Yes. 16 FDA-approved labels for Irinotecan carry a boxed warning, and its subject is diarrhea and myelosuppression. A boxed warning is the most serious warning the FDA requires on a prescription label. It is applied to the drug and to the situations in which it is used, not to any particular person taking it.
What the warning says
Below is how the Irinotecan warning opens on one specific label, identified underneath it. Of the 16 Irinotecan labels sampled, 12 carried materially different wordings, and this was the most common, used by 3 of them.
WARNING: DIARRHEA and MYELOSUPPRESSION • Early and late forms of diarrhea can occur. Early diarrhea may be accompanied by cholinergic symptoms which may be prevented or ameliorated by atropine. Late diarrhea can be life threatening and should be treated promptly with loperamide. Monitor patients with diarrhea and give fluid and electrolytes as needed. Institute antibiotic therapy if patients develop ileus, fever, or severe neutropenia. Interrupt irinotecan hydrochloride injection and reduce subsequent doses if severe diarrhea occurs [see Dosage and Administration (2.2) and Warnings and Precautions (5.1) ] . • Severe myelosuppression may occur [see Warnings and Precautions (5.2) ] .
IRINOTECAN HYDROCHLORIDE, Apotex Corp., label version effective 28 June 2024. Opening of the warning; read the full label on DailyMed.Why the wording differs between manufacturers
There is no single official text of a boxed warning. The FDA sets what a warning must cover, and each manufacturer writes its own label within that. Of the 16 Irinotecan labels sampled for this page, 12 carried materially different wordings of the same warning, and the version quoted above was used by 3 of them.
The hazard does not change between those 12 versions. Only the sentences do, which is why a refill from a different manufacturer can carry warning text that reads differently without anything about Irinotecan or its risks having changed.
Irinotecan is dispensed under 16 current FDA labels despite this warning, which is the point worth holding onto: a boxed warning is a disclosure requirement, not a verdict. What a boxed warning does and does not mean sets out the distinction.
Common questions
Does Irinotecan have a black box warning?
Yes. 16 FDA-approved labels for Irinotecan carry a boxed warning, and its subject is diarrhea and myelosuppression. A boxed warning is the strongest warning the FDA requires on a prescription label, and it is applied to the drug, not to any individual taking it.
What does the Irinotecan boxed warning say?
The wording is set by each manufacturer within FDA requirements, so it varies. In the version quoted on this page, taken from a label effective 28 June 2024, the warning concerns diarrhea and myelosuppression. The full text is linked so the exact version can be read rather than summarised.
Does the Irinotecan boxed warning mean the drug is unsafe or being withdrawn?
No. It means the FDA requires the risk of diarrhea and myelosuppression to be communicated prominently so prescribers weigh it explicitly. Irinotecan remains FDA-approved and is dispensed under 16 current labels. A boxed warning is a disclosure requirement, not a judgement that a drug should not be used.
Why do different pharmacies show different warning text for the same drug?
Because each manufacturer writes its own label within the FDA's requirements. Of 16 Irinotecan labels sampled here, 12 carried materially different wordings of the same warning. The hazard described is the same; the sentences are not. This is a common source of confusion when a prescription is refilled with a different manufacturer's product.
Should I stop taking Irinotecan because of this warning?
This page does not answer that and cannot. The warning about diarrhea and myelosuppression is written for a prescriber deciding whether Irinotecan suits a particular patient, and stopping a prescribed medicine carries its own risks that this page knows nothing about. Raise it with the prescriber or a pharmacist, who can see the whole picture.
Where this page's information comes from
The quotation above is from one Irinotecan label, linked below by its DailyMed set identifier so the exact version can be opened rather than taken on trust. The figure of 16 labels, and the count of 12 distinct wordings among 16 sampled, were computed from the openFDA labelling API on 30 August 2026.
- IRINOTECAN HYDROCHLORIDE prescribing information, Apotex Corp., effective 28 June 2024.
- openFDA drug labelling API, the source of the label counts and variant counts on this page.
Labels are revised over time. The version linked above is the one this page was written against, and a newer revision may differ. Counts reflect the labels present in openFDA on the retrieval date.