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# FDA Updates Safety Labels for Chemo Drugs
- URL: https://www.fdaweb.com/fda-updates-safety-labels-for-chemo-drugs/
- Published: 2026-02-05T12:00:00.000Z
- Updated: 2026-09-14T15:32:35.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5160618

FDA has updated the safety labeling for the widely used chemotherapy drugs capecitabine (Genentech’s Xeloda) and fluorouracil (multiple manufacturers) to strengthen warnings about the risk of serious and potentially fatal toxicities in patients with dihydropyrimidine dehydrogenase (DPD) deficiency. Capecitabine and fluorouracil are cornerstone chemotherapies used across a wide range of solid tumors, including colorectal, breast, gastric, and head and neck cancers.

In an agency [safety communication](https://www.fda.gov/drugs/resources-information-approved-drugs/safety-labeling-update-capecitabine-and-fluorouracil-5-fu-risks-associated-dihydropyrimidine?ref=fdaweb.com), healthcare providers were instructed to test patients for genetic variants of the DPYD gene before starting treatment with either drug, unless immediate therapy is required. The agency also urged clinicians to inform patients of the risks associated with DPD deficiency prior to initiating treatment.

DPD is the enzyme responsible for breaking down more than 80% of fluorouracil. Patients with certain genetic variants that result in little or no DPD activity can experience acute, early-onset toxicity, including severe mucositis, diarrhea, neutropenia, neurotoxicity, and death, when exposed to capecitabine or 5-FU, FDA says.

As part of the labeling update, agency-approved revisions to the Boxed Warning more clearly highlight the risk of serious adverse reactions or death in patients with complete DPD deficiency, according to the agency.

FDA says it will continue to monitor the safety of capecitabine and fluorouracil and assess the evolving evidence around DPD deficiency. Additional regulatory actions could be considered as new data emerge.