DPYD genotyping and predicting fluoropyrimidine toxicity: where do we stand?

Pharmacogenomics. 2023 Jan;24(2):93-106. doi: 10.2217/pgs-2022-0135. Epub 2023 Jan 13.


Fluoropyrimidines (FPs) are antineoplastic drugs widely used in the treatment of various solid tumors. Nearly 30% of patients treated with FP chemotherapy experience severe FP-related toxicity, and in some cases, toxicity can be fatal. Patients with reduced activity of DPD, the main enzyme responsible for the breakdown of FP, are at an increased risk of experiencing severe FP-related toxicity. While European regulatory agencies and clinical societies recommend pre-treatment DPD deficiency screening for patients starting treatment with FPs, this is not the case with American ones. Pharmacogenomic guidelines issued by several pharmacogenetic organizations worldwide recommend testing four DPD gene (DPYD) risk variants, but these can predict only a proportion of toxicity cases. New evidence on additional common DPYD polymorphisms, as well as identification and functional characterization of rare DPYD variants, could partially address the missing heritability of DPD deficiency and FP-related toxicity.

Keywords: DPYD; adverse drug reactions; chemotherapy; dihydropyrimidine dehydrogenase; fluoropyrimidine toxicity; fluoropyrimidines; fluorouracil; pharmacogenetics.

Publication types

  • Review

MeSH terms

  • Antimetabolites, Antineoplastic* / adverse effects
  • Antimetabolites, Antineoplastic* / toxicity
  • Capecitabine / adverse effects
  • Dihydropyrimidine Dehydrogenase Deficiency* / genetics
  • Dihydrouracil Dehydrogenase (NADP)* / genetics
  • Fluorouracil* / adverse effects
  • Fluorouracil* / toxicity
  • Genotype
  • Humans
  • Pharmacogenomic Variants*


  • Antimetabolites, Antineoplastic
  • Capecitabine
  • Dihydrouracil Dehydrogenase (NADP)
  • Fluorouracil