Plavix is the second most commonly prescribed medication.  It is used to decrease platelet stickiness to prevent heart attacks, strokes, and stent occlusions.  However, according to the FDA's mandated "black box" warning on the Plavix label, over 30% of takers are poorly responsive to the drug and are left unprotected.  Ten to fifteen percent of aspirin takers are also non-responsive to their aspirin.  Shouldn't you know if these critical drugs are working?