Are we giving too much iron? Low-dose iron therapy is effective in octogenarians

Am J Med. 2005 Oct;118(10):1142-7. doi: 10.1016/j.amjmed.2005.01.065.


Purpose: Elderly patients are vulnerable to the dose-dependent adverse effects of iron replacement therapy. Our study examines whether low-dose iron therapy can efficiently resolve iron-deficiency anemia in patients over the age of 80 years and reduce adverse effects.

Subjects and methods: Ninety hospitalized patients with iron-deficiency anemia were randomized to receive elemental iron in daily doses of 15 mg or 50 mg as liquid ferrous gluconate or 150 mg of ferrous calcium citrate tablets for 60 days. Thirty control patients without anemia were given 15 mg of iron for 60 days. A 2-hour iron absorption test was performed after the initial dose. Hemoglobin and ferritin levels were measured on day 1, 30, and 60 after initiating therapy. Each patient completed a weekly questionnaire regarding drug-induced adverse effects.

Results: Serum iron rose significantly in the anemic patients beginning 15 minutes after the first dose but not in nonanemic patients. Two months of iron treatment significantly increased hemoglobin and ferritin concentrations similarly in all 3 groups of iron-deficiency anemia patients (for example, hemoglobin levels rose from 10.0 g/dL to 11.3 g/dL with 15 mg/d of iron therapy and from 10.2 g/dL to 11.6 g/dL with 150 mg/d). Abdominal discomfort, nausea, vomiting, changes in bowel movements, and black stools were significantly more common at higher iron doses.

Conclusions: Low-dose iron treatment is effective in elderly patients with iron-deficiency anemia. It can replace the commonly used higher doses and can significantly reduce adverse effects.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Aged, 80 and over
  • Anemia, Iron-Deficiency / drug therapy*
  • Antioxidants / administration & dosage*
  • Antioxidants / adverse effects
  • Antioxidants / pharmacokinetics
  • Calcium Citrate / administration & dosage*
  • Calcium Citrate / adverse effects
  • Calcium Citrate / pharmacokinetics
  • Dose-Response Relationship, Drug
  • Female
  • Ferritins / blood
  • Ferrous Compounds / administration & dosage*
  • Ferrous Compounds / adverse effects
  • Ferrous Compounds / pharmacokinetics
  • Hemoglobins / analysis
  • Humans
  • Iron / blood
  • Male
  • Reticulocyte Count


  • Antioxidants
  • Ferrous Compounds
  • Hemoglobins
  • Ferritins
  • Iron
  • Calcium Citrate
  • ferrous gluconate