Drug interactions
Regorafenib + Ritonavir
Severity: Major
Regorafenib and Ritonavir: major 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 strongly inhibits CYP3A4 and may raise regorafenib concentrations while lowering the active metabolites M-2 and M-5. The net effect on safety and efficacy is unpredictable. Labeling advises avoiding strong CYP3A4 inhibitors.
What this interaction means in plain words
Regorafenib 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.
Regorafenib belongs to Oncology; Ritonavir belongs to Anti Virals.
Why it happens
Ritonavir inhibits CYP3A4, reducing regorafenib metabolism and altering metabolite formation.
What to do
Avoid concomitant use and consider an antiretroviral without strong CYP3A4 inhibition. If unavoidable, monitor for hepatotoxicity, hand-foot reaction and hypertension.
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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Other interactions of Regorafenib
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 Regorafenib with Ritonavir?
MediHelp rates the interaction as major. Regorafenib 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 strongly inhibits CYP3A4 and may raise regorafenib concentrations while lowering the active metabolites M-2 and M-5. The net effect on safety and efficacy is unpredictable. Labeling advises avoiding strong CYP3A4 inhibitors.
How serious is the interaction between Regorafenib 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 concomitant use and consider an antiretroviral without strong CYP3A4 inhibition. If unavoidable, monitor for hepatotoxicity, hand-foot reaction and hypertension.
What other medicines interact with Regorafenib?
MediHelp also lists interactions of Regorafenib with, for example, Apalutamide, Atazanavir, Carbamazepine. The full list is on the Regorafenib page.
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