U.S. spent $1.5 billion in 2006 on Vytorin, a cholesterol drug that actually does not work better than an older drug, which is sold for a fifth of Vytorin’s price.

Researchers discovered that the cholesterol pill produced by Schering-Plough Corp. and Merck & Co., which was prescribed 20 million times last year, actually did not slow the clogging of arteries better than Merck’s Zocor, which is much cheaper.

The researchers, led by Cynthia Jackevicius of the Western University of Health Sciences in Pomona, California, analyzed the effectiveness of ezetimibe, an ingredient that was combined with statin to form Vytorin. Statins are a class of drug that reduce the amount of cholesterol produced in the body, and protect people from heart disease.

Since ezetimibe was combined with statins in July 2004, a large advertising campaign started, which led to an increased number of prescriptions of Vytorin in the US.

But manufacturers Merck and Schering-Plough announced that the combination did not have results as good as the treatment with statin alone.

The advertising campaign for Vytorin was stopped and a US congressional committee is currently investigating whether the two companies were aware of the results for a long time before admitting the drug was ineffective.

The discovery was presented at the American College of Cardiology in Chicago on Sunday, and the top U.S. heart doctors advised patients to use the older cholesterol drugs instead of Vytorin, which is less effective.

“This study provides no new evidence to support the use of this drug, and it moves us to more uncertainty about the benefits,'' said Harlan Krumholz, a cardiologist at Yale University, according to Bloomberg.com. “You've just seen a clinical trial that should change practice.”