ferrous sulfate

Medically Reviewed on 4/2/2022

Generic Name: ferrous sulfate

Brand Names: Slow FE, Fer-In-Sol, Feratab, Iron, Mol-Iron, Feosol, MyKidz Iron 10

Drug Class: Iron Products

What is ferrous sulfate, and what is it used for?

Ferrous sulfate is a synthetic iron supplement used to treat iron deficiency and iron deficiency anemia, when dietary sources are inadequate to maintain healthy levels of iron. Iron is an important component of hemoglobin, the protein in red blood cells that delivers oxygen to all the tissues, and myoglobin, the muscle protein that stores oxygen and releases it to the muscle cells when oxygen saturation drops.

In addition to oxygen transport and storage, iron is essential for many cellular processes, synthesis of enzymes and hormones, DNA synthesis and repair, electron transport and energy metabolism. In general, women need more iron intake because of loss of iron with menstrual bleeding, and pregnant women often need iron supplements because their requirement goes up during pregnancy and breastfeeding.

Dietary iron sources include

  • lean meat,
  • poultry,
  • seafood,
  • kidney beans,
  • lentils,
  • spinach,
  • peas,
  • nuts and
  • certain fortified foods.


  • Do not take ferrous sulfate if you are hypersensitive to iron salts, or any component of ferrous sulfate
  • Do not take if you have hemochromatosis, a condition in which excessive iron builds up in the body
  • Do not take ferrous sulfate if you have hemolytic anemia, which is caused by rapid destruction of red blood cells; the iron released from the red blood cells is reused
  • Avoid ferrous sulfate use in patients who receive frequent blood transfusions
  • Avoid use in patients with gastrointestinal conditions such as peptic ulcer disease, ulcerative colitis and enteritis
  • Avoid use in premature infants until vitamin E stores, which are deficient at birth, are replenished
  • Avoid administering iron for longer than 6 months except in patients with continuous bleeding or prolonged menstrual bleeding (menorrhagia)
  • Anemia in the elderly is often caused by chronic disease or associated with inflammation rather than blood loss, and hence not induced by iron deficiency; avoid use
  • Some dosage forms of ferrous sulfate may contain propylene glycol; large amounts are potentially toxic

What are the side effects of ferrous sulfate?

Common side effects of ferrous sulfate include:

Rare side effects include:

  • Gastrointestinal hemorrhage
  • Gastrointestinal obstruction (wax matrix products)
  • Gastrointestinal perforation

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug.

Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.


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What are the dosages of ferrous sulfate?

Oral solution

  • 220mg (44mg Fe)/5mL
  • 300mg (60mg Fe)/5mL (adult only)
  • 15 mg elemental Fe/mL

Oral liquid drops

  • 75mg (15mg Fe)/mL


  • 45mg elemental Fe
  • 200mg (65mg Fe)
  • 300mg (60mg Fe)
  • 325mg (65mg Fe)

Tablet, delayed release

  • 325mg (65mg Fe)

Tablet, extended release

  • 160mg (50mg Fe)
  • 142mg (45 mg Fe)
  • 140mg (45 mg Fe)


Recommended Daily Allowance (Elemental Iron)

19-50 years:

  • Males: 8 mg/day
  • Females: 18 mg/day
  • Pregnant females: 27 mg/day
  • Lactating females: 9 mg/day

Older than 50 years

  • 8 mg/day

Iron Deficiency Anemia

Treatment expressed as elemental iron

  • 100-200 mg orally divided every 12 hours; may administer extended-release form once daily

Prophylaxis is expressed as elemental iron

  • 60 mg orally once daily


Recommended Daily Allowance (Elemental Iron)

  • Children 0-6 months: 0.27 mg/day
  • Children 6-12 months: 11 mg/day
  • Children 1-3 years: 7 mg/day
  • Children 3-8 years: 10 mg/day
  • Children 8-13 years: 8 mg/day
  • Children over 13 years:
  • Males: 11 mg/day
  • Females: 15 mg/day
  • Pregnant females: 27 mg/day
  • Lactating females: 10 mg/day

Iron Deficiency Anemia

Treatment expressed as elemental iron

  • 3-6 mg Fe/kg/day orally divided every 8 hours

Prophylaxis is expressed as elemental iron

  • Children 4 months and older receiving human milk as an only nutritional source or greater than 50% as a source of nutrition: 1 mg/kg/day orally
  • Children 6 months to 2 years in areas where anemia prevalence is greater than 40% and iron-fortified food is not available: 2 mg/kg/day
  • Children 2-5 years in areas where anemia prevalence greater than 40%: 2 mg/kg/day orally; not to exceed 30 mg/day
  • Children over 5 years in areas where anemia prevalence greater than 40%: 30 mg/day with folic acid
  • Adolescents in areas where anemia prevalence is greater than 40%: 60 mg/day with folic acid


  • For maximum absorption, an agent should be taken on an empty stomach but may be taken with or after meals to minimize gastrointestinal (GI) irritation
  • Vitamin C may enhance absorption


  • Accidental overdose of iron-containing products is a leading cause of fatal poisoning in children under 6.
  • Iron overdose affects the gastrointestinal, cardiovascular and the central nervous systems causing multiple symptoms.
  • The treatment for iron overdose includes administration of deferoxamine, the antidote for iron, gastric lavage with sodium bicarbonate and other supportive and symptomatic therapies. The patient should be monitored for 24 hours after they become symptom free.

What drugs interact with ferrous sulfate?

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

Pregnancy and breastfeeding

  • Iron requirement increases during pregnancy, and untreated iron deficiency and iron deficiency anemia can increase the risk for low birth weight, preterm birth, or newborn mortality
  • Supplemental ferrous sulfate intake during pregnancy is desirable in order to prevent iron deficiency, however, it should not exceed the daily recommended dose
  • Iron deficiency during pregnancy should be treated with ferrous sulfate and iron supplementation should continue for 3 months after hemoglobin levels are normal, and for at least 6 months after delivery to replenish the mother’s iron stores
  • Iron is present in breast milk and ferrous sulfate use increases iron content in the milk; iron is a beneficial mineral nutrient for the breastfeeding baby and ferrous sulfate not exceeding the recommended daily dose is compatible with breastfeeding as per the World Health Organization guidelines

What else should I know about ferrous sulfate?

  • Do not take ferrous sulfate in excess of the daily recommended dose.
  • Keep ferrous sulfate out of reach of children. In case of accidental overdose, seek medical help or contact Poison Control immediately.


Ferrous sulfate is a synthetic iron supplement used to treat iron deficiency and iron deficiency anemia. Common side effects of ferrous sulfate include dark stools, abdominal pain or discomfort, heartburn, nausea, vomiting, constipation, flatulence, diarrhea, gastrointestinal irritation, contact irritation, urine discoloration, and superficial tooth discoloration (oral solutions). Accidental overdose of iron-containing products is a leading cause of fatal poisoning in children under 6. Do not exceed the recommended dose of ferrous sulfate.

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Medically Reviewed on 4/2/2022