Drug interactions
Ethinyl estradiol-levonorgestrel + Nelfinavir
Severity: Major
Ethinyl estradiol-levonorgestrel and Nelfinavir: major interaction.
Last updated Sources: US FDA label
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
Nelfinavir lowers ethinyl estradiol exposure, which may reduce the efficacy of combined contraceptives. Progestin exposure may also change.
What this interaction means in plain words
Ethinyl estradiol-levonorgestrel and Nelfinavir 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-levonorgestrel belongs to Endocrine; Nelfinavir belongs to Anti Virals.
Why it happens
Induction of metabolic pathways, including glucuronidation and CYP enzymes, altering contraceptive hormone exposure.
What to do
Use an alternative or additional non-hormonal contraceptive method. Do not rely on the combined pill alone.
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 Ethinyl estradiol-levonorgestrel
- Ethinyl estradiol-levonorgestrel + Fezolinetant Contraindicated
- Ethinyl estradiol-levonorgestrel + Ombitasvir / paritaprevir / ritonavir and dasabuvir Contraindicated
- Ethinyl estradiol-levonorgestrel + Tranexamic acid Contraindicated
- Aminocaproic acid + Ethinyl estradiol-levonorgestrel Major
- Amobarbital + Ethinyl estradiol-levonorgestrel Major
- Anastrozole + Ethinyl estradiol-levonorgestrel Major
Other interactions of Nelfinavir
- Alfuzosin + Nelfinavir Contraindicated
- Avanafil + Nelfinavir Contraindicated
- Dronedarone + Nelfinavir Contraindicated
- Eletriptan + Nelfinavir Contraindicated
- Ergotamine + Nelfinavir Contraindicated
- Flibanserin + Nelfinavir Contraindicated
Frequently asked questions
Can I take Ethinyl estradiol-levonorgestrel with Nelfinavir?
MediHelp rates the interaction as major. Ethinyl estradiol-levonorgestrel and Nelfinavir 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. Nelfinavir lowers ethinyl estradiol exposure, which may reduce the efficacy of combined contraceptives. Progestin exposure may also change.
How serious is the interaction between Ethinyl estradiol-levonorgestrel and Nelfinavir?
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 an alternative or additional non-hormonal contraceptive method. Do not rely on the combined pill alone.
What other medicines interact with Ethinyl estradiol-levonorgestrel?
MediHelp also lists interactions of Ethinyl estradiol-levonorgestrel with, for example, Fezolinetant, Ombitasvir / paritaprevir / ritonavir and dasabuvir, Tranexamic acid. The full list is on the Ethinyl estradiol-levonorgestrel page.
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