Zetia and Vytorin were initially approved by the FDA in 2002 and 2004, respectively, for their ability to lower the “bad cholesterol” (LDL). The “bad cholesterol” is believed to be responsible for the buildup of plaque on arterial walls that can lead to a stroke or heart attack.
In January 2008, Merck/Schering Plough Pharmaceuticals – the maker of both Zetia and Vytorin – released the results of a study on the effects of the combination of ezetimibe and high-dose simvastatin versus simvastatin alone on the atherosclerotic process in patients with heterozygous familial hypercholesterolemia, called the ENHANCE study.
This study compared 720 patients taking either Vytorin or only Zocor. By using ultrasounds to examine the neck arteries of these patients from both groups, researchers hoped to determine if the combination drug, Vytorin, had lowered the incidence of plaque buildup in their arteries.
The expectation was that those taking Vytorin would be shown to have less plaque on their arterial walls than those who took Zocor alone.
Instead, the conclusions of the study indicated that Vytorin patients had no less plaque in their arteries than those taking only Zocor. In fact, those taking Vytorin actually had slightly more plaque.