Is Kapetral affected by genetics?

Yes — the active ingredient is metabolized by a gene known to vary between individuals.

Relevant genes: DPYD

Kapetral is affected by pharmacogenetics through the DPYD gene. Your genotype for this gene can change how your body processes Kapetral, which can affect both how well it works and how well you tolerate it. The strongest evidence level on this page is Strong, based on CPIC or FDA guidelines.

What's in Kapetral

capecitabine affected by DPYD

Affected by DPYD · CPIC, FDA · Strong evidence

Read the full capecitabine genetics guide →

Capecitabine phenotype recommendations

Published guidance from CPIC and FDA on how capecitabine should be dosed or substituted based on your DPYD phenotype.

Phenotype	What it means	Recommendation	Evidence
Normal Metabolizer DPYD	Your body processes capecitabine normally. You have a typical risk of side effects, and the standard dose is expected to be appropriate.	CPIC Based on genotype, there is no indication to change dose or therapy. Use label-recommended dosage and administration FDA Initiate therapy with recommended starting dose.	Strong
Intermediate Metabolizer DPYD	Your body processes capecitabine more slowly than normal, which increases the risk of severe side effects. Your doctor will likely start you on a lower dose and adjust based on how you respond.	CPIC + CPIC Reduce starting dose by 50% followed by titration of dose based on toxicity or therapeutic drug monitoring (if available). Patients with the c.[2846A>T];[2846A>T] genotype may require >50% reduction in starting dose. FDA Insufficient data to recommend a specific dosage. Withhold or discontinue in the presence of early-onset or unusually severe toxicity. Refer to FDA labeling for specific recommendations.	Strong
Poor Metabolizer DPYD	Your body has very limited ability to process capecitabine, putting you at high risk for severe or life-threatening side effects. Your doctor may avoid this drug or use a much lower dose with close monitoring.	CPIC + CPIC Activity score 0.5: Avoid use of 5- fluorouracil or 5-fluorouracil prodrug-based regimens. In the event, based on clinical advice, alternative agents are not considered a suitable therapeutic option, 5-fluorouracil should be administered at a strongly reduced dose with early therapeutic drug monitoring.l Activity score 0: Avoid use of 5-fluorouracil or 5-fluorouracil prodrug-based regimens. FDA Avoid capecitabine. No dosage has proven safe in poor metabolizers. Consider an alternative treatment.	Strong
Indeterminate DPYD	The impact of your genotype on response to this drug is unknown	CPIC + FDA Initiate therapy with recommended starting dose.	—
Not available DPYD	The impact of your genotype on response to this drug is unknown	CPIC + FDA Initiate therapy with recommended starting dose.	—

Sources: CPIC, FDA

The gene behind the guidance

DPYD Dihydropyrimidine Dehydrogenase

DPYD breaks down fluoropyrimidine chemotherapy drugs (5-FU, capecitabine). 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.

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

See all drugs affected by DPYD →

Browse the full drug-class: Chemotherapy agents.

Related medications

Find out how your genetics affect Kapetral

This page describes the general pharmacogenetics. A Gene2Rx report analyzes your own DNA to tell you which metabolizer group you fall into, across every medication.

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Informational only — not medical advice. Pharmacogenetic guidance describes population-level patterns; your individual response depends on many factors. Never start, stop, or change a medication without talking to your prescribing clinician.