Dialysis Patients Given Dangerous Drugs

This is an expansion of a news item summary. It discusses a report in the Journal of the American Medical Association - Tsai T, et al "Contraindicated medication use in dialysis patients undergoing percutaneous coronary intervention" JAMA 2009; 302: 2458- 64.

When on dialysis, it is part of the duty of any doctor treating you for some other problem to ensure that the treatment they use does not conflict with the dialysis. It seems only natural to check that any drugs used do not have unfortunate side effects for dialysis patients, doesn't it? However a study showed that in some cases the exact opposite seems to have occured. Their report says that it seems as if many doctors in the United States ignore the warnings on drug labels, which can put patients at risk.

The treatment under study was percutaneous coronary intervention (angioplasty), intended to open a blocked artery. It was found that around 20% of kidney dialysis patients who were undergoing this operation were given blood "thinners" that increased their chances of having problems involving considerable bleeding during the procedure, with an associated increased probability of dying (6.5% of those treated died). The research examined two commonly used drugs - Sanofi-Aventis’ Lovenox (Enoxaparin) and Merck Schering-Plough’s Integrilin (Eptifibatide). Both of these drugs are specifically recommended as not suitable for dialysis patients. Bleeding most commonly occurred in the gastrointestinal tract (usually it's the entry wound that would bleed in the absence of these drugs). As these drug are renally cleared from the body, someone with kidney failure would not remove them from their system as readily as a patient with fully functional kidneys.

It was suggested that one reason these drugs were used is that eptifibatide is less costly and more widely available than abciximab, a preferred alternative.

This was not a small study by any stretch of the imagination (small study groups can give results of little or no statistical importance). The study involved data from 829 hospitals, covering 22,778 dialysis patients. Out of this group they found that 5,084 patients (yes, that's what it says!) were given the wrong blood thinner (anti-clotting agent). That's 22.3%. On a study of this scale that is a very worrying result indeed. It shows the extent to which patients are exposed to medication errors. A tightening up of proceedures is clearly required to ensure patient safety. Especially since the authors of the research note that their results may even underestimate the problem!