Omeprazole Alone Doesn’t Heal Equine Ulcers

It takes a special formulation to be most effective on this common horse health problem.

From AQHA Corporate Partner Merial

Omeprazole keeps your sidekick by your side, even when they’re dealing with ulcers. Journal photo

Omeprazole alone is an unstable molecule. Exposure to air or being in the presence of acid can render the molecule ineffective. Horses are grazers by nature, and their stomachs are lined with billions of acid-producing proton pumps, contributing to that acidic environment. These pumps generate acid 24 hours a day, seven days a week, and can produce up to 16 gallons in a single day. These pumps’ continuous function means acid can build up quickly and lead to stomach ulcers in as little as five days.1

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In order for the omeprazole to work, it has to travel through this acidic environment of the horse’s stomach and into the small intestine where it can be absorbed. That’s why omeprazole needs to be specially formulated to survive the acid.

With two out of three competitive horses affected,†,2 stomach ulcers are a problem that most horse owners and trainers will face. You need reliable preventive and treatment options.

ULCERGARD® (omeprazole) and GASTROGARD® (omeprazole): The Solutions to Equine Stomach Ulcers

Consider using ULCERGARD® (omeprazole) and GASTROGARD® (omeprazole). They are the only products proven and FDA-approved to prevent and treat equine stomach ulcers, respectively. Both are specially formulated to protect the active ingredient omeprazole so that it can carefully make its way through the stomach’s acidic environment to the small intestine for absorption. Once absorbed, omeprazole works to block the signal for acid production within the stomach’s proton pumps to decrease the amount of active pumps. This allows the stomach to heal itself. 

Stable Results for Your Horse’s Stomach

When it comes to treatment, you want dependable and safe products. That’s why Merial, the makers of ULCERGARD® (omeprazole) and GASTROGARD® (omeprazole), goes the extra mile to properly formulate omeprazole for maximum stability and efficiency.

In 2014, the FDA found unapproved products claiming to treat or prevent equine stomach ulcers had inconsistent and varying amounts of omeprazole.3 Additional studies have shown some products have as little as 27 percent,4 and some as much as 126 percent.5

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Additionally, when looking at compounded products over time, a 60-day study comparing five compounded pastes to GASTROGARD® (omeprazole) revealed compounded formulas started as low as 63 percent of labeled concentration on Day 0 and as low as 17 percent on Day 60,6 while GASTROGARD® (omeprazole) held stable throughout the study. In addition, these products are not formulated to withstand the acidic environment of the horse’s stomach.

Don’t let your horse become a statistic. Contact your veterinarian about ulcer prevention and treatment options. 


ULCERGARD can be used in horses that weigh at least 600 pounds. Safety in pregnant mares has not been determined. Click here to read the product label.

Caution: Safety of GASTROGARD in pregnant or lactating mares has not been determined.

®GASTROGARD and ULCERGARD are registered trademarks of Merial Limited.

©2016 Merial, Inc., Duluth, GA. All rights reserved. EQUIUGD1630 (10/16)

†Non-racing, competitive horses.

1McClure SR, Carithers DS, Gross SJ, Murray MJ. Gastric ulcer development in horses in a simulated show or training environment. J Am Vet Med Assoc. 2005;227(5):775-777.

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

3FDA Issues Warning Letters for Unapproved Omeprazole Drugs Marketed for Use in Horses. Available at: Accessed January 29, 2015.

4Data on file at Merial.

5Data on file at Merial.

6Stanley SD, Knych HK. Comparison of Pharmaceutical Equivalence for Commercially Available

Preparations of Omeprazole. AAEP Proceedings. 2011;57:63.