Following initiation of oral iron replacement therapy, signs and symptoms of iron deficiency should gradually abate. Patients who do not have resolution of symptoms or expected changes in hemoglobin should be evaluated for the reason(s).

Usual oral dose of iron for replacement: 150 - 200 mg of elemental iron daily


Clinical response:

(1) Constitutional symptoms may improve within the first few days of therapy.

(2) Glossitis and koilonychia may take several months to resolve.


Hemoglobin response:

(1) The hemoglobin may not change during the first week of therapy.

(2) The hemoglobin should increase about 0.2 g/dL after the first week of therapy.

(3) An increase < 0.1 g/dL is a suboptimal response.


Hematologic response:

(1) The reticulocyte response should increase 2-3 times the pretreatment levels.

(2) Microcytosis may take up to 4 months to resolve.


Ferritin response:

(1) The serum ferritin level will remain low until the iron stores are replaced.

(2) Return of serum ferritin to normal levels may take several months of therapy.


Failure of oral therapy: all of the following:

(1) receiving full doses of a conventional form of oral iron

(2) hemoglobin has not normalized within 6 weeks of starting therapy.


Causes for failure to achieve typical response:

(1) lower dose (will take longer to achieve levels)

(2) noncompliance

(3) poor absorption

(4) continued blood loss

To read more or access our algorithms and calculators, please log in or register.