Bismuth to Treat, Prevent Equine Stomach Ulcers?

Bismuth to Treat, Prevent Equine Stomach Ulcers?

In the case of horses with ulcers, the use of bismuth is not recommended.

Photo: Michael J. Murray, DVM, MS, Dipl. ACVIM

April Knudson, DVM, is an equine specialist with Merial Veterinary Services. She has a special interest in equine gastrointestinal health, infectious disease, and lameness. She holds a doctor of veterinary medicine from the University of California, Davis. Here, she answers a question about the use of bismuth subsalicylate in horses.

Q. I've heard of people giving bismuth subsalicylate, commonly known as the human product Pepto-Bismol, to their horses to help treat or prevent stomach ulcers. Does it work?

A. Bismuth subsalicylate is used in people to treat diarrhea and gastric distress such as nausea, indigestion and heartburn; however it is not labeled for use in any animal. In the case of horses with ulcers, the use of bismuth is not recommended.

Once in the gastrointestinal tract, bismuth subsalicylate can be converted to sodium subsalicylate, which can cause gastric irritation. Additionally, salicylates, like aspirin, decrease prostaglandin secretion, which can further damage an already compromised stomach lining. For these reasons, bismuth is contraindicated in horses.

The only products that have been proven to be effective for the prevention and treatment, respectively, of equine stomach ulcers are the omeprazole products marketed as UlcerGard and GastroGard. These drugs work by suppressing the amount of acid produced in a horse's stomach, which increases the pH, and promotes healing of existing ulcers as well as reducing the potential development of new ulcers.

In some ulcer treatment products currently being compounded or offered commercially, bismuth and omeprazole are combined. There is no scientific proof these drugs work together and there's actually reason to believe the combination of the two does not treat or prevent equine stomach ulcers. Omeprazole is highly unstable in any type of acidic environment, and bismuth is acidic, so omeprazole likely degrades rapidly when combined with bismuth.

Owners should also be wary of any product claiming to be a generic version or a compounded version of omeprazole. There is no generic version of omeprazole approved for use in horses in the United States. Additionally, studies have shown that compounded omeprazole products are less effective and often have great variations in the amount of active ingredient versus what the label claims.

For the prevention and prevention of equine stomach ulcers, UlcerGard and GastroGard, respectively, are the only FDA-approved and proven products. Omeprazole is an inherently unstable drug, and both of these products contain a formulation proven to protect the active ingredient so that it will work to prevent or treat stomach ulcers in horses.

The key phrase for horse owners to look for when choosing an ulcer treatment or prevention product is "FDA-approved." When a product has been approved by the FDA, it has been tested for safety and effectiveness in the target animal, manufactured according to Good Manufacturing Practices in facilities that meet FDA guidelines, and is labeled and advertised in such a way as to not be misleading. To determine whether a drug has been FDA approved, horse owners should look for the six-digit New Animal Drug Application number, or in the case of generics, the Abbreviated New Animal Drug Application number on the label. Or, look up the drug in the searchable database at AnimalDrugs@FDA.

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