Omeprazole is a proton pump inhibitor (PPI) used to reduce stomach acid production in dogs and cats. It is one of the most commonly prescribed gastrointestinal medications in UK veterinary practice, used for gastric ulcers, gastro-oesophageal reflux, and NSAID-induced stomach damage.

Price Comparison

  • Veterinary-branded omeprazole (e.g., Omeprazole for Dogs): £15–£35 per month from your vet
  • Online pharmacies (with vet prescription): £5–£15 per month
  • Human omeprazole (prescribed under the cascade): £3–£10 per month from pharmacies

Omeprazole is one of the medications where the biggest savings can be made through online purchasing. Human-licensed omeprazole capsules prescribed under the veterinary cascade are significantly cheaper than veterinary-branded products and are identical in formulation.

What Does Omeprazole Treat?

  • Gastric and duodenal ulcers
  • NSAID-induced gastric erosions and ulcers (protective use alongside long-term NSAID therapy)
  • Gastro-oesophageal reflux disease (GORD)
  • Helicobacter-associated gastritis
  • Mast cell tumour-related gastric acid hypersecretion

Species and Forms

  • Dogs: Capsules (10mg, 20mg) or enteric-coated tablets. Dosed at 0.5–1mg/kg once daily
  • Cats: Capsules (10mg). Dosed at 0.5–1mg/kg once daily. Capsules can be difficult to give to cats

Important: Omeprazole capsules should not be crushed or opened as the enteric coating protects the drug from stomach acid. Administer whole capsules.

Side Effects

  • Generally very well tolerated
  • Occasional diarrhoea or changes in stool consistency
  • Long-term use may affect nutrient absorption (particularly magnesium and vitamin B12)
  • Rebound acid hypersecretion can occur if stopped abruptly after prolonged use — taper gradually

Prescription Requirements

When prescribed for animals, omeprazole requires a veterinary prescription. However, human omeprazole is available over the counter — do not self-medicate your pet without veterinary guidance on dosing and diagnosis.

How to Save

  • Written prescription for human omeprazole: Ask your vet to prescribe human-licensed omeprazole under the cascade — savings of 60–80% compared to veterinary brands
  • Online pharmacies: Even veterinary-branded omeprazole is 40–60% cheaper online
  • Buy in bulk: Larger packs of 28 capsules are cheaper per unit than smaller packs
  • Compare prices: Use VetCost to compare pharmacy prices

Last updated: March 2026. Sources: VMD, BSAVA formulary, CMA provisional decision (October 2025), VetCost pharmacy data.