Drug interactions
Fosamprenavir + Vincristine
Severity: Major
Fosamprenavir 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
Fosamprenavir (as amprenavir) inhibits CYP3A4, especially when ritonavir-boosted, and may raise vincristine exposure. This increases the risk of neurotoxicity and ileus.
What this interaction means in plain words
Fosamprenavir 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.
Why it happens
Amprenavir inhibits CYP3A4, reducing vincristine clearance.
What to do
Prefer an antiretroviral regimen without CYP3A inhibition during vincristine therapy. If coadministered, monitor for neuropathy and constipation and reduce the vincristine dose as needed.
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
Frequently asked questions
Can I take Fosamprenavir with Vincristine?
MediHelp rates the interaction as major. Fosamprenavir 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. Fosamprenavir (as amprenavir) inhibits CYP3A4, especially when ritonavir-boosted, and may raise vincristine exposure. This increases the risk of neurotoxicity and ileus.
How serious is the interaction between Fosamprenavir 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: Prefer an antiretroviral regimen without CYP3A inhibition during vincristine therapy. If coadministered, monitor for neuropathy and constipation and reduce the vincristine dose as needed.
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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