Medically reviewed by Drugs.com. Last updated on Dec 26, 2018.
(FER us SUL fate)
- Feosol Original
- Ferric Sulfate
- Ferrous Sulphate
- Iron Sulfate
- Slow FE
Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product
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)
Generic: 220 (44 Fe) MG/5ML (473 mL)
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)
Generic: 300 (60 Fe) MG/5ML (5 mL)
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 [gluten free, sodium free; contains brilliant blue fcf (fd&c blue #1), fd&c blue #2 (indigotine), fd&c red #40, fd&c yellow #6 (sunset yellow)]
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 [DSC]
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]
- Iron Salt
Replaces iron, found in hemoglobin, myoglobin, and other enzymes; allows the transportation of oxygen via hemoglobin
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
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
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]]
Hypersensitivity to iron salts or any component of the formulation; hemochromatosis, hemolytic anemia
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). Doses are 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: Oral: 65 to 200 mg/day (Liu 2012; Schrier 2019; Stoltzfus 1998; WHO 2001); may administer in up to 3 divided doses (depending on formulation). Note: Alternate-day dosing (eg, every other day or Monday, Wednesday, Friday) has been shown to result in greater absorption of iron; some experts recommend this dosing schedule in patients who can maintain adherence (Schrier 2019; Stoffel 2017).
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])
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).
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.
Note: Doses 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 iron/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 of age if breastfed (full or partial) (Baker 2010; Schanler 2011)
Infants ≥6 months and Children <2 years in areas where anemia prevalence is >40%: 10 to 12.5 mg daily for 3 consecutive months in a year (WHO 2016b)
Children 2 years to <5 years in areas where anemia prevalence is >40%: 30 mg daily for 3 consecutive months in a year (WHO 2016b)
Children ≥5 to 12 years in areas where anemia prevalence is >40%: 30 to 60 mg daily for 3 consecutive months in a year (WHO 2016b)
Adolescent menstruating females (nonpregnant females of reproductive potential) in areas where anemia prevalence is >40%: 30 to 60 mg daily for 3 consecutive months in a year (WHO 2016a)
Treatment of iron deficiency: Infants, Children, and Adolescents: 3 to 6 mg/kg/day in 3 divided doses; suggested maximum daily dose: 200 mg/day (ASPEN Pediatric Nutrition Support Core Curriculum [Corkins 2015]; Kliegman 2016)
Oral: Do not chew or crush extended-release preparations; administer with water or juice on an empty stomach.
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
Iron is a leading cause of fatal poisoning in children. Store out of children's reach and in child-resistant containers.
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
False-positive for blood in stool by the guaiac test
>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)
• 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.
• 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).
• Duration of therapy: Administration of iron for >6 months should be avoided except in patients with continuous bleeding or menorrhagia.
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)
Maternal iron requirements increase during pregnancy. Adequate iron concentrations to the fetus can be maintained regardless of maternal iron status, except in severe cases of anemia (IOM 2001). Untreated iron deficiency and iron deficiency anemia (IDA) in a pregnant female may be associated with adverse events, including low birth weight, preterm birth, or increased perinatal mortality (ACOG 95 2008; IOM 2001; Pavord 2012).
In general, treatment of iron deficiency or IDA in pregnancy is the same as in non-pregnant females. The majority of studies note iron therapy improves maternal hematologic parameters; however, information related to clinical outcomes in the mother and neonate is limited (Peña-Rosas 2015; Reveiz 2011; Siu 2015). Oral preparations are generally sufficient; however, parenteral iron therapy may be used in females who cannot tolerate or will not take oral iron, in cases of severe iron deficiency, or when malabsorption is present (ACOG 95 2008; Pavord 2012). Ferrous sulfate has been evaluated in multiple studies as an iron supplement or for the treatment of IDA in pregnancy (Peña-Rosas 2015; Reveiz 2011). Enteric-coated and slow/sustained-release preparations may be less effective (ACOG 95 2008).
• 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.
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