Negative side effects of iron for people with kidney disease

Aug 2 2004

More than 20 million Americans– one in nine adults– have chronic kidney disease, and most don't even know it.

Physicians are constantly searching for the most effective therapies to help people with end-stage renal disease (ESRD), which occurs when kidney disease has progressed and about 90% of kidney function has been lost. While iron therapy is a common treatment for such patients, new evidence suggests that iron is potentially toxic and its long-term consequences are unknown. Given that intravenous iron can damage normal kidneys, its potential toxicity might be even greater in kidneys affected by disease.

The journal Kidney International, published by Blackwell on behalf of the International Society of Nephrology, just released findings from an experimental study revealing that intravenous iron therapy administered to patients with kidney disease may have negative side effects. More clinical studies need to be performed to corroborate the findings.

Dr. Richard Allen Zager, a prominent researcher who has served as a NIH funded investigator on kidney disease for the past 25 years, noted "This study will likely stimulate aggressive clinical investigation of the issues raised by the findings of this experimental paper." The study provides support for the concept that parenteral iron formulations are potentially toxic. Rather than helping patients, iron therapy may exacerbate progressive renal damage. Yet iron therapy remains essential in the treatment of patients with chronic kidney disease.

This study points out that the level of toxicity depends on the nature of the iron formula given to patients. The four types of formulations–iron dextran (INFeD from Watson Pharmaceuticals), iron sucrose (Venofer from American Regent), iron gloconate (Ferrlecit from Watson Pharmaceutics) and Feoligosaccharide (FeOS, currently in clinical trials from Pharmacosmos) – are statistically different in their toxicity in this study. In highlighting the differences in toxicity among currently used iron replacement therapies, this study could ultimately impact drug selection by physicians.