Friday, August 7, 2009

iv iron preparations

Because of the generally poor GI absorption of iron in the setting of ESRD, iron supplementation in dialysis patients is now carried out by intravenous formulations of iron complexed to various carbohydrates. The idea is that these carbohydrate moieties can function as "molecular shields", allowing for the safe delivery of iron to its target tisues while simultaneously preventing iron-mediated oxidative damage. Here are some of the main iv iron formulations and their unique attributes:

1. iron gluconate (Ferrlicit). In my limited experience, it appears to me that Ferrlicit and Venofer control the lion's share of iv iron formulations in U.S. dialysis centers. A typical course of Ferrlicit typically given in the ESRD patient is 125mg iv qdialysis session x 8 doses.

2. iron sucrose (Venofer). Also a popular option, the typical dosing for Venofer is 100mg iv qdialysis x 10 doses. Both Venofer and Ferrlicit offer fairly rapid release of iron. Also, Venofer is FDA-approved for iron repletion in non-dialysis-dependent CKD patients whereas Ferrlicit is not.

3. iron dextran (Dexferrum, Imferon): this is not used much anymore because of a significantly higher risk of anaphylactic reactions than the more modern Ferrlicit and Venofer. Iron dextran was typically given as a smaller "test dose" prior to giving the full dose, as a precaution against anaphylaxis.

4. low-molecular weight iron dextran (CosmoFer, InFed): it is important to distinguish low-molecular weight dextran from high molecular weight dextran because its risk of adverse events is so much lower.

5. ferumoxytol (Feraheme): this is a newly-released formulation of "iron oxide nanoparticles." Sounds very space-age, doesn't it? The reported advantage is that it can be given in large bolus doses--thus making it preferable for the treatment of iron deficiency in CKD, where a patient would otherwise be required to make multiple trips to an infusion center to get their Venofer or Ferrlicit. Further assessments of safety and efficacy are still needed.


Nishant said...

One of the biggest disadvantages of using ferumoxytol (Feraheme) is that it is fero-magnetic. So u cannot do MRI for 3 months on your patients or else it would give false positive results. There is an ongoing study to use this as an contrast material for MRI!!

Ous ESRD patients tend to get CT/MRI more frequently than other patient population.

nathanhellman said...

Thanks for your comments--I have never used ferumoxytol so I am not as familiar with it as compared to Venofer and Ferrlicit. For dialysis patients the MRI issue may not be such a big one however as they are presently being guided away from MRI, based on the perceived risk for nephrogenic systemic fibrosis.