# Famotidine: veterinary dose and monograph

> Famotidine is a veterinary gastrointestinal drug. Histamine H2-receptor antagonist — reduces gastric acid secretion. Indications include gastritis and gastric / duodenal ulceration; reflux oesophagitis; acid suppression in mast-cell tumour / uraemic gastropathy. This monograph lists 9 reference doses for dogs, cats, cattle, horses, rabbits and ferrets and 2 more species, each with route, frequency and source, plus meat and milk withdrawal periods for food animals.

Source: https://vetmasterji.com/drugs/famotidine · Last reviewed: 2026-10-01

## At a glance

- **Drug class:** Gastrointestinal
- **Also known as:** Pepcid, Famotid
- **Species with doses:** Dogs, Cats, Cattle, Horses, Rabbits, Ferrets, Hedgehogs and Primates
- **General dose range:** 0.5–1 mg/kg PO q12–24h — check the species tables for the indication
- **Routes:** PO, IV, SC
- **Last reviewed:** 1 October 2026

## Indications

- Gastritis and gastric / duodenal ulceration
- Reflux oesophagitis
- Acid suppression in mast-cell tumour / uraemic gastropathy
- Stress-ulcer prophylaxis in critical patients

## Famotidine dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

### Dogs

*Famotidine doses for dogs*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Acid suppression / ulcer | 0.5–1 mg/kg | PO | q12–24h | — |

- Acid suppression / ulcer: Papich 5e: 0.5 mg/kg q12h PO, IV, SC or IM; 1 mg/kg q12h for more reliable acid suppression; CRI 1 mg/kg IV load then 8 mg/kg/day. Plumb’s p.502: 0.5 mg/kg q12–24h (Matz); oesophagitis 0.5–1 mg/kg PO q12h; CKD 0.5 mg/kg once daily (Polzin 2005).

### Cats

*Famotidine doses for cats*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Acid suppression / uraemic gastritis | 0.2–1 mg/kg | PO | q12–24h | — |

- Acid suppression / uraemic gastritis: Papich 5e: 0.2 mg/kg q24h up to 0.25 mg/kg q12h IM, SC, PO or IV (IV slowly over 5 min). Plumb’s p.502: 0.2 mg/kg q24h (Marks 2008); 0.5 mg/kg q12–24h; CKD 0.5–1 mg/kg PO q12–24h (Zoran; Wolf). Plumb’s warns about IV use in cats (haemolysis) — give slowly or use another route.

### Cattle

*Famotidine doses for cattle*

| Indication | Dose | Route | Frequency | Duration | Withdrawal |
| --- | --- | --- | --- | --- | --- |
| Abomasal ulceration (calves, extra-label) | 0.4 mg/kg | IV | q6h | — | Withdrawal NOT established — treat as extra-label |

- Abomasal ulceration (calves, extra-label): Papich 5e: cattle 0.4 mg/kg IV q6h. Oral efficacy in ruminating cattle is limited. Extra-label — obtain a FARAD withdrawal.

### Horses

*Famotidine doses for horses*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Gastric ulceration (adjunct) | 0.2–0.4 mg/kg | IV | q6–12h | — |
| Gastric ulceration (oral) | 1–2.8 mg/kg | PO | q6–12h | — |

- Gastric ulceration (adjunct): Papich 5e: 0.2–0.4 mg/kg IV q6h. Plumb’s p.502 (Duran & Ravis 1993): 0.23 mg/kg IV q8h or 0.35 mg/kg IV q12h. ARCI Class 5.
- Gastric ulceration (oral): Papich 5e: 1–2 mg/kg q6–8h PO. Plumb’s p.502 (Duran & Ravis 1993): 1.88 mg/kg PO q8h or 2.8 mg/kg PO q12h. Omeprazole is more effective for EGUS.

### Buffalo

No buffalo-specific doses are on file, so buffalo are dosed as cattle.

*Famotidine doses for buffalo*

| Indication | Dose | Route | Frequency | Duration | Withdrawal |
| --- | --- | --- | --- | --- | --- |
| Abomasal ulceration (calves, extra-label) | 0.4 mg/kg | IV | q6h | — | Withdrawal NOT established — treat as extra-label |

- Abomasal ulceration (calves, extra-label): Papich 5e: cattle 0.4 mg/kg IV q6h. Oral efficacy in ruminating cattle is limited. Extra-label — obtain a FARAD withdrawal.

### Rabbits

*Famotidine doses for rabbits*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Stress-ulcer prophylaxis (critically ill) | 1 mg/kg | IV | q24h | — |

- Stress-ulcer prophylaxis (critically ill): Plumb's p.503 (Johnston 2006): rabbits 1 mg/kg IV once daily once the critically ill animal has stabilised.

### Ferrets

*Famotidine doses for ferrets*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Stress ulcer / Helicobacter adjunct | 0.25–0.5 mg/kg | PO | q24h | — |

- Stress ulcer / Helicobacter adjunct: Plumb's p.503 (Williams 2000; Fisher 2005): 0.25–0.5 mg/kg PO or IV once daily; part of Helicobacter mustelae therapy.

### Hedgehogs

*Famotidine doses for hedgehogs*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Gastric ulcer prevention / treatment | 1 mg/kg | SC | q24h | — |

- Gastric ulcer prevention / treatment: Carpenter Exotic Animal Formulary 6th ed, Table 8-7 (p.519): hedgehogs 1 mg/kg SC q24h.

### Primates

*Famotidine doses for primates*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Gastric / duodenal ulcer, oesophagitis | 0.5–0.8 mg/kg | PO | q24h | — |

- Gastric / duodenal ulcer, oesophagitis: Carpenter Exotic Animal Formulary 6th ed, Table 13-7 (p.707): 0.5–0.8 mg/kg PO q24h; more potent than cimetidine but poorer oral bioavailability (~37%).

## Contraindications

Significant renal impairment (reduce dose / frequency — renal elimination). Known hypersensitivity.

## Adverse effects

- Generally very well tolerated
- Rare: inappetence; intravascular haemolysis reported in cats with rapid IV — give slow / diluted

## Drug interactions

- Azole antifungals (ketoconazole, itraconazole, fluconazole): by RAISING gastric pH famotidine reduces their absorption — if both are needed, give the azole one hour BEFORE famotidine
- Cefpodoxime, cefuroxime: absorption may be decreased; giving with food may alleviate this
- Oral iron salts: absorption decreased — give iron at least one hour before famotidine
- Famotidine causes markedly fewer interactions than cimetidine, which inhibits hepatic P450 — this is the main reason to prefer it

## Toxicity and overdose

Plumb's p.502: a very wide margin of safety. The minimum acute lethal dose in dogs is reported as >2 g/kg orally and about 300 mg/kg intravenously. IV doses of 5–200 mg/kg in dogs produced vomiting, restlessness, mucous membrane pallor and redness of the mouth and ears; higher doses caused hypotension, tachycardia and collapse. Because of that margin most overdoses need only monitoring; consider gut-emptying protocols for a massive oral overdose and give supportive therapy where warranted.

## Clinical pearls

- Plumb's p.502 records two studies worth knowing: famotidine did NOT improve Helicobacter eradication when added to triple antibiotic therapy in dogs (Leib et al. 2007), and omeprazole was SUPERIOR to famotidine for preventing exercise-induced gastritis in racing sled dogs (Williamson et al. 2010)
- For true ulcer healing or severe oesophagitis a proton-pump inhibitor (omeprazole / pantoprazole) is superior — use H2 blockers for milder acid control
- Tolerance to the acid-suppressing effect can develop over ~2 weeks of continuous use
- Dilute and give slowly IV in cats — rapid injection has caused intravascular haemolysis

## Mechanism of action

Plumb's p.502: H2-receptor antagonist. At the H2 receptors of gastric parietal cells famotidine COMPETITIVELY inhibits histamine, reducing acid output both basally and when stimulated by food, pentagastrin, histamine or insulin. By cutting the volume of gastric juice it also reduces pepsin secretion. Note what it does NOT do: gastric emptying time, pancreatic and biliary secretion, and lower oesophageal pressure are unaltered — so it is an acid reducer, not a prokinetic. Incompletely absorbed orally with only minimal first-pass metabolism (human bioavailability 40–50%); only 15–20% protein bound; in rats it does not cross the blood-brain barrier or placenta but IS distributed into milk. Compared with cimetidine it has fewer drug interactions and its activity may persist longer.

## Formulations and products

- Famotidine 10 mg tablet
- Famotidine 20 mg tablet
- Famotidine 10 mg/mL injection

## Before you use this dose

> **Caution:** Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

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- [Metoclopramide](https://vetmasterji.com/drugs/metoclopramide)

## Frequently asked questions

### What is the dose of Famotidine for dogs?

Reference doses for Famotidine in dogs: 0.5–1 mg/kg PO q12–24h (Acid suppression / ulcer). Confirm against the label and the patient before use.

### What is the dose of Famotidine for cats?

Reference doses for Famotidine in cats: 0.2–1 mg/kg PO q12–24h (Acid suppression / uraemic gastritis). Confirm against the label and the patient before use.

### What is the dose of Famotidine for cattle?

Reference doses for Famotidine in cattle: 0.4 mg/kg IV q6h (Abomasal ulceration (calves, extra-label)). Confirm against the label and the patient before use.

### What is the withdrawal period for Famotidine?

Cattle, IV (Abomasal ulceration (calves, extra-label)): Withdrawal NOT established — treat as extra-label. Follow the product label and national regulations where they differ.

### When should Famotidine not be used?

Significant renal impairment (reduce dose / frequency — renal elimination). Known hypersensitivity.

### What are the side effects of Famotidine in animals?

Generally very well tolerated; Rare: inappetence; intravascular haemolysis reported in cats with rapid IV — give slow / diluted.

## Sources

- Plumb's Veterinary Drug Handbook
- Papich, Papich Handbook of Veterinary Drugs, 5th edition
- Carpenter, Exotic Animal Formulary

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VetMasterJi is a clinical decision-support and education platform for veterinary professionals and students. It does not provide veterinary advice, diagnosis or treatment for specific animals. All drug doses, calculators and differentials are references that must be independently verified before clinical use; the attending registered veterinarian remains solely responsible for every clinical decision.