Drug interactions
Enzalutamide + Ritonavir
Severity: Major
Enzalutamide and Ritonavir: major 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
Ritonavir inhibits CYP3A4 and may raise enzalutamide exposure, increasing risk of seizures and other adverse effects. Enzalutamide in turn induces CYP3A4 and may lower ritonavir levels, reducing boosting.
What this interaction means in plain words
Enzalutamide and Ritonavir 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.
Enzalutamide belongs to Endocrine; Ritonavir belongs to Anti Virals.
Why it happens
Bidirectional CYP3A4 effects: ritonavir inhibits enzalutamide metabolism while enzalutamide induces ritonavir metabolism.
What to do
Avoid if possible; otherwise reduce the enzalutamide dose per labeling for strong CYP3A4 inhibitors and monitor HIV RNA and neurologic adverse effects.
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 Enzalutamide
- Doravirine + Enzalutamide Contraindicated
- Elbasvir / grazoprevir + Enzalutamide Contraindicated
- Ensitrelvir + Enzalutamide Contraindicated
- Enzalutamide + Fostemsavir Contraindicated
- Enzalutamide + Isavuconazonium Contraindicated
- Enzalutamide + Lenacapavir Contraindicated
Other interactions of Ritonavir
- Alfuzosin + Ritonavir Contraindicated
- Amiodarone + Ritonavir Contraindicated
- Avanafil + Ritonavir Contraindicated
- Colchicine + Ritonavir Contraindicated
- Dronedarone + Ritonavir Contraindicated
- Eletriptan + Ritonavir Contraindicated
Frequently asked questions
Can I take Enzalutamide with Ritonavir?
MediHelp rates the interaction as major. Enzalutamide and Ritonavir 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. Ritonavir inhibits CYP3A4 and may raise enzalutamide exposure, increasing risk of seizures and other adverse effects. Enzalutamide in turn induces CYP3A4 and may lower ritonavir levels, reducing boosting.
How serious is the interaction between Enzalutamide and Ritonavir?
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 if possible; otherwise reduce the enzalutamide dose per labeling for strong CYP3A4 inhibitors and monitor HIV RNA and neurologic adverse effects.
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.
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