Drug interactions
Ethinyl estradiol-levonorgestrel + Nirmatrelvir / ritonavir
Severity: Moderate
Ethinyl estradiol-levonorgestrel and Nirmatrelvir / ritonavir: 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
The ritonavir component may lower ethinyl estradiol exposure during and shortly after the five-day course. Contraceptive protection may be slightly reduced.
What this interaction means in plain words
Ethinyl estradiol-levonorgestrel and Nirmatrelvir / ritonavir 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.
Why it happens
Ritonavir probably induces enzymes such as glucuronidation and CYP pathways; the exact mechanism is not established.
What to do
Advise an additional non-hormonal contraceptive method for the remainder of the cycle after the course. Counsel the patient regarding missed-dose guidance.
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-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
Frequently asked questions
Can I take Ethinyl estradiol-levonorgestrel with Nirmatrelvir / ritonavir?
MediHelp rates the interaction as moderate. Ethinyl estradiol-levonorgestrel and Nirmatrelvir / ritonavir 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. The ritonavir component may lower ethinyl estradiol exposure during and shortly after the five-day course. Contraceptive protection may be slightly reduced.
How serious is the interaction between Ethinyl estradiol-levonorgestrel and Nirmatrelvir / ritonavir?
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 for the remainder of the cycle after the course. Counsel the patient regarding missed-dose guidance.
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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