Prescribing overview
Suppresses gastric acid. Human Prilosec formulations and equine GastroGard have different authorization and administration instructions.
Key prescribing checks
- Reconcile interacting prescription medicines and other acid reducers before adding treatment. A name match alone does not establish combination safety.
- Evaluate ongoing vomiting, unexplained weight loss or gastrointestinal bleeding rather than treating an acid reducer as a diagnosis.
- Confirm the intended duration and clinical response with the prescriber. The human OTC label states that full effect may be delayed; it should not be represented as immediate relief for an acutely ill animal.
Uses by species
Approval and evidence apply to the named product, species, route and indication. An extra-label use requires its own prescribing assessment; a human indication is not an animal approval.
Dogs and cats
Extra-labelAcid suppression
Human preparations require veterinary prescribing; animal dose not verified here.
Use / indication source ↗Horses and foals
FDA-approvedGastric ulcers and recurrence prevention
Age 4 weeks or older; GastroGard only.
Use / indication source ↗Pharmacology & pharmacokinetics
Mechanism and clinical role
Inhibits the gastric acid secretory proton pump.
Absorption, distribution, metabolism and elimination
Animal-specific pharmacokinetic parameters were not established by the reviewed label.
SAFETY REFERENCE · PRODUCT & SPECIES SPECIFIC
Contraindications & cautions
Contraindications identify circumstances where the source says a product should not be used. Precautions call for assessment or monitoring. Interactions identify combinations to review. They are distinct categories; this summary does not replace a full interaction check or the current product label.
Prilosec
Human delayed-release capsules; historical Prilosec brand identity plus current generic capsule-label safety support. Veterinary use is extra-label.
Contraindications · when not to use
- Allergy to substituted benzimidazoles or formulation ingredients; concurrent rilpivirine-containing products.
Precautions & monitoring
- Current capsule labeling warns about kidney inflammation, severe skin reactions, persistent diarrhea and low magnesium with prolonged use.
Prilosec OTC
Human OTC delayed-release tablets; Drug Facts restrictions apply to human self-treatment.
Contraindications · when not to use
A formal contraindication list is not established in the reviewed source for this scope. This does not establish safety; confirm the exact product and full labeling.
Precautions & monitoring
- Do not use with omeprazole allergy, painful/difficult swallowing, gastrointestinal bleeding or listed concerning chest/heartburn symptoms. Persistent symptoms, weight loss, nausea, vomiting or abdominal pain require clinician review.
GastroGard
Equine 37% oral paste only; not Prilosec human formulations.
Contraindications · when not to use
A formal contraindication list is not established in the reviewed source for this scope. This does not establish safety; confirm the exact product and full labeling.
Precautions & monitoring
- Not for food horses. Pregnancy/lactation safety and use beyond 91 days are unestablished. Label has no separate contraindication list.
Human OTC do-not-use warnings are not veterinary contraindications. Current capsule safety is supported by the separately identified generic label; check the actual dispensing product.
Safety sources checked: . Selected label information; independent veterinary or veterinary-pharmacy review remains pending. A label for dogs, cats, horses or humans does not establish safety for another species.
Adverse effects
Human labels report gastrointestinal upset and warn of nephritis, severe skin reactions and prolonged-use hypomagnesemia; animal incidence is not established here.
These are selected source-reported effects, not incidence estimates or an exhaustive list. Spontaneous postmarketing reports do not by themselves establish frequency or causality.
Dosing & administration
| Species & indication | Labeled regimen | Eligibility & source |
|---|---|---|
| Horses and foalsGastric ulcer treatmentGastroGard 37% oral paste | 4 mg/kg Oral · Once daily 4 weeks | Age ≥4 weeks; follow calibrated syringe instructions. Verify full dosing label ↗ |
| Horses and foalsPrevention of gastric ulcer recurrenceGastroGard 37% oral paste | 2 mg/kg Oral · Once daily At least 4 additional weeks after treatment | Age ≥4 weeks. Verify full dosing label ↗ |
No verified canine/feline regimen is supplied.
Extra-label prescribing and food-animal residue requirements are separate from labeled regimens. FDA extra-label-use guidance ↗
Drug & supplement interactions
This is a selected interaction reference, not an automated or comprehensive combination checker. Reconcile prescription drugs, nonprescription products, supplements and recent treatment changes.
Prilosec
Human delayed-release capsules; historical Prilosec brand identity plus current generic capsule-label safety support. Veterinary use is extra-label.
- Avoid clopidogrel, rifampin and St. John’s wort combinations; methotrexate exposure can increase.
Prilosec OTC
Human OTC delayed-release tablets; Drug Facts restrictions apply to human self-treatment.
- Drug Facts directs prescription-drug users to ask a clinician or pharmacist about interactions.
Monitoring
Reassess bleeding, persistent vomiting and treatment need; review interactions.
Client counseling
Do not crush delayed-release granules or transfer human OTC courses to animals.
This section supports the veterinary team's discharge discussion; it does not replace the product’s Client Information Sheet where one is required.
Storage & handling
Follow the dispensed formulation; GastroGard: 20–25°C.
Brands, formulations & ingredient identity
Active ingredients
Omeprazole
Other searchable names: Omeprazole magnesium
Prilosec and Prilosec OTC identify omeprazole-containing products. The magnesium salt may appear on packaging even when the chart uses the shorter generic name.
Delayed-release capsules and tablets have different administration instructions. Crushing, chewing or changing the preparation can defeat the protective delivery system; consult the exact product label.
A human brand or OTC course does not provide a canine, feline or equine protocol. Other species-specific omeprazole products require their own labeling review.
Shared ingredients do not establish interchangeable concentrations, routes, release properties, species labeling or regional availability.
Prilosec
- Formulation
- Delayed-release oral capsules
- Label / product scope
- Human product
Human product identity verified by official labeling; availability and exact packaging require confirmation.
Product label / source ↗Prilosec OTC
- Formulation
- Delayed-release oral tablets
- Label / product scope
- Human product
Human OTC formulation; do not substitute its administration instructions for a veterinary prescription.
Product label / source ↗GastroGard
- Formulation
- 37% w/w omeprazole oral paste in calibrated syringe
- Label / product scope
- Horses · Foals
FDA-approved equine ulcer treatment and recurrence prevention; age ≥4 weeks.
Product label / source ↗References & review status
Clinical reference updated October 16, 2026. Independent veterinary or veterinary-pharmacy review not yet completed. Evidence gaps remain explicitly identified; this page does not claim equivalence to a comprehensive, professionally reviewed veterinary formulary.