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Tandem F Side Effects

Generic Name: ferrous fumarate / folic acid / iron polysaccharide

Note: This document contains side effect information about ferrous fumarate / folic acid / iron polysaccharide. Some of the dosage forms listed on this page may not apply to the brand name Tandem F.

For the Consumer

Applies to ferrous fumarate / folic acid / iron polysaccharide: oral capsule

Get emergency medical help if you have any of these signs of an allergic reaction while taking ferrous fumarate/folic acid/iron polysaccharide: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Common side effects may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

For Healthcare Professionals

Applies to ferrous fumarate/folic acid/iron polysaccharide: oral capsule


Hypersensitivity side effects associated with folic acid have been reported rarely. They have included erythema, rash, pruritus, malaise, dyspnea with bronchospasm, and a single case of apparent anaphylaxis.[Ref]


Gastrointestinal side effects associated with ferrous fumarate have included anorexia, nausea, diarrhea, constipation, heartburn, vomiting, and discoloration of stools.[Ref]

Cases of gastrointestinal discomfort are typically mild and subside with continuation of therapy. According to the manufacturer, ferrous fumarate-folic acid-iron polysaccharide is best absorbed when administered at bedtime; however, gastrointestinal side effects in may be minimized when administered with a meal.

Constipation may be relieved by increased fiber in the diet.

Discoloration of stools is a harmless effect resulting from unabsorbed iron.[Ref]


Immunologic side effects associated with oral iron products have rarely included gastroenteritis associated with Yersinia enterocolitica and Listeria monocytogenes in patients with iron overload status receiving treatment with deferoxamine.[Ref]

It has been hypothesized that gastroenteritis is caused by bacteria that become virulent in the presence of iron overload resulting in a systemic infection. Treatment consists of discontinuing deferoxamine and initiating appropriate antimicrobial therapy.[Ref]


Other side effects have included iron overload (hemosiderosis). Secondary hemochromatosis due to prolonged iron ingestion has been reported rarely.[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.[Ref]

Nervous system

Nervous system side effects have been reported in some patients receiving folic acid in daily dosages of 15 mg.

Daily doses of folic acid greater than 100 mcg can obscure pernicious anemia in that hematologic remission can occur while neurologic signs and symptoms progress.[Ref]

Nervous system side effects associated with folic acid have included sleep disturbances, concentration problems, irritability, anxiety, depression, confusion, and impaired judgment.[Ref]


1. "Product Information. Tandem F (ferrous fumarate/FA/iron polysaccharide)." US Pharmaceutical Corporation, Decatur, GA.

Some side effects of Tandem F 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 Tandem F (ferrous fumarate / folic acid / iron polysaccharide)

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