Drug interactions
Ritonavir + Vincristine
Severity: Major
Ritonavir and Vincristine: 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 P-gp, and vinca alkaloids given with it have caused severe neurotoxicity and ileus. Marked myelosuppression has also been reported.
What this interaction means in plain words
Ritonavir and Vincristine 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 belongs to Anti Virals; Vincristine belongs to Oncology.
Why it happens
Ritonavir inhibits CYP3A4 and P-gp, reducing vincristine clearance.
What to do
Avoid the combination and use an antiretroviral regimen without boosters during vincristine therapy where possible. If unavoidable, monitor closely for neurotoxicity and bowel obstruction and consider reducing the vincristine dose.
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 Vincristine
- Adenovirus types 4 and 7 live + Vincristine Contraindicated
- Apalutamide + Vincristine Major
- Atazanavir + Vincristine Major
- Ceritinib + Vincristine Major
- Chloramphenicol + Vincristine Major
- Clarithromycin + Vincristine Major
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 Ritonavir with Vincristine?
MediHelp rates the interaction as major. Ritonavir and Vincristine 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 P-gp, and vinca alkaloids given with it have caused severe neurotoxicity and ileus. Marked myelosuppression has also been reported.
How serious is the interaction between Ritonavir and Vincristine?
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 and use an antiretroviral regimen without boosters during vincristine therapy where possible. If unavoidable, monitor closely for neurotoxicity and bowel obstruction and consider reducing the vincristine dose.
What other medicines interact with Vincristine?
MediHelp also lists interactions of Vincristine with, for example, Adenovirus types 4 and 7 live, Apalutamide, Atazanavir. The full list is on the Vincristine page.
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