Genetic test to help prescribe proper dose of blood-thinner warfarin

Patients suffering from dangerous blood clots will receive genetic testing to help health professionals at the University of Illinois Hospital & Health Sciences System prescribe the proper dose of the blood-thinner warfarin.

The UI Health System is one of the first in the nation to use genetic information to help patients receive the right dose of the drug, which consistently ranks among the leading causes of serious drug-related adverse events.

The genetic test will identify common variants in CYP2C9, an enzyme that breaks down warfarin, and VKORC1, a clotting enzyme that is the target of warfarin, says Larisa Cavallari, UIC associate professor of pharmacy practice and one of the co-directors of the new program.

The ultimate goal, Cavallari said, is to provide personalized medicine to patients, customized to account for their unique genetic ancestry.

"The majority of pharmacogenetic research and use of pharmacogenetics in clinical practice in the United States has been in populations of European descent," says Edith Nutescu, UIC clinical professor of pharmacy practice and co-director of the program. "We're confident that genotype-guided pharmacotherapy in urban, underserved populations will improve the effectiveness and safety of medications."

Warfarin is difficult to dose, and is usually begun at similar amounts for all patients, Cavallari said. It It is prescribed to treat deep vein thrombosis and pulmonary embolism and to prevent stroke as a result of atrial fibrillation or heart valve replacement. It carries a "black-box" warning from the Food and Drug Administration for bleeding risk.