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Famotidine

Prescription
Histamine H2-receptor antagonist
Last reviewed 19 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
3 available
Interactions
2 documented
Formulations
4

Mechanism of action

Competitively blocks histamine H2 receptors on parietal cells, reducing basal and stimulated gastric acid secretion

At a glance

Class
Histamine H2-receptor antagonist
Schedule
Prescription
Storage
Store below 30°C, protect from moisture

Dosing

🐕

Dog

Gastric/duodenal ulcers / Gastritis / Esophagitis / Acid-related GI disorders
Dose
0.5–1 mg/kg
Route
PO, IV, SC
Frequency
BID
Max dose
40 mg/dose; 80 mg/day
Duration: 5–14 days or as needed
🐈

Cat

Gastric/duodenal ulcers / Uremic gastritis
Dose
0.5–1 mg/kg
Route
PO, IV, SC
Frequency
SID to BID
Max dose
10 mg/dose; 20 mg/day
Duration: 5–14 days

Formulations

💊

Tablet — 3

Strength
10mg
Available in India
Strength
20mg
Available in India
Strength
40mg
Available in India
💉

Injection — 1

Strength
20mg/2mL
Available in India

Storage

Store below 30°C, protect from moisture

Safety

Absolute contraindications — do not use

  • Known hypersensitivity to H2 antagonists

Use with caution

  • Renal impairment
    Dose reduction recommended
  • Concurrent ketoconazole or itraconazole
    Reduced azole absorption

Adverse effects

Common
Generally well tolerated
Serious
Rare: thrombocytopenia
Cardiac arrhythmias with rapid IV injection

Monitoring parameters

Clinical response (GI symptoms)Renal function in CKD patients

Interactions

Moderate — 1

Ketoconazole
moderate
H2 blockers raise gastric pH; ketoconazole requires acidic environment for absorption
Management: Give ketoconazole at least 2 hours before famotidine, or use fluconazole instead (pH-independent absorption).

Minor — 1

Doxycycline
minor
Doxycycline absorption is minimally affected by gastric pH changes (unlike other tetracyclines). However, concurrent H2-blockers may modestly reduce absorption.
Management: Usually clinically insignificant for doxycycline specifically. No dose separation typically needed (unlike with other tetracyclines and antacids).

Brands

International

Pepcid
Merck

India

Famocid
Sun Pharma
Topcid
Zydus

FAQs

Frequently asked questions

›What is Famotidine?
Famotidine is a histamine h2-receptor antagonist used in pets. Competitively blocks histamine H2 receptors on parietal cells, reducing basal and stimulated gastric acid secretion
›What is Famotidine used for in pets?
Famotidine is used in veterinary medicine for: Gastric/duodenal ulcers / Gastritis / Esophagitis / Acid-related GI disorders; Gastric/duodenal ulcers / Uremic gastritis.
›What is the Famotidine dose for dogs?
For dogs, Famotidine is typically dosed as follows — Gastric/duodenal ulcers / Gastritis / Esophagitis / Acid-related GI disorders: 0.5–1 mg/kg PO/IV/SC BID. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Famotidine dose for cats?
For cats, Famotidine is typically dosed as follows — Gastric/duodenal ulcers / Uremic gastritis: 0.5–1 mg/kg PO/IV/SC SID to BID. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What are the side effects of Famotidine?
Common: Generally well tolerated. Serious (call your vet immediately): Rare: thrombocytopenia, Cardiac arrhythmias with rapid IV injection.
›Does Famotidine need a prescription?
Yes. Famotidine is a prescription medication and should only be administered under veterinary supervision.
›When should Famotidine not be used?
Do not use Famotidine if: Known hypersensitivity to H2 antagonists.

References

References

Textbooks & handbooks

  • Plumb, D.C. Plumb's Veterinary Drug Handbook. 10th ed., Wiley-Blackwell, 2023.
  • Vail, D.M., Thamm, D.H., & Liptak, J.M. (eds.). Withrow & MacEwen's Small Animal Clinical Oncology. 6th ed., Saunders/Elsevier, 2020.
  • Riviere, J.E., & Papich, M.G. (eds.). Veterinary Pharmacology and Therapeutics. 10th ed., Wiley-Blackwell, 2018.
  • National Research Council. Nutrient Requirements of Dogs and Cats. National Academies Press, Washington DC, 2006.
  • The Merck Veterinary Manual. Merck & Co., Online edition. https://www.merckvetmanual.com/

Clinical guidelines & consensus

  • Fletcher, D.J., Boller, M., Brainard, B.M., et al. "RECOVER Evidence and Knowledge Gap Analysis on Veterinary CPR." Journal of Veterinary Emergency and Critical Care, 2012;22(S1):S102–S131.
  • American Animal Hospital Association. 2018 AAHA Diabetes Management Guidelines for Dogs and Cats. AAHA Press.

Journals & peer-reviewed studies

  • Hogan, D.F., Fox, P.R., Jacob, K., et al. "Secondary prevention of cardiogenic arterial thromboembolism in the cat: The FAT CAT study." Journal of Veterinary Cardiology, 2015;17(Suppl 1):S306–S317.
  • Boswood, A., Häggström, J., Gordon, S.G., et al. "Effect of Pimobendan in Dogs with Preclinical Myxomatous Mitral Valve Disease and Cardiomegaly: The EPIC Study — A Randomized Clinical Trial." Journal of Veterinary Internal Medicine, 2016;30(6):1765–1779.
  • ASPCA Animal Poison Control Center. Toxicology and Poison Management Guidelines. American Society for the Prevention of Cruelty to Animals. https://www.aspca.org/pet-care/animal-poison-control

Regulatory & approvals

  • Central Drugs Standard Control Organisation (CDSCO), Government of India. Veterinary Drug Approval Registry, 1969–2026. Directorate General of Health Services. https://cdsco.gov.in/

Databases

  • Washington State University, College of Veterinary Medicine. Veterinary Clinical Pharmacology Laboratory (VCPL) — MDR1 Multidrug Sensitivity Database. https://vcpl.vetmed.wsu.edu/
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 →

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