Drug interactions
Ethinyl estradiol-norgestimate + Lamotrigine
Severity: Major
Ethinyl estradiol-norgestimate and Lamotrigine: 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
Estrogen-containing contraceptives substantially lower lamotrigine concentrations, which can reduce seizure or mood control. Levels rise during the pill-free week, so toxicity such as dizziness, diplopia and ataxia can occur then. Stopping the contraceptive can cause lamotrigine levels to rise.
What this interaction means in plain words
Ethinyl estradiol-norgestimate and Lamotrigine 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.
Ethinyl estradiol-norgestimate belongs to Endocrine; Lamotrigine belongs to Central Nervous System.
Why it happens
Ethinyl estradiol induces glucuronidation (UGT1A4) of lamotrigine, increasing its clearance.
What to do
Monitor seizure control or mood and lamotrigine levels, and adjust the lamotrigine dose when starting or stopping the contraceptive. Consider continuous active-pill dosing to avoid fluctuations in the pill-free week.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Ethinyl estradiol-norgestimate and Lamotrigine, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
Other interactions of Ethinyl estradiol-norgestimate
- Ethinyl estradiol-norgestimate + Fezolinetant Contraindicated
- Ethinyl estradiol-norgestimate + Ombitasvir / paritaprevir / ritonavir and dasabuvir Contraindicated
- Ethinyl estradiol-norgestimate + Tranexamic acid Contraindicated
- Aminocaproic acid + Ethinyl estradiol-norgestimate Major
- Amobarbital + Ethinyl estradiol-norgestimate Major
- Anastrozole + Ethinyl estradiol-norgestimate Major
Other interactions of Lamotrigine
Frequently asked questions
Can I take Ethinyl estradiol-norgestimate with Lamotrigine?
MediHelp rates the interaction as major. Ethinyl estradiol-norgestimate and Lamotrigine 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. Estrogen-containing contraceptives substantially lower lamotrigine concentrations, which can reduce seizure or mood control. Levels rise during the pill-free week, so toxicity such as dizziness, diplopia and ataxia can occur then. Stopping the contraceptive can cause lamotrigine levels to rise.
How serious is the interaction between Ethinyl estradiol-norgestimate and Lamotrigine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor seizure control or mood and lamotrigine levels, and adjust the lamotrigine dose when starting or stopping the contraceptive. Consider continuous active-pill dosing to avoid fluctuations in the pill-free week.
What other medicines interact with Ethinyl estradiol-norgestimate?
MediHelp also lists interactions of Ethinyl estradiol-norgestimate with, for example, Fezolinetant, Ombitasvir / paritaprevir / ritonavir and dasabuvir, Tranexamic acid. The full list is on the Ethinyl estradiol-norgestimate page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
