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Elemental Iron Side Effects

Generic Name: carbonyl iron

Note: This document contains side effect information about carbonyl iron. Some of the dosage forms listed on this page may not apply to the brand name Elemental Iron.

For the Consumer

Applies to carbonyl iron: oral suspension

What are some side effects that I need to call my doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your child's doctor or get medical help right away if your child has any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Black, tarry, or bloody stools.
  • Fever.
  • Very upset stomach or throwing up.
  • Very bad belly pain.
  • Throwing up blood or throw up that looks like coffee grounds.

What are some other side effects of this drug?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your child's doctor or get medical help if your child has any side effects that bother your child or do not go away.

  • Belly pain.
  • Upset stomach or throwing up.
  • Loose stools (diarrhea).
  • Hard stools (constipation).
  • Change in color of stool to green.
  • Not hungry.
  • Stomach cramps.
  • Staining of the mouth, teeth, or fillings.

These are not all of the side effects that may occur. If you have questions about side effects, call your child's doctor. Call your child's doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects at

For Healthcare Professionals

Applies to carbonyl iron: oral suspension, oral tablet, oral tablet chewable


Gastrointestinal side effects have been reported the most frequently. They have included diarrhea (45%) vs. placebo (3%), cramping (38%) vs. placebo (0%), nausea (30%) vs. placebo (8%), constipation (25%) vs. placebo (14%), heartburn (17%) vs. placebo (6%), and epigastric discomfort (16%) vs. placebo (11%).[Ref]

Constipation may be relieved by administering docusate sodium 100 mg to 200 mg per day in addition to increasing the intake of oral fluids, such as water.[Ref]


Iron overload (i.e., hemosiderosis) has been reported in patients genetically predisposed, or have underlying disorders, that augment the absorption of iron. It has also occurred following administration of excessive parenteral iron therapy, combination of oral and parenteral iron, or in patients with hemoglobinopathies that were erroneously diagnosed as iron deficiency anemia. Hemosiderosis is treated with repeated phlebotomy or long-term administration of deferoxamine. The liver is particularly susceptible to toxicity in iron-overload states.

Stained teeth have been reported primarily following ingestion of iron liquid preparations. Liquid dosage forms should be diluted in juice or water and sipped through a straw to aid in prevention of staining.[Ref]

Other side effects have included iron overload (hemosiderosis) and stained teeth. Secondary hemochromatosis due to prolonged iron ingestion has been reported rarely. An unpleasant taste following carbonyl iron ingestion has been reported in 40% to 70% of patients.[Ref]

Nervous system

Nervous system side effects have included headache (29%) vs. placebo (25%), and weakness (11%) vs placebo (9%).[Ref]


1. "Product Information. Feosol Caplets (carbonyl iron)" SmithKline Beecham, Philadelphia, PA.

2. Gordeuk VR, Brittenham GM, Hughes M, Keating LJ, Opplt JJ "High-dose carbonyl iron for iron deficiency anemia: a randomized double-blind trial." Am J Clin Nutr 46 (1987): 1029-34

3. Devasthali SD, Gordeuk VR, Brittenham GM, Bravo JR, Hughes MA, Keating LJ "Bioavailability of carbonyl iron: a randomized, double-blind study." Eur J Haematol 46 (1991): 272-8

4. Gordeuk VR, Brittenham GM, McLaren CE, Hughes MA, Keating LJ "Carbonyl iron therapy for iron deficiency anemia." Blood 67 (1986): 745-52

5. Gordeuk VR, Brittenham GM, Hughes MA, Keating LJ "Carbonyl iron for short-term supplementation in female blood donors." Transfusion 27 (1987): 80-5

Some side effects of Elemental Iron may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

More about Elemental Iron (carbonyl iron)

Consumer resources

Other brands: Iron Chews, Feosol Natural Release, Icar, Wee Care

Professional resources

Related treatment guides

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.