(August 25, 2009 - Insidermedicine) Some of the genetics underlying why certain individuals have a stronger reaction to the blood thinning drug clopidogrel have been revealed in a study published in the Journal of the American Medical Association.

Here is some information about clopidogrel:

•    It is an antiplatelet drug, which prevents the blood from clotting

•    It is prescribed to prevent heart attacks and strokes caused by blood clots in certain high risk individuals

•    To be effective, it must be taken every day

Researchers from the University of Maryland conducted genetic testing to determine which genes are likely to be involved in differing responses to clopidogrel. They also administered the drug to over 400 genetically similar Amish people. Finally, they looked at whether certain genes could affect long-term outcomes in over 200 individuals receiving clopidogrel following an invasive cardiac procedure.

A gene variant was found to be responsible for 12% of the variation in the response to clopidogrel. Among patients who underwent the cardiac procedure, carriers of the gene were twice as likely to die or have a blood clot-related cardiac event during the following year than non-carriers.

Today's research demonstrates how genetic testing can be used to tailor drug treatment.

For Insidermedicine in Depth, I'm Dr. Kelly Schweitzer.