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Ferrous Sulfate

Medically reviewed on Nov 15, 2018

Pronunciation

(FER us SUL fate)

Index Terms

  • Feosol Original
  • Ferric Sulfate
  • Ferrous Sulphate
  • FeSO4
  • Iron Sulfate
  • Slow FE

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Elixir, Oral:

FeroSul: 220 (44 Fe) MG/5ML (473 mL) [contains alcohol, usp, fd&c yellow #6 (sunset yellow), propylene glycol, saccharin sodium, sodium benzoate; lemon flavor]

Iron Supplement: 220 (44 Fe) MG/5ML (473 mL) [contains fd&c yellow #6 (sunset yellow), sodium benzoate]

Generic: 220 (44 Fe) MG/5ML (5 mL [DSC], 473 mL)

Liquid, Oral:

Generic: 220 (44 Fe) MG/5ML (473 mL)

Solution, Oral:

BProtected Pedia Iron: 75 (15 Fe) MG/ML (50 mL) [alcohol free, gluten free; contains sodium metabisulfite; citrus flavor]

Fer-In-Sol: 75 (15 Fe) MG/ML (50 mL) [contains alcohol, usp, sodium bisulfite]

Fer-Iron: 75 (15 Fe) MG/ML (50 mL [DSC]) [contains sodium metabisulfite; lemon flavor]

Iron Supplement Childrens: 75 (15 Fe) MG/ML (50 mL) [alcohol free, dye free, gluten free, lactose free; contains sodium bisulfite]

Generic: 75 (15 Fe) MG/ML (50 mL)

Syrup, Oral:

Generic: 300 (60 Fe) MG/5ML (5 mL)

Tablet, Oral:

FeroSul: 325 (65 Fe) MG [contains fd&c blue #2 aluminum lake, fd&c red #40 aluminum lake]

FeroSul: 325 (65 Fe) MG [contains fd&c red #40 aluminum lake, fd&c yellow #6 aluminum lake]

Ferro-Bob: 325 (65 Fe) MG [DSC]

Generic: 325 (65 Fe) MG

Tablet, Oral [preservative free]:

FerrouSul: 325 (65 Fe) MG [sodium free, starch free]

Generic: 325 (65 Fe) MG

Tablet Delayed Release, Oral:

Generic: 324 (65 Fe) MG, 325 (65 Fe) MG

Tablet Extended Release, Oral:

Slow Fe: 142 (45 Fe) MG [contains fd&c blue #1 aluminum lake, fd&c red #40 aluminum lake, fd&c yellow #6 aluminum lake]

Tablet Extended Release, Oral [preservative free]:

Slow Iron: 160 (50 Fe) MG [gluten free]

Generic: 140 (45 Fe) MG

Brand Names: U.S.

  • BProtected Pedia Iron [OTC]
  • Fer-In-Sol [OTC]
  • Fer-Iron [OTC] [DSC]
  • FeroSul [OTC]
  • Ferro-Bob [OTC] [DSC]
  • FerrouSul [OTC]
  • Iron Supplement Childrens [OTC]
  • Iron Supplement [OTC]
  • Slow Fe [OTC]
  • Slow Iron [OTC]

Pharmacologic Category

  • Iron Salt

Pharmacology

Replaces iron, found in hemoglobin, myoglobin, and other enzymes; allows the transportation of oxygen via hemoglobin

Absorption

Iron is absorbed in the duodenum and upper jejunum; in persons with normal serum iron stores, 10% of an oral dose is absorbed; this is increased to 20% to 30% in persons with inadequate iron stores. Food and achlorhydria will decrease absorption

Excretion

Urine, sweat, sloughing of the intestinal mucosa, and menses

Onset of Action

Hematologic response: Oral: ~3 to 10 days

Peak effect: Reticulocytosis: 5 to 10 days; hemoglobin increases within 2 to 4 weeks

Protein Binding

To transferrin

Use: Labeled Indications

Iron-deficiency anemia: Prevention and treatment of iron-deficiency anemias

Off Label Uses

Restless legs syndrome

Iron supplementation has been proposed as therapy for patients with restless legs syndrome (RLS) associated with low ferritin levels and is likely ineffective for other forms of RLS. Results are inconsistent among various forms of iron. Small controlled trials with oral ferrous sulfate have demonstrated varying effects.[Davis 2000], [Wang 2009] American Academy of Sleep Medicine guidelines give iron supplementation an option strength recommendation for use in adults with RLS associated with low ferritin levels based on very low–level supportive evidence; American Academy of Neurology guidelines also recommend that ferrous sulfate be considered in patients with low ferritin levels.[AAN [Winkelman 2016]], [AASM [Aurora 2012]] European Federation of Neurological Societies/European Neurological Society/European Sleep Research Society guidelines consider ferrous sulfate probably effective for the short-term treatment of primary RLS based on limited data.[EFNS/ENS/ESRS [Garcia-Borreguero 2012]]

Contraindications

Hypersensitivity to iron salts or any component of the formulation; hemochromatosis, hemolytic anemia

Dosing: Adult

Note: Multiple concentrations of ferrous sulfate oral liquid exist; close attention must be paid to the concentration when ordering and administering ferrous sulfate; incorrect selection or substitution of one ferrous sulfate liquid for another without proper dosage volume adjustment may result in serious over- or underdosing. Immediate release oral iron products are preferred for treatment of iron deficiency anemia; enteric coated and slow/sustained release preparations are not desired due to poor absorption (Hershko 2014; Liu 2012). Dose expressed in terms of elemental iron; ferrous sulfate contains ~20% elemental iron; ferrous sulfate exsiccated (dried) contains ~30% elemental iron.

Iron deficiency anemia, prevention in areas where anemia prevalence is ≥40% (off-label): Oral: Menstruating women (non-pregnant females of reproductive potential): 30 to 60 mg daily for 3 consecutive months in a year (WHO 2016a)

Iron deficiency anemia, treatment of iron deficiency: Oral: 100 to 200 mg daily in 2 to 3 divided doses (Liu 2012; Stoltzfus 1998; WHO 2001). Note: Extended release tablets are intended for once daily use.

Restless legs syndrome (off-label use): Oral: 65 mg (325 mg ferrous sulfate) twice daily in combination with vitamin C in patients with a ferritin level ≤75 mcg/L (AAN [Winkelman 2016])

Dosing: Geriatric

Lower doses (15 to 50 mg elemental iron/day) may have similar efficacy and less GI adverse events (eg, nausea, constipation) as compared to higher doses (eg, 150 mg elemental iron/day) (Rimon 2005).

Dosing: Pediatric

Note: Multiple concentrations of ferrous sulfate oral liquid exist; close attention must be paid to the concentration when ordering and administering ferrous sulfate; incorrect selection or substitution of one ferrous sulfate liquid for another without proper dosage volume adjustment may result in serious over- or underdosing. Dosage expressed in terms of elemental iron; ferrous sulfate contains ~20% elemental iron; ferrous sulfate exsiccated (dried) contains ~30% elemental iron:

Iron deficiency anemia, prevention: Oral:

Infants ≥4 months (receiving human milk as only nutritional source or >50% as source of nutrition without iron fortified food): 1 mg/kg/day (Baker 2010); Note: In healthy, term infants, AAP does not recommend routine additional supplementation of iron be considered until at least 4 to 6 months if breastfed (full or partial) (Baker 2010; Schanler 2011).

Iron deficiency anemia, prevention in areas where anemia prevalence is ≥40% (off-label; WHO 2016b): Oral: Note: In malaria-endemic areas, iron supplementation in infants and children should be done in conjunction with public health measures to prevent, diagnose and treat malaria.

Infants ≥6 months to Children <2 years: 10 to 12.5 mg daily for 3 consecutive months in a year

Children 2 years to <5 years: 30 mg daily for 3 consecutive months in a year

Children 5 to 12 years: 30 to 60 mg daily for 3 consecutive months in a year

Adolescent menstruating females (non-pregnant females of reproductive potential): 30 to 60 mg daily for 3 consecutive months in a year

Iron deficiency anemia, treatment of iron deficiency: Oral: 3 to 6 mg/kg/day in 3 divided doses (Carney 2010, Kliegman 2011).

Administration

Oral: Do not chew or crush extended-release preparations; administer with water or juice on an empty stomach.

Dietary Considerations

May be administered with food to prevent irritation; however, not with cereals, dietary fiber, tea, coffee, eggs, or milk.

Ferrous sulfate contains ~20% elemental iron (ie, 325 mg ferrous sulfate is equivalent to 65 mg elemental iron); ferrous sulfate exsiccated (dried) contains ~30% elemental iron.

Dietary sources of iron include beans, cereal (enriched), clams, beef, lentils, liver, oysters, shrimp, and turkey. Foods that enhance dietary absorption of iron include broccoli, grapefruit, orange juice, peppers, and strawberries. Foods that decrease dietary absorption of iron include coffee, dairy products, soy products, spinach, and tea.

Dietary reference intake (IOM 2001): Note: Dosage expressed in terms of elemental iron; ferrous sulfate contains ~20% elemental iron; ferrous sulfate exsiccated (dried) contains ~30% elemental iron.

0 to 6 months: 0.27 mg daily (adequate intake)

7 to 12 months: 11 mg daily

1 to 3 years: 7 mg daily

4 to 8 years: 10 mg daily

9 to 13 years: 8 mg daily

14 to 18 years: Males: 11 mg daily; Females: 15 mg daily; Pregnant females: 27 mg daily; Lactating females: 10 mg daily

19 to 50 years: Males: 8 mg daily; Females: 18 mg daily; Pregnant females: 27 mg daily; Lactating females: 9 mg daily

≥50 years: 8 mg daily

Storage

Iron is a leading cause of fatal poisoning in children. Store out of children's reach and in child-resistant containers.

Drug Interactions

Alpha-Lipoic Acid: Iron Salts may decrease the absorption of Alpha-Lipoic Acid. Alpha-Lipoic Acid may decrease the absorption of Iron Salts. Consider therapy modification

Antacids: May decrease the absorption of Iron Salts. Consider therapy modification

Baloxavir Marboxil: Iron Salts may decrease the serum concentration of Baloxavir Marboxil. Avoid combination

Bictegravir: Iron Salts may decrease the serum concentration of Bictegravir. Management: Bictegravir, emtricitabine, and tenofovir alafenamide can be administered with iron salts under fed conditions, but coadministration with or 2 hours after an iron salt is not recommended under fasting conditions. Consider therapy modification

Bisphosphonate Derivatives: Iron Salts may decrease the serum concentration of Bisphosphonate Derivatives. Management: Avoid administration of oral iron supplements within: 2 hours before or after tiludronate/clodronate/etidronate; 60 minutes after oral ibandronate; or 30 minutes after alendronate/risedronate. Exceptions: Pamidronate; Zoledronic Acid. Consider therapy modification

Cefdinir: Iron Salts may decrease the serum concentration of Cefdinir. Red-appearing, non-bloody stools may also develop due to the formation of an insoluble iron-cefdinir complex. Management: Avoid concurrent cefdinir and oral iron when possible. Separating doses by several hours may minimize interaction. Iron-containing infant formulas do not appear to interact with cefdinir. Consider therapy modification

Deferiprone: Iron Salts may decrease the serum concentration of Deferiprone. Management: Separate administration of deferiprone and oral medications or supplements that contain polyvalent cations by at least 4 hours. Consider therapy modification

Dimercaprol: May enhance the nephrotoxic effect of Iron Salts. Avoid combination

Dolutegravir: Iron Salts may decrease the serum concentration of Dolutegravir. Management: Administer dolutegravir at least 2 hours before or 6 hours after oral iron. Administer dolutegravir/rilpivirine at least 4 hours before or 6 hours after oral iron salts. Alternatively, dolutegravir and oral iron can be taken together with food. Consider therapy modification

Eltrombopag: Iron Salts may decrease the serum concentration of Eltrombopag. Management: Administer eltrombopag at least 2 hours before or 4 hours after oral administration of any iron-containing product. Consider therapy modification

Entacapone: Iron Salts may decrease the serum concentration of Entacapone. Management: Consider separating doses of the agents by 2 or more hours to minimize the effects of this interaction. Monitor for decreased therapeutic effects of levodopa during concomitant therapy, particularly if doses cannot be separated. Consider therapy modification

Ferric Hydroxide Polymaltose Complex: May decrease the serum concentration of Iron Salts. Specifically, the absorption of oral iron salts may be reduced. Management: Do not administer intravenous (IV) ferric hydroxide polymaltose complex with other oral iron salts. Therapy with oral iron salts should begin 1 week after the last dose of IV ferric hydroxide polymaltose complex. Consider therapy modification

Histamine H2 Receptor Antagonists: May decrease the absorption of Iron Salts. Monitor therapy

Iron Isomaltoside: May decrease the serum concentration of Iron Salts. Specifically, absorption of oral iron salts may be reduced. Management: Do not administer intravenous (IV) iron isomaltoside with other oral iron salts. Therapy with oral iron salts should begin 5 days after the last dose of IV iron isomaltoside. Consider therapy modification

Levodopa: Iron Salts may decrease the serum concentration of Levodopa. Only applies to oral iron preparations. Management: Consider separating doses of the agents by 2 or more hours to minimize the effects of this interaction. Monitor for decreased therapeutic effects of levodopa during concomitant therapy, particularly if doses cannot be separated. Consider therapy modification

Levothyroxine: Iron Salts may decrease the serum concentration of Levothyroxine. Management: Separate oral administration of iron salts and levothyroxine by at least 4 hours. Separation of doses is not required with parenterally administered iron salts or levothyroxine. Consider therapy modification

Methyldopa: Iron Salts may decrease the serum concentration of Methyldopa. Consider therapy modification

PenicillAMINE: Iron Salts may decrease the absorption of PenicillAMINE. Only oral iron salts are a concern. Management: Separate the administration of penicillamine and oral iron salts by at least 1 hour. Consider therapy modification

Phosphate Supplements: Iron Salts may decrease the absorption of Phosphate Supplements. Management: Administer oral phosphate supplements as far apart from the administration of an oral iron salt as possible to minimize the significance of this interaction. Exceptions: Sodium Glycerophosphate Pentahydrate. Consider therapy modification

Proton Pump Inhibitors: May decrease the absorption of Iron Salts. Monitor therapy

Quinolones: Iron Salts may decrease the serum concentration of Quinolones. Management: Give oral quinolones at least several hours before (4 h for moxi- and sparfloxacin, 2 h for others) or after (8 h for moxi-, 6 h for cipro/dela-, 4 h for lome-, 3 h for gemi-, and 2 h for levo-, nor-, oflox-, pefloxacin, or nalidixic acid) oral iron salts Exceptions: LevoFLOXacin (Oral Inhalation). Consider therapy modification

Tetracyclines: May decrease the absorption of Iron Salts. Iron Salts may decrease the serum concentration of Tetracyclines. Exceptions: Eravacycline. Consider therapy modification

Trientine: May decrease the serum concentration of Iron Salts. Iron Salts may decrease the serum concentration of Trientine. Management: Trientine manufacturer recommends avoiding concurrent use with oral iron salts due to the risk for impaired GI absorption of both trientine and the iron salt. Short courses of iron may be used; however, separate administration by at least 2 hours. Consider therapy modification

Test Interactions

False-positive for blood in stool by the guaiac test

Adverse Reactions

>10%: Gastrointestinal: Darkening of stools (≤80%; Tolkien 2015), abdominal pain (≤70%; Tolkien 2015), heartburn (1% to 68%; Tolkien 2015), nausea (≤63%; Tolkien 2015), constipation (≤39%; Tolkien 2015), flatulence (≤36%; Tolkien 2015), vomiting (≤34%; Tolkien 2015), diarrhea (≤23%; Tolkien 2015)

<1%, postmarketing, and/or case reports: Abdominal discomfort (Tolkien 2015)

Warnings/Precautions

Disease-related concerns:

• Gastrointestinal disease: Avoid in patients with peptic ulcer, enteritis, or ulcerative colitis.

Concurrent drug therapy issues:

• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Special populations:

• Blood transfusion recipients: Avoid in patients receiving frequent blood transfusions.

• Elderly: Anemia in the elderly is often caused by “anemia of chronic disease” or associated with inflammation rather than blood loss. Iron stores are usually normal or increased, with a serum ferritin >50 ng/mL and a decreased total iron binding capacity. Hence, the “anemia of chronic disease” is not secondary to iron deficiency but the inability of the reticuloendothelial system to reclaim available iron stores.

• Pediatric: Accidental overdose of iron-containing products is a leading cause of fatal poisoning in children under 6 years of age. Keep this product out of the reach of children. In case of accidental overdose call the poison control center immediately.

• Premature infants: Avoid use in premature infants until the vitamin E stores, deficient at birth, are replenished.

Dosage form specific issues:

• Oral iron formulations: Immediate release oral iron products are preferred for treatment of iron deficiency anemia; enteric coated and slow/sustained release preparations are not desired due to poor absorption (Hershko 2014; Liu 2012).

• Polysorbate 80: Some dosage forms may contain polysorbate 80 (also known as Tweens). Hypersensitivity reactions, usually a delayed reaction, have been reported following exposure to pharmaceutical products containing polysorbate 80 in certain individuals (Isaksson 2002; Lucente 2000; Shelley 1995). Thrombocytopenia, ascites, pulmonary deterioration, and renal and hepatic failure have been reported in premature neonates after receiving parenteral products containing polysorbate 80 (Alade 1986; CDC 1984). See manufacturer's labeling.

• Propylene glycol: Some dosage forms may contain propylene glycol; large amounts are potentially toxic and have been associated hyperosmolality, lactic acidosis, seizures, and respiratory depression; use caution (AAP 1997; Zar 2007).

Other warnings/precautions:

• Duration of therapy: Administration of iron for >6 months should be avoided except in patients with continuous bleeding or menorrhagia.

Monitoring Parameters

Iron deficient anemia: Hemoglobin and hematocrit; consider additional tests such as RBC count, RBC indices, serum ferritin, transferrin saturation, total iron-binding capacity, serum iron concentration, and erythrocyte protoporphyrin concentration (CDC 1998)

Cancer and chemotherapy-induced anemia: Serum iron, total iron-binding capacity, transferrin saturation, or ferritin levels (baseline and periodic) (Rizzo 2010)

CKD associated anemia (patients not on dialysis): To monitor response to iron therapy: Hemoglobin, serum ferritin, transferrin saturation (KDIGO 2013)

Pregnancy Considerations

Iron crosses the placenta and fetal stores are obtained from the mother (McArdle 2011). Iron requirements are increased in pregnant women compared to nonpregnant females (IOM 2001). All pregnant women should be tested for iron deficiency anemia and treated with supplemental iron if needed (ACOG 2008; CDC 1998). Untreated iron deficiency anemia during pregnancy may be associated with an increased risk of low birth weight, preterm delivery, and perinatal mortality, as well as postpartum depression in the mother and decreased mental functioning in the offspring (ACOG 2008; CDC 1998; IOM 2001). Treatment improves maternal hematologic status and neonatal birth weight (Haider 2013).

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience diarrhea; constipation; stool discoloration; lack of appetite; abdominal cramps; or staining of mouth, teeth, or fillings. Have patient report immediately to prescriber black, tarry, or bloody stools; severe nausea; severe vomiting; severe abdominal pain; or vomiting blood (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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