What causes severe 5-FU toxicity?

DPD (dihydropyrimidine dehydrogenase) deficiency affects 3–5% of patients and causes severe or fatal 5-FU toxicity at standard doses. DPYD genotyping before 5-FU administration is recommended in several European guidelines; initial dose reduction of 50% for DPYD*2A heterozygotes.

What is the recommended dose modification for grade 3 diarrhea?

Grade 3 diarrhea: hold 5-FU until recovery to grade 1 or baseline, then reduce dose by 25%. Grade 3 mucositis: delay until recovery, reduce by 25%. Grade 4 events or any life-threatening toxicity: discontinue 5-FU permanently.

5-FU Dose Reduction by Toxicity Grade

Guide 5-fluorouracil dose modification based on CTCAE toxicity grade for mucositis, diarrhea, hand-foot syndrome, and myelosuppression: grade 2 delay, grade 3 reduce, grade 4 discontinue.

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5-FU Dose Reduction by Toxicity Grade

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Frequently Asked Questions

What causes severe 5-FU toxicity?

What is the recommended dose modification for grade 3 diarrhea?