What is the danger of taking iron over a extended period of time?

  • Q: What is the danger of taking iron over a extended period of time? This 82 year old has a history of colon cancer and has just had another polyp removed, which came back malignant.
  • A: Supplemental iron is available in two forms: ferrous and ferric. Ferrous iron salts (ferrous fumarate, ferrous sulfate, and ferrous gluconate) are the best absorbed forms of iron supplements. Elemental iron is the amount of iron in a supplement that is available for absorption. The amount of iron absorbed decreases as more iron is consumed in one dose. It is better to separate iron doses over 2-3 equally spaced doses. Iron may cause gastrointestinal side effects such as nausea, vomiting, constipation, diarrhea, dark colored stools, and/or abdominal distress. Constipation in elderly can especially be uncomfortable. Little iron is excreted from the body. Thus, iron can accumulate in body tissues and organs when normal storage sites are full. However, this is unusual unless the individual has an abnormality that causes them to absorb iron too efficiently. It is usually okay for an individual to continue taking iron if they are anemic. It is not uncommon for cancer patients to become anemic and need to supplement with iron. Given the past history of colon cancer, it would probably be in the best interest for the physician to determine if iron should be continued or stopped. The physician hopefully has current lab results and can make an educated decision based on the labs and past history. Kimberly Hotz, PharmD
This question was answered on July 23, 2010.


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