The study, which started in July 2007, relied upon Medco's integrated medical and pharmacy claims systems and included patients aged 40-75 who were initiating warfarin therapy anywhere in the country for any reason and prescribed by any physician.  The average age of the patients in the study was 65 and males represented about 60 percent of both the study and control groups.   DNA samples obtained from either blood cells or buccal cells (cotton swab scraped inside the cheek) were analyzed by Mayo Clinic to supply physicians with genetic information pertaining to the CYP2C9 and VKORC1 genes which affect patient response to the drug.  Mayo Clinic reports provided doctors with information on how to interpret the results and apply them to drug management decisions.  Medical claims were used to compare hospitalization rates between the group receiving the genetic test and those who did not.

Warfarin: Old drug with genetic link

Warfarin, which is sold by generic drug manufacturers and distributors, and under the brand name Coumadin by Bristol Myers Squibb and under the brand name Jantoven?® by Upsher-Smith, is used to reduce the risk of death, heart attack or stroke after a patient has a heart attack.  It is also used to treat and prevent venous thrombosis (blood clots), pulmonary embolism, and thromboembolism associated with atrial fibrillation or heart valve replacement surgery.  The drug has been available as a medication for more than 50 years, but warfarin therapy requires regular patient monitoring because of its narrow therapeutic range, meaning that the dose needed to obtain a therapeutic effect is very close to the dose that can cause serious adverse events.  Genetic testing offers an additional opportunity to help clinicians reach a more precise dose for patients.  

SOURCE Medco Health Solutions, Inc.