What the FDA labels say about taking them together

Irinotecan and rifampin

Irinotecan's FDA label of May 12, 2026 names rifampin in its drug interactions section; the rifampin label PlainMeds reads does not name irinotecan. The irinotecan label: “Avoid the use of strong CYP3A4 inducers if possible.”

Check it at the source: the irinotecan FDA label on DailyMed (effective May 12, 2026, Pharmacia & Upjohn Company LLC); the rifampin FDA label on DailyMed (effective February 11, 2026, Lupin Pharmaceuticals, Inc.).

What does the irinotecan label say about rifampin?

Irinotecan label, drug interactions
The appropriate starting dose for patients taking these or other strong inducers such as rifampin and rifabutin has not been defined.

Onivyde label (Ipsen Biopharmaceuticals, Inc., March 3, 2025), drug interactions
Avoid the use of strong CYP3A4 inducers (e.g., rifampin, phenytoin, carbamazepine, rifabutin, rifapentine, phenobarbital, St. John's wort) if possible.

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 rifampin label say about irinotecan?

Rifampin's label (effective February 11, 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 (rifampin), Lupin Pharmaceuticals, Inc., effective February 11, 2026 (SPL set b56004f0-f23d-47f6-80c7-39884fccbccc), 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

12Irinotecan generic labelers

13Rifampin generic labelers

	Irinotecan	Rifampin
Labeled for	Colorectal cancer	n/a
Boxed warning	Yes	No
Pharmacy cost (NADAC)	n/a	$0.679 per capsule 300 mg capsule
Shortage now	A presentation being discontinued	In shortage

Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)

What next?

Irinotecan: the full record
Rifampin: the full record
Check more medicines together: up to five at once