On August 16, the The FDA approved new labeling information for the blood-thinner  warfarin, sold under the brand name Coumadin. The new label suggests that one  can prescribe higher or lower doses that may be safer for patients with variations  in two genes, CYP2C9 or VKORC1. These variations can be learned through  genetic testing, which may be a useful tool in determining appropriate dosing  levels for individual patients with lower risks of bleeding complications.  

“The FDA labeling change for warfarin is the next step in the pathway toward  incorporating genetics into the care of patients who need anticoagulation,” said Marc S. Williams, MD,  FACMG, ACMG board member and a cochair of the expert group on  Pharmacogenetic Testing of CYP2C9 and VKORC1 Alleles for Warfarin Use. “The  FDA has said that physicians should be aware of the role of genetics in warfarin  dosing, but now the hard part is doing the necessary groundwork to determine  how best to use genetic testing to improve care.”

This group is completing a report on the use of pharmacogenetic testing for  warfarin and is based on a rapid-ACCE (analytic validity, clinical validity,  clinical utility and ethical, legal and social implications) Review on Genetic  Testing and Warfarin Dosing.