Genotypes for Warfarin Sensitivity

Warfarin is used to prevent blood clots from forming or growing larger in your blood and blood vessels. It is prescribed for people with certain types of irregular heartbeat, people with prosthetic heart valves, and people who have suffered a heart attack. Warfarin is also used to treat or prevent venous thrombosis and pulmonary embolism.

Warfarin sensitivity is a condition in which individuals have a low tolerance for the drug warfarin. People with warfarin sensitivity take longer than normal to break down (metabolize) warfarin. The medication remains active in their body longer than usual, so they require lower doses. These individuals are classified as "slow metabolizers" of warfarin. Other people with warfarin sensitivity do not need as much drug to prevent clots because their clot-forming process is naturally slower than average and can be stopped by low warfarin doses. If people with warfarin sensitivity take the average dose (or more) of warfarin, they are at risk of an overdose, which can cause abnormal bleeding in the brain, gastrointestinal tract, or other tissues, and may lead to serious health problems or death

Variations of the CYP2C9 and VKORC1 genes can decrease a persons ability to break down warfarin, which causes the drug's effect to last longer, resulting in the need for lower doses.

Related to:
Coumadin, Jantoven