness, diplopia and ataxia.
How serious is the interaction between Lamotrigine 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: Increase the lamotrigine dose as needed guided by clinical response when starting the contraceptive, and reduce it when stopping. Monitor for toxicity in the hormone-free week and consider continuous hormone use or lamotrigine levels.
What other medicines interact with Lamotrigine?
MediHelp also lists interactions of Lamotrigine with, for example, Desogestrel-ethinyl estradiol, Divalproex, Dofetilide. The full list is on the Lamotrigine page.
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