Atazanavir and Irinotecan interaction
Atazanavir and Irinotecan: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Irinotecan (Camptosar) label · effective 2026-05-12
• Strong CYP3A4 Inhibitors: Do not administer strong CYP3A4 inhibitors with CAMPTOSAR.
Coadministration of CAMPTOSAR with other inhibitors of CYP3A4 (e.g., clarithromycin, indinavir, itraconazole, lopinavir, nefazodone, nelfinavir, ritonavir, saquinavir, telaprevir, voriconazole) or UGT1A1 (e.g., atazanavir, gemfibrozil, indinavir) may increase systemic exposure to irinotecan or SN-38.
Discontinue strong CYP3A4 inhibitors at least 1 week prior to starting CAMPTOSAR therapy.
From the Atazanavir (REYATAZ) label · effective 2024-12-05
…Carbamazepine, phenobarbital, phenytoin Antiarrhythmics Amiodarone (with ritonavir), quinidine (with ritonavir) Antimycobacterials Rifampin Antineoplastics Apalutamide, encorafenib, irinotecan, ivosidenib Antipsychotics Lurasidone (with ritonavir), pimozide Benzodiazepines Orally administered midazolam a , triazolam Ergot Derivatives Dihydroergotamine, ergonovine,…
Antineoplastics: irinotecan ↑ irinotecan Coadministration of REYATAZ with irinotecan is contraindicated.
Atazanavir inhibits UGT1A1 and may interfere with the metabolism of irinotecan, resulting in increased irinotecan toxicities [see Contraindications (4) ] . apalutamide ↓ atazanavir Coadministration of REYATAZ (with or without ritonavir) and apalutamide is contraindicated due to the potential for subsequent loss of virologic response and possible resistance to…
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.