Drug interactions
Ketoconazole + Vincristine
Severity: Major
Ketoconazole 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
Ketoconazole can raise vincristine concentrations and has been associated with severe neurotoxicity, including neuropathy, seizures, and paralytic ileus. The risk is notable because vincristine has a narrow therapeutic index.
What this interaction means in plain words
Ketoconazole 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.
Ketoconazole belongs to Anti Fungals; Vincristine belongs to Oncology.
Why it happens
Ketoconazole inhibits CYP3A4 and P-glycoprotein, reducing vincristine clearance.
What to do
Avoid azole antifungals such as ketoconazole with vincristine and choose an alternative, such as an echinocandin. If unavoidable, monitor closely for neurotoxicity and constipation.
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 Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole Contraindicated
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
Frequently asked questions
Can I take Ketoconazole with Vincristine?
MediHelp rates the interaction as major. Ketoconazole 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. Ketoconazole can raise vincristine concentrations and has been associated with severe neurotoxicity, including neuropathy, seizures, and paralytic ileus. The risk is notable because vincristine has a narrow therapeutic index.
How serious is the interaction between Ketoconazole 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 azole antifungals such as ketoconazole with vincristine and choose an alternative, such as an echinocandin. If unavoidable, monitor closely for neurotoxicity and constipation.
What other medicines interact with Ketoconazole?
MediHelp also lists interactions of Ketoconazole with, for example, Alfuzosin, Alprazolam, Avanafil. The full list is on the Ketoconazole page.
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