Drug interactions
Atazanavir + Irinotecan
Severity: Major
Atazanavir and Irinotecan: 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
Atazanavir inhibits UGT1A1 and CYP3A4, which handle SN-38 glucuronidation and irinotecan oxidation. SN-38 exposure may rise, increasing severe diarrhea and neutropenia.
What this interaction means in plain words
Atazanavir and Irinotecan 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.
Atazanavir belongs to Anti Virals; Irinotecan belongs to Oncology.
Why it happens
Inhibition of UGT1A1-mediated SN-38 glucuronidation and CYP3A4 metabolism increases active SN-38 exposure.
What to do
Avoid the combination; use an alternative antiretroviral if feasible. If unavoidable, monitor closely for diarrhea 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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Other interactions of Irinotecan
- Clozapine + Irinotecan Contraindicated
- Irinotecan + Sacituzumab govitecan Contraindicated
- Adenovirus types 4 and 7 live + Irinotecan Major
- Apalutamide + Irinotecan Major
- Carbamazepine + Irinotecan Major
- Clarithromycin + Irinotecan Major
Other interactions of Atazanavir
- Alfuzosin + Atazanavir Contraindicated
- Atazanavir + Avanafil Contraindicated
- Atazanavir + Dronedarone Contraindicated
- Atazanavir + Eletriptan Contraindicated
- Atazanavir + Eplerenone Contraindicated
- Atazanavir + Ergotamine Contraindicated
Frequently asked questions
Can I take Atazanavir with Irinotecan?
MediHelp rates the interaction as major. Atazanavir and Irinotecan 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. Atazanavir inhibits UGT1A1 and CYP3A4, which handle SN-38 glucuronidation and irinotecan oxidation. SN-38 exposure may rise, increasing severe diarrhea and neutropenia.
How serious is the interaction between Atazanavir and Irinotecan?
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; use an alternative antiretroviral if feasible. If unavoidable, monitor closely for diarrhea 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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