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PetDosageChart

Proton pump inhibitor · For Cats

How much Omeprazole (Prilosec) can I give my cat?

Standard Omeprazole dose for cats is 0.75 mg per kg (0.34 mg per lb), given once daily. Use the calculator below for your cat's exact weight, or jump to the weight-by-weight chart.

Onset
1-3 days for full acid suppression
Duration
24 hours per dose
Class
Proton pump inhibitor

Calculator estimate from Plumb’s Veterinary Drug Handbook. Not yet vet-reviewed — see our methodology .

This dosage information is for educational purposes only. Always consult your veterinarian before giving any medication to your pet. Dosages may vary based on your pet's health conditions, other medications, and individual factors.

Content reviewed by licensed veterinarians. Sourced from Plumb's Veterinary Drug Handbook and the Merck Veterinary Manual.

Dosage Calculator · 01

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By Weight

Prilosec dose by cat weight

Pick your cat's weight to jump to a dedicated page with the dose, frequency, safety notes, and FAQ for that size.

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Dosage Chart · 02

Prilosec dosage for cats by weight

Scroll sideways to see full table

Weight Low Dose Standard Max Safe Frequency
3 lbs (1.4 kg) 0.5mg 1mg 1.5mg once daily
4 lbs (1.8 kg) 1mg 1.5mg 2mg once daily
5 lbs (2.3 kg) 1mg 1.5mg 2.5mg once daily
6 lbs (2.7 kg) 1.5mg 2mg 2.5mg once daily
7 lbs (3.2 kg) 1.5mg 2.5mg 3mg once daily
8 lbs (3.6 kg) 2mg 2.5mg 3.5mg once daily
9 lbs (4.1 kg) 2mg 3mg 4mg once daily
10 lbs (4.5 kg) 2.5mg 3.5mg 4.5mg once daily
12 lbs (5.4 kg) 2.5mg 4mg 5.5mg once daily
14 lbs (6.3 kg) 3mg 4.5mg 6.5mg once daily
16 lbs (7.3 kg) 3.5mg 5.5mg 7.5mg (10mg tablet) once daily
18 lbs (8.2 kg) 4mg 6mg 8mg (10mg tablet) once daily
20 lbs (9.1 kg) 4.5mg 7mg 9mg (10mg tablet) once daily
25 lbs (11.3 kg) 5.5mg 8.5mg (10mg tablet) 11.5mg (10mg tablet) once daily

Common Uses · 03

What is Prilosec (Omeprazole) used for in cats?

gastric ulcers acid reflux esophagitis Helicobacter gastritis NSAID-induced GI damage prevention

Administration · 04

How to give Prilosec 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.

Available Forms

capsule, tablet

Give with Food?

No — can be given without food

Side Effects · 05

Side effects of Prilosec in cats

Common side effects

decreased appetite
mild diarrhea
flatulence
nausea

Serious side effects — call your vet

  • severe diarrhea (C. difficile risk with prolonged use)
  • vitamin B12 malabsorption
  • rebound acid hypersecretion on discontinuation
  • liver enzyme elevation

Emergency · 06

When to call the vet

Call your vet immediately if your cat shows any of these signs:

  • 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)

For Dogs

Looking for Omeprazole dosage for dogs?

View the Omeprazole dosage chart and calculator for dogs.

Related · 08

Related medications for cats

Sources · 09

Sources & references

The dosage information on this page is compiled from the following veterinary and pharmaceutical references:

  • Plumb's Veterinary Drug Handbook — the standard veterinary pharmacology reference used by veterinarians worldwide.
  • Merck Veterinary Manual — a trusted, peer-reviewed resource for veterinary professionals and pet owners.
  • DailyMed (FDA Drug Labels) — official FDA-approved drug labeling and prescribing information for Omeprazole.

Read more about our methodology and how we calculate dosages.

Transparency · 11

How this page was made

Sourced from Plumb's Veterinary Drug Handbook, the reference used in US vet schools. Every dose, frequency, and tablet count on this page is generated from that data, then checked against the published references below.

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 rounds to the closest available tablet size.
Last-reviewed status
Automated from Plumb’s, not yet vet-reviewed.

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

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.

Safety · 10

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