Drug interactions
Ethinyl estradiol-norgestimate + Felbamate
Severity: Moderate
Ethinyl estradiol-norgestimate and Felbamate: moderate 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
Felbamate may lower exposure to the contraceptive steroids, and its labeling notes that it can reduce the effectiveness of hormonal contraceptives. Reduced hormone levels could lead to breakthrough bleeding and a risk of contraceptive failure.
What this interaction means in plain words
Ethinyl estradiol-norgestimate and Felbamate can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Ethinyl estradiol-norgestimate belongs to Endocrine; Felbamate belongs to Central Nervous System.
Why it happens
Felbamate is a weak CYP3A4 inducer and may accelerate metabolism of ethinyl estradiol and progestins, although the exact mechanism is not fully established.
What to do
Advise an additional non-hormonal contraceptive method while on felbamate and for a period after stopping it. Consider a method not affected by enzyme induction, such as an intrauterine device.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Felbamate
- Felbamate + Ulipristal Major
- Amisulpride + Felbamate Moderate
- Amitriptyline + Felbamate Moderate
- Apalutamide + Felbamate Moderate
- Asenapine + Felbamate Moderate
- Bosentan + Felbamate Moderate
Frequently asked questions
Can I take Ethinyl estradiol-norgestimate with Felbamate?
MediHelp rates the interaction as moderate. Ethinyl estradiol-norgestimate and Felbamate can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Felbamate may lower exposure to the contraceptive steroids, and its labeling notes that it can reduce the effectiveness of hormonal contraceptives. Reduced hormone levels could lead to breakthrough bleeding and a risk of contraceptive failure.
How serious is the interaction between Ethinyl estradiol-norgestimate and Felbamate?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Advise an additional non-hormonal contraceptive method while on felbamate and for a period after stopping it. Consider a method not affected by enzyme induction, such as an intrauterine device.
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.
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