About 20 percent of kidney dialysis patients who undergo a procedure to open a blocked artery are given the wrong blood clot medicine, increasing the chances of significant bleeding, researchers said Tuesday.

They said the findings suggest many doctors in the United States ignore warnings on drug labels, often putting patients at risk of serious harm or death.

The results of this study illustrate the problem of medication errors in the United States, as well as the need to make patient safety a priority on the health care agenda, Dr. Thomas Tsai of the Denver Veterans Affairs Medical Center and colleagues wrote in the Journal of the American Medical Association.

In the United States, medication errors cause more than 100,000 deaths each year, usually from drugs that are prescribed or given to patients who could be harmed by them.

Tsai and colleagues studied the use of two blood thinners -- Lovenox, also known as enoxaparin, made by Sanofi-Aventis SA's and Merck Schering-Plough's Integrilin, also known as eptifibatide.

Both drugs are not recommended for use in kidney dialysis patients, who are at particular risk of dangerous reactions because the blood thinners are cleared from the body through the kidneys.

The researchers used data from 829 U.S. hospitals on 22,778 dialysis patients between January 2004 and August 2008 who underwent percutaneous coronary intervention -- a procedure in which a tube is inserted into an artery to open a blockage.

They found that overall, 5,084 patients or 22.3 percent, got a blood thinner that was not recommended for them, and these patients had nearly twice the number of major bleeding events in the hospital and significantly more deaths.

This study therefore demonstrates that these medications are used in clinical practice despite (U.S. Food and Drug Administration) FDA-directed labeling, and their use is associated with adverse patient outcomes, the team wrote.

They recommended educational programs targeting doctors who prescribe these drugs and other measures to protect the safety of patients with compromised kidney function.

Medicine