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Answers to questions about preventing equine stomach ulcers



How common are equine stomach ulcers?

Equine stomach ulcers have been found in horses of a wide variety of breeds, disciplines and ages, including:

  • 93% of racehorses1

  • 63% of nonracing performance horses2

  • 51% of foals3

Gastroscopy events at veterinary clinics and university campuses in 25 states identified stomach ulcers in a surprising number of horses.4 To see prevalence results by discipline, click here.


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What is EGUS?

EGUS stands for Equine Gastric Ulcer Syndrome, another name for equine stomach ulcers. It is used by some horse care professionals much like its human counterpart, GERD (which stands for gastroesophaeal reflux disease). Both are funny-sounding names that stand for serious clinical conditions. Click here for more information about EGUS.


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What causes EGUS?

EGUS is caused by excess acid that can eat through the stomach’s protective lining. Once present, stomach ulcers cause pain and reduce appetite, which can lead to even greater ulceration and damage. For more information about EGUS, the horse’s stomach and stress factors that can cause equine stomach ulcers, click here.


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How can I tell if my horse has EGUS?

Horses with stomach ulcers often do not exhibit any obvious clinical signs, and horse owners often do not know that their horses are suffering in silence.


Only your veterinarian can accurately diagnose equine stomach ulcers or EGUS — but you can help by looking for changes in your horse and reporting them to your veterinarian. Here are a few things to look for:

  • Change in eating and drinking behavior5

  • Weight loss5

  • Change in attitude (for the worse)5

  • Recurrent colic5

  • Dull hair coat5

  • Less-than-optimal performance5

  • Foals may also grind their teeth or lay on their backs6

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Is there an effective treatment for equine stomach ulcers?

Yes. GASTROGARD® (omeprazole) is the first and only medication approved by the FDA to treat stomach ulcers in horses. Horse owners should be aware that other products are not FDA-approved nor have they been proven to treat ulcers in horses.7-9 This includes:

  • Human antacids (PEPTO BISMOL® and MAALOX® and equine versions such as GASTROLOX and NEIGH-LOX)

  • Compounded formulations of omeprazole, like ULCER STOP

  • Dietary supplements (Succeed)

  • Nutraceuticals

  • Histamine Receptor Antagonists or H2 Blockers (TAGAMET® and RANIDITINE)

While GASTROGARD is proven to significantly improve stomach ulcers by up to 99 percent in treated horses,10 tests with other anti-ulcer treatments resulted in no lower odds of moderate or severe ulceration than horses receiving no treatment.11


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Why is FDA approval important to veterinarians — and to my horse?

FDA approval of a medication is validation that it is proven to provide the desired results in the species for which it was intended. Specifically:

  • Assured quality, purity, potency and bioavailability12

  • Each unit is manufactured for therapeutic consistency12

  • Proven storage stability12

  • Safety and efficacy scientifically demonstrated12


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How does GASTROGARD treat equine stomach ulcers?

GASTROGARD acts at the source of acid production. Unlike other, non-approved products, which work for a short period of time by neutralizing acid within the stomach lumen or acting at the mucous barrier, GASTROGARD inhibits the proton pump that produces stomach acid.13 For more information about the stomach acid cycle, click here.


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Can my horse continue training during treatment with GASTROGARD?

Yes.There is no need to interrupt training while treating equine stomach ulcers with GASTROGARD.14


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When should I use GASTROGARD?

After a horse has been diagnosed by a veterinarian, treatment with GASTROGARD® (omeprazole) for 28-days is recommended. GASTROGARD is the only product proven to treat existing stomach ulcers and the only one that is also FDA-approved.


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After using GASTROGARD, will my horse remain free of stomach ulcers/EGUS?

Following successful treatment with GASTROGARD, stomach ulcers can recur — in as little as 5 days.15


Your veterinarian may discuss stress factors that can lead to recurrence, and may tell you about the benefits of a preventive regimen with ULCERGARD® (omeprazole).


Click here to learn more about ULCERGARD.
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Where can I buy GASTROGARD?

Since the use of GASTROGARD requires a professional diagnosis for responsible use, it is only available as a prescription from your veterinarian.


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Important safety information:


CAUTION: Safety of GASTROGARD in pregnant or lactating mares has not been determined. ULCERGARD can be used in horses that weigh at least 600 pounds. Safety in pregnant mares has not been determined.


For prescription information for GASTROGARD, click here.


®GASTROGARD and ULCERGARD are registered trademarks of the AstraZeneca Group of Companies. All other brands are the property of their respective holders.


1Murray MJ, Schusser GF, Pipers FS, Gross SJ. Factors associated with gastric lesions in thoroughbred racehorses. Equine Vet J 1996;28:368-374.

2Mitchell RD. Prevalence of gastric ulcers in hunter/jumper and dressage horses evaluated for poor performance. Association for Equine Sports Medicine September 2001.

3Murray MJ. Endoscopic appearance of gastric lesions in foals: 94 cases (1987-1988). JAVMA 1989;195(8):1135-1141.

4Data on file at Merial.

5Equine Gastric Ulcer Council. Recommendations for the diagnosis and treatment of Equine Gastric Ulcer Syndrome (EGUS). Equine Vet Educ 1999;11:262-272.

6Murray MJ. Diagnosing and treating gastric ulcers in foals and horses. Vet Med 1991;820-827.

7Forward Research telephone survey of performance horse owners; commissioned for Merial. 2003.

8Murray, MJ. Suppression of gastric acidity in horses. JAVMA 1997:211(1)37-40.

9Nieto, JE, et al. Comparison of omeprazole and cimetidine in healing of gastric ulcers and prevention of recurrence in horses. Equine Vet Educ 2001;18:260-264.

10Freedom of Information summary for GASTROGARD Oral Paste.

11Orsini J, et al. Odds of moderate or severe gastric ulceration in racehorses receiving antiulcer medications. JAVMA 2003;223(3)336-339.

12Animal Health Institute and American Veterinary Medical Association and American Veterinary Distributors Association. Veterinary Compounding Guidelines. 2005. Available at:

http://www.aaep.org/pdfs/drug_compounding_guidelines.pdf. Accessed February 20, 2010.

13Equine Gastric Ulcer Council. Recommendations for the diagnosis and treatment of Equine Gasgric Ulcer Syndrome (EGUS). Equine Vet Educ 1999;11:262-272.

14GASTROGARD product label.

15McClure SR, Carithers DS, Gross SJ, Murray MJ. Gastric ulcer development in horses in a simulated show or training environment. JAVMA 2005;227(50:775-777.


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Photography by David R. Stoecklein

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