What the FDA labels say about taking them together
Irinotecan and ritonavir
Irinotecan's FDA label of May 12, 2026 names ritonavir in its drug interactions section; the ritonavir label PlainMeds reads does not name irinotecan. The irinotecan label: “Co-administration of ONIVYDE with other inhibitors of CYP3A4 or UGT1A1 may increase systemic exposure to irinotecan or SN-38.”
Check it at the source: the irinotecan FDA label on DailyMed (effective May 12, 2026, Pharmacia & Upjohn Company LLC); the ritonavir FDA label on DailyMed (effective July 23, 2026, AbbVie Inc.).
What does the irinotecan label say about ritonavir?
Irinotecan label, drug interactionsCoadministration 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.
Source: FDA drug label (Onivyde, NDA207793), Ipsen Biopharmaceuticals, Inc., effective March 3, 2025 (SPL set c8b58efa-1820-48a4-b70d-62918fc4abfc), via openFDA
Source: FDA drug label (Camptosar), NDA020571 (Pfizer Inc), as published by Pharmacia & Upjohn Company LLC, effective May 12, 2026 (SPL set e518dfc6-7e93-4fee-a66c-51e1ab71c056), via openFDA; the full label on DailyMed
What does the ritonavir label say about irinotecan?
Ritonavir's label (effective July 23, 2026) does not name irinotecan in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Norvir), AbbVie Inc., effective July 23, 2026 (SPL set 2849298e-de6e-47bb-8194-56e075b33fc3), 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
| Irinotecan | Ritonavir | |
|---|---|---|
| Labeled for | Colorectal cancer | HIV |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | n/a | $0.607 per tablet 100 mg tablet |
| Shortage now | A presentation being discontinued | A presentation being discontinued |
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