Genetic testing may soon aid physicians in determining appropriate doses of warfarin, and the Food and Drug Administration (FDA) has recently approved a new label for the drug that notes a patient's response to warfarin may vary based on his or her genes.
The FDA estimates that each year 2 million US individuals begin taking warfarin to prevent blood clots, myocardial infarctions, and stroke. But it is difficult for physicians to find the optimal dose for each patient because individuals respond differently to the drug. Patients who receive a higher than necessary dose are at risk of life-threatening bleeding; those who take too low a dose risk blood clots.
Kuehn BM. Warfarin Label Update. JAMA. 2007;298(12):1389. doi:10.1001/jama.298.12.1389-b