CYP2C9

Gastrointestinal & Hepatic System · Phase I & Phase II Xenobiotic Detoxification

Why does CYP2C9 matter when discussing warfarin?

CYP2C9 helps break down warfarin and several other drugs. A confirmed genotype can contribute to a prescribing assessment, alongside the other genetic and clinical factors that influence response.

Common Gene Name: cytochrome P450 family 2 subfamily C member 9
NCBI Gene ID: 1559
Chromosome: 10

Clinical Evidence Status

Drug-response evidence availableTumor or drug-label biomarker context

These labels describe available evidence about a gene. They do not classify your variant or recommend a treatment.

Answer Sources

Explore supporting evidence (35 records)

Condition or drug	Evidence	Grade / status	Context	Source
Warfarin sensitivity	MedlinePlus related condition	Association type varies; no grade assigned here		View source 2015-06
Celecoxib	FDA pharmacogenetics	Management recommendation	Drug-specific subgroup	View source
Dronabinol	FDA pharmacogenetics	Management recommendation	Drug-specific subgroup	View source
Erdafitinib	FDA pharmacogenetics	Management recommendation	Drug-specific subgroup	View source
Flurbiprofen	FDA pharmacogenetics	Management recommendation	Drug-specific subgroup	View source
Fosphenytoin	FDA pharmacogenetics	Management recommendation	Drug-specific subgroup	View source
Meloxicam	FDA pharmacogenetics	Management recommendation	Drug-specific subgroup	View source
Nateglinide	FDA pharmacogenetics	Management recommendation	Drug-specific subgroup	View source
Phenytoin	FDA pharmacogenetics	Management recommendation	Drug-specific subgroup	View source
Piroxicam	FDA pharmacogenetics	Management recommendation	Drug-specific subgroup	View source
Siponimod	FDA pharmacogenetics	Management recommendation	Drug-specific subgroup	View source
Warfarin	FDA pharmacogenetics	Management recommendation	Drug-specific subgroup	View source
Avatrombopag	FDA pharmacogenetics	Pharmacokinetics only	Drug-specific subgroup	View source
Ibuprofen	FDA pharmacogenetics	Pharmacokinetics only	Drug-specific subgroup	View source
Avatrombopag (6)	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Hematology	View source
Celecoxib	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Rheumatology	View source
Dronabinol	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Gastroenterology	View source
Erdafitinib (2)	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Oncology	View source
Etrasimod	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Gastroenterology	View source
Fosphenytoin (1)	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Neurology	View source
Flibanserin (1)	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Gynecology	View source
Flurbiprofen	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Rheumatology	View source
Lesinurad	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Rheumatology	View source
Meloxicam	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Anesthesiology	View source
Nateglinide	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Endocrinology	View source
Ospemifene (1)	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Gynecology	View source
Phenytoin (1)	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Neurology	View source
Piroxicam	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Rheumatology	View source
Prasugrel (2)	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Cardiology	View source
Rimegepant	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Neurology	View source
Siponimod	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Neurology	View source
Warfarin (1)	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Hematology	View source
Aficamten	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Cardiology	View source
Deuruxolitinib	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Dermatology	View source
Seladelpar	FDA labeling biomarker	Label mentions biomarker; actionability not inferred	Gastroenterology	View source

Source snapshot: 2026-09-09. Consumer text updated: 2026-09-10. Source dates describe the cited records, not a new clinical review.

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