Drug interactions
Desogestrel-ethinyl estradiol + Primidone
Severity: Major
Desogestrel-ethinyl estradiol and Primidone: major interaction.
Last updated Sources: UK SmPC
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
Primidone is metabolized to phenobarbital and induces hepatic enzymes, lowering contraceptive hormone levels. Breakthrough bleeding and contraceptive failure may result.
What this interaction means in plain words
Desogestrel-ethinyl estradiol and Primidone 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.
Desogestrel-ethinyl estradiol belongs to Endocrine; Primidone belongs to Central Nervous System.
Why it happens
Enzyme induction (CYP3A4 and others) by primidone and its metabolite phenobarbital increases hormone clearance.
What to do
Avoid combined oral contraceptives; use a copper IUD, levonorgestrel IUS or DMPA, and keep the alternative for several weeks after stopping.
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 Desogestrel-ethinyl estradiol
- Desogestrel-ethinyl estradiol + Fezolinetant Contraindicated
- Aminocaproic acid + Desogestrel-ethinyl estradiol Major
- Amobarbital + Desogestrel-ethinyl estradiol Major
- Anastrozole + Desogestrel-ethinyl estradiol Major
- Apalutamide + Desogestrel-ethinyl estradiol Major
- Atazanavir + Desogestrel-ethinyl estradiol Major
Other interactions of Primidone
- Lorlatinib + Primidone Contraindicated
- Lurasidone + Primidone Contraindicated
- Primidone + Ranolazine Contraindicated
- Primidone + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
- Primidone + Voriconazole Contraindicated
- Abiraterone + Primidone Major
Frequently asked questions
Can I take Desogestrel-ethinyl estradiol with Primidone?
MediHelp rates the interaction as major. Desogestrel-ethinyl estradiol and Primidone 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. Primidone is metabolized to phenobarbital and induces hepatic enzymes, lowering contraceptive hormone levels. Breakthrough bleeding and contraceptive failure may result.
How serious is the interaction between Desogestrel-ethinyl estradiol and Primidone?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid combined oral contraceptives; use a copper IUD, levonorgestrel IUS or DMPA, and keep the alternative for several weeks after stopping.
What other medicines interact with Desogestrel-ethinyl estradiol?
MediHelp also lists interactions of Desogestrel-ethinyl estradiol with, for example, Fezolinetant, Aminocaproic acid, Amobarbital. The full list is on the Desogestrel-ethinyl estradiol page.
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