H2 receptor antagonist · For Cats

Famotidine dosage reference for cats (Pepcid)

This page's standard weight-based reference is 0.5 mg per kg (0.23 mg per lb), with every 12-24 hours recorded as the reference frequency. Use the calculator to see the arithmetic for your cat's weight, then confirm the indication, product, and actual dose with a veterinarian.

Onset: 30-60 minutes
Duration: 12-24 hours
Class: H2 receptor antagonist

Weight-based calculator estimate from the references listed on this page. This page has not been independently DVM-reviewed — see our methodology .

This information is for educational purposes only. Always consult your veterinarian before giving medication to your pet. Do not use this calculator for emergencies, overdoses, pregnancy, very young animals, very old animals, pets with liver/kidney disease, or pets taking multiple medications.

Each medication page lists the references recorded for its data. The calculator math and editorial presentation are maintained by PetDosageChart; a page is independently DVM-reviewed only when a named reviewer byline appears. See our methodology and limitations.

Famotidine (often known by brand names such as Pepcid) is an H2 receptor antagonist commonly used in veterinary medicine for stomach acid reduction, gastritis, acid reflux, and nausea. Understanding the correct dosage, administration, and potential side effects of Famotidine is critical for your cat’s safety and well-being.

A typical Famotidine dose for cats is around 0.5 mg/kg every 12-24 hours, within a usual range of 0.25-1 mg/kg. Available forms include tablet and injectable.

Calculator Warning: Use this only as an educational estimate. Your veterinarian may prescribe a different dose based on your pet’s condition, age, weight, other medications, and medical history.

Famotidine Dosage Calculator for Cats

Enter your cat’s weight below to estimate the Famotidine dose from the 0.5 mg/kg guideline. Your veterinarian may adjust it for your cat’s age, condition, and other medications, so treat the result as an educational starting point, not a prescription.

Dosage Calculator · 01

Enter your cat's weight

Quick Dosage Chart

Typical Famotidine amounts for common cat weights, for quick reference:

Dosage Chart · 02

Pepcid weight-based reference chart for cats

Scroll sideways to see full table

Weight	Lower Reference	Standard Reference	Upper Reference	Frequency
3 lbs (1.4 kg)	0.35 mg	0.70 mg	1.4 mg	every 12-24 hours
4 lbs (1.8 kg)	0.45 mg	0.90 mg	1.8 mg	every 12-24 hours
5 lbs (2.3 kg)	0.57 mg	1.1 mg	2.3 mg	every 12-24 hours
6 lbs (2.7 kg)	0.68 mg	1.4 mg	2.7 mg	every 12-24 hours
7 lbs (3.2 kg)	0.80 mg	1.6 mg	3.2 mg	every 12-24 hours
8 lbs (3.6 kg)	0.90 mg	1.8 mg	3.6 mg	every 12-24 hours
9 lbs (4.1 kg)	1.0 mg	2.0 mg	4.1 mg	every 12-24 hours
10 lbs (4.5 kg)	1.1 mg	2.3 mg	4.5 mg	every 12-24 hours
12 lbs (5.4 kg)	1.4 mg	2.7 mg	5.4 mg	every 12-24 hours
14 lbs (6.3 kg)	1.6 mg	3.1 mg	6.3 mg	every 12-24 hours
16 lbs (7.3 kg)	1.8 mg	3.6 mg	7.3 mg	every 12-24 hours
18 lbs (8.2 kg)	2.0 mg	4.1 mg	8.2 mg (10mg tablet)	every 12-24 hours
20 lbs (9.1 kg)	2.3 mg	4.5 mg	9.1 mg (10mg tablet)	every 12-24 hours
25 lbs (11.3 kg)	2.8 mg	5.7 mg	11.3 mg (10mg tablet)	every 12-24 hours

Parenthetical tablet amounts are arithmetic comparisons only. They do not account for scoring, release type, concentration, product labeling, or whether this medication is appropriate for an individual animal.

By Weight

Pepcid reference by cat weight

Choose a common weight to open its optional reference page. Use the main medication calculator for a different exact weight.

Common-weight pages are convenience views of the same educational reference, not separate medical recommendations.

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How to Give Famotidine to Your Cat

Famotidine tablets are small but may need to be cut for cat-sized doses. A pill cutter helps achieve the right dose. Give on an empty stomach 30-60 minutes before meals for best effect. You can also crush the tablet and mix with a small amount of wet food if your cat is difficult to pill.

It may interact with antacids, ketoconazole (reduced absorption), and sucralfate.

Side Effects and Safety

Common side effects include decreased appetite, drowsiness, and constipation. More serious side effects can occur, such as irregular heartbeat (rare), severe vomiting, and allergic reaction.

Cautions · 12

When Pepcid should be used with caution or avoided

Some cats should not take Pepcid, or need a different dose and closer monitoring. Tell your veterinarian about your pet's full health history and every other medication or supplement they take before giving Pepcid.

known hypersensitivity
severe kidney disease (dose adjustment needed)

Interactions · 13

Pepcid drug interactions

Pepcid can interact with other drugs. This list is not complete — always give your veterinarian a full list of your cat's medications and supplements.

antacids

ketoconazole (reduced absorption)

sucralfate

Calculator Limits · 14

When not to use this calculator

This calculator gives a general educational estimate for a healthy adult cat at a known weight. Do not rely on it in these situations — talk to your veterinarian instead:

In an emergency, or after accidental ingestion or a suspected overdose
For pregnant or nursing pets
For very young or very old cats
For pets with liver disease, kidney disease, or another chronic illness
For pets taking several medications at once
When you are not sure of your cat's current, accurate weight
For combination products that contain additional active ingredients

Overdose · 15

Suspected overdose: what to do

If you think your cat had too much Pepcid, or swallowed any medication by accident, act right away. Do not wait for symptoms to appear.

Call your veterinarian or the nearest emergency animal hospital.
ASPCA Animal Poison Control Center: (888) 426-4435
Pet Poison Helpline: (855) 764-7661

A consultation fee may apply to the poison hotlines. Have the medication packaging ready, and note how much your pet may have taken and when. Do not try to make your pet vomit unless a veterinarian tells you to.

When to Call the Vet

If your cat experiences any of the following, contact your veterinarian or an emergency clinic immediately:

Vomiting continues despite treatment
Refusing to eat for more than 24 hours
Blood in vomit or stool
Severe lethargy
Signs of allergic reaction

Frequently Asked Questions

Frequently Asked · 07

Questions about this medication

Can I give my cat Pepcid?

Yes, Pepcid (famotidine) is commonly used for cats with stomach acid issues, nausea, and gastritis. Use the original plain formula only. Many vets recommend it for cats with chronic kidney disease who experience nausea.

How much Pepcid can I give my cat?

The typical dose for cats is 0.25-0.5 mg per kilogram of body weight, given every 12-24 hours. For an average 10 lb (4.5 kg) cat, this is approximately 2.5 mg (one quarter of a 10 mg tablet) once or twice daily.

Can Pepcid help a cat with kidney disease?

Yes, famotidine is commonly prescribed for cats with chronic kidney disease (CKD) to help manage nausea and stomach acid buildup, which is common as kidney function declines. It can help improve appetite in cats with CKD.

How long can a cat take famotidine?

Famotidine can be used short-term for acute stomach issues or long-term for chronic conditions like CKD-related nausea. Long-term use is generally well-tolerated in cats. Your vet will determine the appropriate duration.

Use This Guide Safely · 08

What weight alone cannot tell you

The calculator performs one narrow job: it multiplies your cat's weight by the lower, standard, and upper mg/kg values recorded for Pepcid. It cannot decide whether this drug, indication, formulation, or schedule is appropriate for an individual animal.

Context in this medication record

Commonly listed uses: stomach acid reduction, gastritis, acid reflux, nausea
Recorded forms: tablet, injectable
Reference timing: every 12-24 hours; onset 30-60 minutes; duration 12-24 hours

Individual checks a calculator cannot perform

Confirm the diagnosis and the reason this medication is being considered.
Match the exact product, concentration, route, and whether a tablet may be split.
Account for age, pregnancy, organ function, genetics, allergies, and prior reactions.
Review every prescription, over-the-counter product, and supplement your pet takes.

Recorded cautions

known hypersensitivity; severe kidney disease (dose adjustment needed).

Recorded interactions

antacids; ketoconazole (reduced absorption); sucralfate.

These lists reproduce the structured record used by this page and may not be exhaustive. Show your veterinarian the product label and your cat's complete medication list before acting on a number.

Related · 08

Related medications for cats

Sources · 09

Sources & references

The structured medication record behind this page names the references below. The links open the publisher or official resource; they do not turn this page into a prescription for an individual animal.

Plumb's Veterinary Drug Handbook — listed in this medication's source record.
Merck Veterinary Manual — listed in this medication's source record.
DailyMed label search for Famotidine — check current product and formulation labels; some veterinary uses may be off-label.

Source names are shown at the record level; passage-level page and label citations are still being added. Read our methodology and limitations.

Transparency · 11

How this page was made

This page's structured medication record includes Plumb's Veterinary Drug Handbook among its source names. PetDosageChart applies the record's mg/kg values to the entered weight and presents the arithmetic result. A source record is not the same as an individualized prescription or an independent clinical review.

Sources cited: Plumb's Veterinary Drug Handbook
Merck Veterinary Manual
Calculator formula: Doses scale linearly from a standard basis of 0.5 mg per kg (0.23 mg per lb) of body weight, given every 12-24 hours. The calculator multiplies that basis by your cat's weight and shows an arithmetic comparison with recorded tablet sizes. That comparison does not determine whether a tablet is scored, splittable, or appropriate for your pet.
Editorial owner: Prepared and maintained by the PetDosageChart editorial team, a software-led publisher and not a veterinary practice.
DVM review status: Not independently DVM-reviewed. A named reviewer and review date appear here only after a confirmed review.

More on our methodology and editorial process — how we source, calculate, and review cats dosage data.

Safety · 10

More resources

Pet Medication Safety Hub — What's safe, what's dangerous, and emergency signs
How we calculate dosages — Our sources, math, and review process
Printable emergency checklist — One-page reference for your fridge or first aid kit