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Ferrous Sulfate

Iron Supplement

Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team

Species

Dog, Cat

Brands

2 available

Interactions

3 documented

Formulations

Mechanism of action

Provides ferrous iron (Fe2+) for hemoglobin synthesis, myoglobin, and iron-containing enzymes. Absorbed primarily in the duodenum and proximal jejunum. Essential for erythropoiesis — iron deficiency causes microcytic hypochromic anemia.

At a glance

Class

Iron Supplement

Schedule

OTC

Storage

Store at room temperature; keep away from children and pets — iron overdose is potentially fatal

Dosing

🐕

Dog

Used for iron deficiency anemia (chronic blood loss — GI parasites, GI tumors, c

Dose

5–10 mg/kg

Route

Frequency

q24h

🐈

Cat

Iron deficiency less common in cats

Dose

50–100 mg

Route

Frequency

q24h

Educational reference only

This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

Formulations

💊

Other — 3

Strength

—

Strength

—

Strength

—

Storage

Store at room temperature; keep away from children and pets — iron overdose is potentially fatal

Safety

Monitoring parameters

Serum iron and TIBC (iron saturation)Reticulocyte countPCV/hematocrit responseFerritin levels

Educational reference only

Interactions

Moderate — 3

Doxycycline

moderate

Iron chelates tetracyclines in GI tract forming poorly absorbed complexes. Reduces doxycycline absorption by 20-50%.

Management: Separate by 2-3 hours. Give doxycycline 2h before or 3h after iron.

Enrofloxacin

moderate

Iron chelates fluoroquinolones via multivalent cation binding, reducing enrofloxacin absorption by 25-50%.

Management: Separate by at least 2 hours.

Tetracycline

moderate

Iron chelates tetracycline in the GI tract, reducing absorption of both drugs.

Management: Separate by 2-3 hours.

Educational reference only

Brands

Other markets

Feosol

Fer-In-Sol

FAQs

Frequently asked questions

›What is Ferrous Sulfate?

Ferrous Sulfate is a iron supplement used in pets. Provides ferrous iron (Fe2+) for hemoglobin synthesis, myoglobin, and iron-containing enzymes. Absorbed primarily in the duodenum and proximal jejunum. Essential for erythropoiesis — iron deficiency causes microcytic hypochromic anemia.

›What is Ferrous Sulfate used for in pets?

Ferrous Sulfate is used in veterinary medicine for: Used for iron deficiency anemia (chronic blood loss — GI parasites, GI tumors, c; Iron deficiency less common in cats.

›What is the Ferrous Sulfate dose for dogs?

For dogs, Ferrous Sulfate is typically dosed as follows — Used for iron deficiency anemia (chronic blood loss — GI parasites, GI tumors, c: 5–10 mg/kg PO q24h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.

›What is the Ferrous Sulfate dose for cats?

For cats, Ferrous Sulfate is typically dosed as follows — Iron deficiency less common in cats: 50–100 mg PO q24h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.

›Does Ferrous Sulfate need a prescription?

Ferrous Sulfate is available over the counter. Even so, you should consult your veterinarian before giving any medication to your pet.

Educational reference only

References

The PetCare.AI drug reference is built from 13 authoritative sources cited across 580 drug monographs.

Textbooks & handbooks — 5

Plumb's Veterinary Drug Handbook
Withrow & MacEwen's Small Animal Clinical Oncology
Merck Veterinary Manual
NRC Nutrient Requirements of Dogs and Cats
Veterinary Pharmacology and Therapeutics (Riviere & Papich)

Clinical guidelines & consensus — 4

ASPCA Animal Poison Control Center Guidelines
AAHA Diabetes Management Guidelines
ASPCA Poison Control Guidelines
RECOVER CPR Guidelines

Journals & peer-reviewed studies — 2

EPIC Study (J Vet Intern Med 2016)
JVIM FAT CAT Study

Regulatory & approvals — 1

CDSCO Veterinary Drug Approval Registry (1969–2026)

Databases — 1

Washington State University VCPL MDR1 Database