Proton pump inhibitor · For Cats

Omeprazole dosage reference for cats (Prilosec)

This page's standard weight-based reference is 0.75 mg per kg (0.34 mg per lb), with once daily 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: 1-3 days for full acid suppression
Duration: 24 hours per dose
Class: Proton pump inhibitor

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.

Omeprazole (often known by brand names such as Prilosec and Losec) is a proton pump inhibitor commonly used in veterinary medicine for gastric ulcers, acid reflux, esophagitis, Helicobacter gastritis, and NSAID-induced GI damage prevention. Understanding the correct dosage, administration, and potential side effects of Omeprazole is critical for your cat’s safety and well-being.

A typical Omeprazole dose for cats is around 0.75 mg/kg once daily, within a usual range of 0.5-1 mg/kg. Available forms include capsule and tablet.

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.

Omeprazole Dosage Calculator for Cats

Enter your cat’s weight below to estimate the Omeprazole dose from the 0.75 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 Omeprazole amounts for common cat weights, for quick reference:

Dosage Chart · 02

Prilosec 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)	0.70 mg	1.0 mg	1.4 mg	once daily
4 lbs (1.8 kg)	0.90 mg	1.4 mg	1.8 mg	once daily
5 lbs (2.3 kg)	1.1 mg	1.7 mg	2.3 mg	once daily
6 lbs (2.7 kg)	1.4 mg	2.0 mg	2.7 mg	once daily
7 lbs (3.2 kg)	1.6 mg	2.4 mg	3.2 mg	once daily
8 lbs (3.6 kg)	1.8 mg	2.7 mg	3.6 mg	once daily
9 lbs (4.1 kg)	2.0 mg	3.1 mg	4.1 mg	once daily
10 lbs (4.5 kg)	2.3 mg	3.4 mg	4.5 mg	once daily
12 lbs (5.4 kg)	2.7 mg	4.1 mg	5.4 mg	once daily
14 lbs (6.3 kg)	3.1 mg	4.7 mg	6.3 mg	once daily
16 lbs (7.3 kg)	3.6 mg	5.5 mg	7.3 mg	once daily
18 lbs (8.2 kg)	4.1 mg	6.1 mg	8.2 mg (10mg tablet)	once daily
20 lbs (9.1 kg)	4.5 mg	6.8 mg	9.1 mg (10mg tablet)	once daily
25 lbs (11.3 kg)	5.7 mg	8.5 mg (10mg tablet)	11.3 mg (10mg tablet)	once daily

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

Prilosec 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 Omeprazole to Your Cat

Give omeprazole on an empty stomach, ideally 30 minutes before a meal for maximum acid suppression. Do NOT crush or break enteric-coated capsules or tablets, as this destroys the coating and the drug is degraded by stomach acid. For cats that cannot swallow capsules, compounding pharmacies can prepare an appropriate liquid formulation. If also giving sucralfate, give omeprazole at least 30 minutes before the sucralfate.

It may interact with sucralfate (separate by 30 minutes), ketoconazole (reduced absorption), diazepam (reduced clearance), and phenytoin.

Side Effects and Safety

Common side effects include decreased appetite, mild diarrhea, flatulence, and nausea. More serious side effects can occur, such as severe diarrhea (C. difficile risk with prolonged use), vitamin B12 malabsorption, rebound acid hypersecretion on discontinuation, and liver enzyme elevation.

Cautions · 12

When Prilosec should be used with caution or avoided

Some cats should not take Prilosec, 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 Prilosec.

known hypersensitivity to proton pump inhibitors
concurrent use with clopidogrel
severe liver disease
pregnancy

Interactions · 13

Prilosec drug interactions

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

sucralfate (separate by 30 minutes)

ketoconazole (reduced absorption)

diazepam (reduced clearance)

phenytoin

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 Prilosec, 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:

Black or tarry stools (sign of GI bleeding)
Persistent vomiting despite treatment
Severe diarrhea or blood in stool
Complete refusal to eat for more than 24 hours
Yellowing of gums or skin (liver concerns)

Frequently Asked Questions

Frequently Asked · 07

Questions about this medication

How long can a cat take omeprazole?

Short courses of 2-4 weeks are common for acute conditions like ulcers. Long-term use beyond 8 weeks should be under veterinary supervision, as prolonged acid suppression can affect nutrient absorption and gut flora. Your vet will taper the dose when discontinuing to avoid rebound acid hypersecretion.

Can I give my cat human omeprazole?

Human OTC omeprazole capsules (typically 10 or 20 mg) can be used for cats under veterinary guidance. The 10 mg capsule is most practical for cats. Do not use flavored, chewable, or combination products (like omeprazole/sodium bicarbonate). A compounding pharmacy can prepare accurate smaller doses if needed.

Why should I give omeprazole on an empty stomach?

Omeprazole works by binding to actively pumping acid pumps (proton pumps) in the stomach lining. These pumps are most active when stimulated by a meal. Giving the drug 30 minutes before food ensures peak drug levels coincide with maximum pump activity, resulting in the best acid suppression.

Is omeprazole better than famotidine for cats?

Omeprazole is significantly more effective at reducing stomach acid than famotidine (Pepcid). Omeprazole blocks acid production at the source (proton pump) and provides near-complete acid suppression, while famotidine only partially reduces acid via a different mechanism. For serious conditions like ulcers, omeprazole is preferred.

Can I suddenly stop giving my cat omeprazole?

Abruptly stopping omeprazole after prolonged use can cause rebound acid hypersecretion, where the stomach produces even more acid than before treatment. Your vet may recommend tapering the dose over 1-2 weeks or switching to a less potent acid reducer like famotidine during the transition.

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 Prilosec. It cannot decide whether this drug, indication, formulation, or schedule is appropriate for an individual animal.

Context in this medication record

Commonly listed uses: gastric ulcers, acid reflux, esophagitis, Helicobacter gastritis, NSAID-induced GI damage prevention
Recorded forms: capsule, tablet
Reference timing: once daily; onset 1-3 days for full acid suppression; duration 24 hours per dose

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 to proton pump inhibitors; concurrent use with clopidogrel; severe liver disease; pregnancy.

Recorded interactions

sucralfate (separate by 30 minutes); ketoconazole (reduced absorption); diazepam (reduced clearance); phenytoin.

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 Omeprazole — 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 0.75 mg per kg (0.34 mg per lb) of body weight, given once daily. 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