Drug profile

The FDA adverse-event record for Omeprazole

2,584 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Omeprazole. See the species affected, top reactions, and outcomes below.

2,584
adverse-event reports
8.0%
death-coded share
Horse
most-reported species
683
Lack of efficacy - NOS - top reaction
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Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
2,584
Total Reports
208
Deaths Reported
8.0%
Death Rate

Active Ingredients

Omeprazole

Administration Routes

OralUnknownTopicalIntravenousIntramuscularParenteralIntraocularOphthalmic

Species Affected

Horse 1,352
Dog 833
Unknown 328
Human 37
Cat 28
Pig 4
Cattle 1
Mule 1

Most Affected Breeds

Unknown 383
Quarter Horse 285
Horse (unknown) 235
Thoroughbred 232
Warmblood (unspecified) 159
Retriever - Labrador 126
Retriever - Golden 59
Arab 48
Paint 36
Shepherd Dog - German 34

Most Reported Reactions

Lack of efficacy - NOS 683
INEFFECTIVE, GASTRIC ULCER(S) 581
Vomiting 259
Partial lack of efficacy 209
Diarrhoea 184
Lethargy (see also Central nervous system depression in 'Neurological') 156
Anorexia 141
Death by euthanasia 140
Other abnormal test result NOS 131
Decreased appetite 105
Elevated alanine aminotransferase (ALT) 104
Lethargy (see also Central nervous system depression in Neurological) 97

Outcome Breakdown

Ongoing
798 (36.1%)
Outcome Unknown
717 (32.4%)
Recovered/Normal
475 (21.5%)
Euthanized
141 (6.4%)
Died
69 (3.1%)
Recovered with Sequela
12 (0.5%)

Omeprazole Adverse Event Insights

2,584 reports name Omeprazole; 208 recorded a death outcome (8.0% of reported events, not a population-level mortality rate). Active ingredient: Omeprazole. Administration routes: Oral, Unknown, Topical, Intravenous.

By species: Horse (1,352 reports), Dog (833 reports), Unknown (328 reports). By breed: Unknown (383), Quarter Horse (285), Horse (unknown) (235).

Leading clinical signs: Lack of efficacy - NOS (683), INEFFECTIVE, GASTRIC ULCER(S) (581), Vomiting (259), Partial lack of efficacy (209). Outcome, 2,212 coded reports: Ongoing leads at 36.1%.

Read these counts as reporting volume, not risk: per our methodology, a widely-prescribed drug will rack up more raw FDA reports in a given year than a rarely-used one at an identical true rate, so we recommend comparing within similar-exposure products rather than across the full 2025 catalog.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

Every figure on PlainBreed is rendered directly from FDA openFDA adverse event data, no number is typed in by an editor. This page draws directly on FDA openFDA data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.