Clopidogrel

• You may know this drug as: Plavix®
• Why it's commonly used: Clopidogrel helps prevent blood clots and conditions often linked to them, such as heart attack, stroke, or other problems that occur due to hardening and narrowing of the arteries. Often referred to by its brand name, Plavix®, this drug works by preventing small particles in your blood, called platelets, from forming unwanted clots.
• Effectiveness concerns: Some people find that this drug isn't effective for them.
• What you can do: Knowing your likely level of effectiveness allows you and your doctor to choose the right drugs for you, and opt for alternatives if needed.
• Did you know? Plavix® is one of the world's top-selling drugs -- more than 100 million people have been prescribed it. Yet up to 30 percent of patients treated with Plavix® do not show adequate anti-clotting response.

As a type of medication called a “pro-drug,” Plavix® must be converted to an active drug in the body before it can exert its anti-clotting effects. A protein called CYP2C19 (pronounced “sip-2-C-19”) is primarily responsible for activating the drug when it passes through the liver. Studies have shown that in people with certain genetic variants, about 30 percent less Plavix® reaches the target tissues in the body. In other words, these genetic variants reduce active levels of Plavix®, and therefore its effectiveness. Navigenics tests for two of the most common genetic variants related to this concern.