The United States FDA has added a boxed warning to Plavix, a drug used by patients with cardiovascular disease.
The FDA has stated some patients have an abnormality in liver enzyme CYP2C19, which transforms Plavix into an active form.
According to the FDA 2% to 14% of the population have an issue with the CYP2C19 enzyme, which would negate Plavix´s heart attack, stroke and cardiovascular death-preventing properties.
Quest diagnostics can provide testing for the CYP2C19 enzyme.
Plavix is the second-best-selling drug in the world with $8.6 billion in revenue in 2008, stated by IMS Health.
