Drug interactions
Enzalutamide + Nirmatrelvir / ritonavir
Severity: Contraindicated
Enzalutamide and Nirmatrelvir / ritonavir: contraindicated interaction.
Last updated Sources: EMA 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
Enzalutamide lowers nirmatrelvir exposure through strong CYP3A4 induction, risking treatment failure and resistance. Ritonavir may also raise enzalutamide concentrations, and labeling contraindicates strong inducers.
What this interaction means in plain words
Enzalutamide and Nirmatrelvir / ritonavir are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Why it happens
CYP3A4 induction by enzalutamide lowers nirmatrelvir and ritonavir; ritonavir inhibits CYP3A4 and may raise enzalutamide.
What to do
Do not coadminister; use an alternative COVID-19 therapy such as remdesivir. Allow washout after stopping enzalutamide before starting nirmatrelvir/ritonavir.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Enzalutamide and Nirmatrelvir / ritonavir, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
References
Other interactions of Enzalutamide
- Doravirine + Enzalutamide Contraindicated
- Elbasvir / grazoprevir + Enzalutamide Contraindicated
- Ensitrelvir + Enzalutamide Contraindicated
- Enzalutamide + Fostemsavir Contraindicated
- Enzalutamide + Isavuconazonium Contraindicated
- Enzalutamide + Lenacapavir Contraindicated
Frequently asked questions
Can I take Enzalutamide with Nirmatrelvir / ritonavir?
MediHelp rates the interaction as contraindicated. Enzalutamide and Nirmatrelvir / ritonavir are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Enzalutamide lowers nirmatrelvir exposure through strong CYP3A4 induction, risking treatment failure and resistance. Ritonavir may also raise enzalutamide concentrations, and labeling contraindicates strong inducers.
How serious is the interaction between Enzalutamide and Nirmatrelvir / ritonavir?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Do not coadminister; use an alternative COVID-19 therapy such as remdesivir. Allow washout after stopping enzalutamide before starting nirmatrelvir/ritonavir.
What other medicines interact with Enzalutamide?
MediHelp also lists interactions of Enzalutamide with, for example, Doravirine, Elbasvir / grazoprevir, Ensitrelvir. The full list is on the Enzalutamide page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
