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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

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

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

💊

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

Educational reference only

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).

Educational reference only

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.

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

Related medicines

Other medicines in the same class (Histamine H2-receptor antagonist).

Ranitidine

Competitively blocks H2 receptors on parietal cells, reducing acid secretion; also has prokinetic activity by inhibiting acetylcholinesterase

dogcat