Drug interactions
Ethinyl estradiol-drospirenone + Nirmatrelvir / ritonavir
Severity: Moderate
Ethinyl estradiol-drospirenone 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
Ritonavir can lower ethinyl estradiol exposure, which may reduce the contraceptive effectiveness of combined pills during a short course of treatment. Drospirenone exposure may be raised through CYP3A4 inhibition, adding some potassium-related concern. Unintended pregnancy is the main concern.
What this interaction means in plain words
Ethinyl estradiol-drospirenone 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 induces ethinyl estradiol metabolism (probably glucuronidation and CYP1A2/2C9) while inhibiting CYP3A4 metabolism of drospirenone.
What to do
Recommend an additional non-hormonal contraceptive method during the course and until the end of the cycle. Continue the pill as scheduled.
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-drospirenone
- Ethinyl estradiol-drospirenone + Fezolinetant Contraindicated
- Ethinyl estradiol-drospirenone + Ombitasvir / paritaprevir / ritonavir Contraindicated
- Ethinyl estradiol-drospirenone + Ombitasvir / paritaprevir / ritonavir and dasabuvir Contraindicated
- Ethinyl estradiol-drospirenone + Tranexamic acid Contraindicated
- Aminocaproic acid + Ethinyl estradiol-drospirenone Major
- Amobarbital + Ethinyl estradiol-drospirenone Major
Frequently asked questions
Can I take Ethinyl estradiol-drospirenone with Nirmatrelvir / ritonavir?
MediHelp rates the interaction as moderate. Ethinyl estradiol-drospirenone 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. Ritonavir can lower ethinyl estradiol exposure, which may reduce the contraceptive effectiveness of combined pills during a short course of treatment. Drospirenone exposure may be raised through CYP3A4 inhibition, adding some potassium-related concern. Unintended pregnancy is the main concern.
How serious is the interaction between Ethinyl estradiol-drospirenone 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: Recommend an additional non-hormonal contraceptive method during the course and until the end of the cycle. Continue the pill as scheduled.
What other medicines interact with Ethinyl estradiol-drospirenone?
MediHelp also lists interactions of Ethinyl estradiol-drospirenone with, for example, Fezolinetant, Ombitasvir / paritaprevir / ritonavir, Ombitasvir / paritaprevir / ritonavir and dasabuvir. The full list is on the Ethinyl estradiol-drospirenone page.
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