DPYD

Drugs affected by DPYD

Dihydropyrimidine Dehydrogenase

2 medications 5 brand products

About DPYD

DPYD breaks down fluoropyrimidine chemotherapy drugs (5-FU, capecitabine).^[1] A small percentage of people carry reduced-function variants that cause the drug to accumulate to toxic levels. This is one of the few pharmacogenetic tests that is mandatory in many oncology guidelines before starting treatment.^[2]

Partial DPYD deficiency calls for a 25 to 50 percent dose reduction. Complete deficiency is a contraindication: standard-dose fluoropyrimidine can be fatal.^[3]

What we test for DPYD

Gene2Rx reports your DPYD genotype across 28 named alleles, built from 28 variants curated by PharmVar.

Named alleles

Variants tested

PharmVar

Source

GRCh38

Genome build

Normal Function 1 Decreased Function 6 No Function 21

Notable DPYD alleles

Reference Normal Function

No tested DPYD variants — typical DPD enzyme activity expected.

c.1905&1G>A No Function

A no-function splice-site variant strongly associated with fluoropyrimidine toxicity.

~1% in Europeans

c.1679T>G No Function

A no-function variant (also called *13) linked to severe fluoropyrimidine adverse events.

c.2846A>T Decreased Function

A decreased-function missense variant; carriers warrant a fluoropyrimidine dose reduction.

What do these allele names mean?

DPYD alleles are named by the underlying DNA variant rather than a star number — for example c.61C>T describes a single base change at position 61 of the coding sequence.

You inherit one allele from each parent, and the pair determines whether your DPYD activity is normal, decreased, or absent.

PharmVar is the international registry that curates these names. Gene2Rx tests every variant needed to call each cataloged DPYD allele.

View the full DPYD allele catalog on PharmVar →

Medications with DPYD guidelines

Gene2Rx covers 2 medications with published pharmacogenetic guidance for DPYD, drawn from CPIC and FDA sources. Each drug links to its full pharmacogenetics page.

chemotherapies →

Capecitabine CPIC / FDA Fluorouracil CPIC / FDA

Brand products containing a DPYD-affected ingredient

These branded medications include at least one active ingredient whose metabolism or action involves DPYD. Each links to its full pharmacogenetic breakdown.

References

CPIC. CPIC Guideline for Fluoropyrimidines and DPYD (2017). cpicpgx.org
U.S. Food and Drug Administration. Table of Pharmacogenomic Biomarkers in Drug Labeling (2024). fda.gov
PharmGKB / Stanford University. PharmGKB: The Pharmacogenomics Knowledge Base. pharmgkb.org

Find out your personal DPYD phenotype

This page lists drugs affected by DPYD. A Gene2Rx report tells you which metabolizer group you fall into, and what that means for every medication on this list.

Get your report Look up a medication

Informational only, not medical advice. The presence of a DPYD pharmacogenetic guideline does not mean every patient needs to change their dose. Never start, stop, or change a medication without talking to your prescribing clinician.