What the FDA labels say about taking them together
Atazanavir and ivosidenib
Atazanavir's FDA label of August 6, 2025 names ivosidenib in its contraindications section; the ivosidenib label PlainMeds reads does not name atazanavir. The atazanavir label: “Coadministration of ivosidenib with REYATAZ is contraindicated due to the potential for loss of virologic response and risk of serious adverse events such as QT interval prolongation.”
Check it at the source: the atazanavir FDA label on DailyMed (effective August 6, 2025, Aurobindo Pharma Limited); the ivosidenib FDA label on DailyMed (effective December 22, 2025, Servier Pharmaceutical LLC).
What does the atazanavir label say about ivosidenib?
Atazanavir label, contraindicationsDrug Class: Antineoplastics; Drugs within class that are contraindicated with atazanavir capsules: Apalutamide, encorafenib, irinotecan, ivosidenib
Atazanavir label, drug interactionsConcomitant Drug Class/Specific Drugs: Antineoplastics: irinotecan apalutamide ivosidenib encorafenib; Effect on Concentration of Atazanavir or Concomitant Drug: ↑ irinotecan ↓ atazanavir ↓ atazanavir ↑ ivosidenib ↓ atazanavir ↑ encorafenib; Clinical Comment: Coadministration of atazanavir with irinotecan is contraindicated. Atazanavir inhibits UGT1A1 and may interfere with the metabolism of irinotecan, resulting in increased irinotecan toxicities [see ]. Coadministration of atazanavir (with or without ritonavir) and apalutamide is contraindicated due to the potential for subsequent loss of virologic response and possible resistance to the class of protease inhibitors [see ]. …
Reyataz label (E.R. Squibb & Sons, L.L.C., December 5, 2024), drug interactionsConcomitant Drug Class/Specific Drugs: ivosidenib; Effect on Concentration of Atazanavir or Concomitant Drug: ↓ atazanavir ↑ ivosidenib; Clinical Comment: Coadministration of ivosidenib with REYATAZ (with or without ritonavir) is contraindicated due to the potential for loss of virologic response and risk of serious adverse events such as QT interval prolongation.
Source: FDA drug label (Reyataz, NDA021567), E.R. Squibb & Sons, L.L.C., effective December 5, 2024 (SPL set 165cff62-b284-4a27-a65d-9ec8a5bfcdd8), via openFDA
Source: FDA drug label (Atazanavir Sulfate), Aurobindo Pharma Limited, effective August 6, 2025 (SPL set 7fbea274-d6b5-4faa-bbf0-05fefab42114), via openFDA; the full label on DailyMed
What does the ivosidenib label say about atazanavir?
Ivosidenib's label (effective December 22, 2025) does not name atazanavir in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (TIBSOVO), Servier Pharmaceutical LLC, effective December 22, 2025 (SPL set 65d254c0-67ad-42c4-b972-ad463b755b2d), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Atazanavir | Ivosidenib | |
|---|---|---|
| Labeled for | HIV | Leukemia, lymphoma and myeloma |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $2.23 per capsule 300 mg capsule | n/a |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once