Drug interactions
Crizotinib + Ritonavir
Severity: Major
Crizotinib and Ritonavir: 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
Ritonavir is a strong CYP3A4 inhibitor that increases crizotinib exposure, raising the risk of QT prolongation, bradycardia and hepatotoxicity. Crizotinib may also raise ritonavir levels through P-glycoprotein inhibition.
What this interaction means in plain words
Crizotinib 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.
Crizotinib belongs to Oncology; Ritonavir belongs to Anti Virals.
Why it happens
Ritonavir inhibits CYP3A4 metabolism of crizotinib; crizotinib may inhibit P-gp efflux of ritonavir.
What to do
Avoid the combination where possible; if unavoidable, reduce the crizotinib dose per labeling and monitor ECG, electrolytes and liver function.
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 Crizotinib
- Crizotinib + Flibanserin Contraindicated
- Crizotinib + Lomitapide Contraindicated
- Crizotinib + Lonafarnib Contraindicated
- Crizotinib + Pimozide Contraindicated
- Crizotinib + Saquinavir Contraindicated
- Crizotinib + Thioridazine 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 Crizotinib with Ritonavir?
MediHelp rates the interaction as major. Crizotinib 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 is a strong CYP3A4 inhibitor that increases crizotinib exposure, raising the risk of QT prolongation, bradycardia and hepatotoxicity. Crizotinib may also raise ritonavir levels through P-glycoprotein inhibition.
How serious is the interaction between Crizotinib 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 the combination where possible; if unavoidable, reduce the crizotinib dose per labeling and monitor ECG, electrolytes and liver function.
What other medicines interact with Crizotinib?
MediHelp also lists interactions of Crizotinib with, for example, Flibanserin, Lomitapide, Lonafarnib. The full list is on the Crizotinib page.
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