Drug interactions
Irinotecan + Nelfinavir
Severity: Major
Irinotecan and Nelfinavir: 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
Nelfinavir inhibits CYP3A4 and may raise irinotecan and SN-38 exposure, increasing risk of severe diarrhoea and neutropenia. Nelfinavir may also reduce SN-38 glucuronidation.
What this interaction means in plain words
Irinotecan and Nelfinavir 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.
Irinotecan belongs to Oncology; Nelfinavir belongs to Anti Virals.
Why it happens
CYP3A4 inhibition, with possible UGT1A1 inhibition, reduces clearance of irinotecan and SN-38.
What to do
Avoid if possible by using an alternative antiretroviral. If necessary, monitor closely for diarrhoea and neutropenia and consider irinotecan dose reduction.
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 Irinotecan
- Clozapine + Irinotecan Contraindicated
- Irinotecan + Sacituzumab govitecan Contraindicated
- Adenovirus types 4 and 7 live + Irinotecan Major
- Apalutamide + Irinotecan Major
- Atazanavir + Irinotecan Major
- Carbamazepine + Irinotecan Major
Other interactions of Nelfinavir
- Alfuzosin + Nelfinavir Contraindicated
- Avanafil + Nelfinavir Contraindicated
- Dronedarone + Nelfinavir Contraindicated
- Eletriptan + Nelfinavir Contraindicated
- Ergotamine + Nelfinavir Contraindicated
- Flibanserin + Nelfinavir Contraindicated
Frequently asked questions
Can I take Irinotecan with Nelfinavir?
MediHelp rates the interaction as major. Irinotecan and Nelfinavir 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. Nelfinavir inhibits CYP3A4 and may raise irinotecan and SN-38 exposure, increasing risk of severe diarrhoea and neutropenia. Nelfinavir may also reduce SN-38 glucuronidation.
How serious is the interaction between Irinotecan and Nelfinavir?
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 if possible by using an alternative antiretroviral. If necessary, monitor closely for diarrhoea and neutropenia and consider irinotecan dose reduction.
What other medicines interact with Irinotecan?
MediHelp also lists interactions of Irinotecan with, for example, Clozapine, Sacituzumab govitecan, Adenovirus types 4 and 7 live. The full list is on the Irinotecan page.
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