NSAIDs: Not All They're 'Stacked' Up To Be

Bute and Banamine are two of the most common non-steroidal anti-inflammatory drugs (NSAIDs) on the market, and they easily accessible to nearly every horse owner. They can be the first line of defense in emergency cases such as colic, and phenylbutazone (Bute) and flunixin meglumine (Banamine) are frequently stacked (given together) by owners, trainers, and veterinarians to treat lameness.

But researchers at the University of Missouri, Columbia, and Oregon State University said combining two or more NSAIDs can be a dangerous practice.

Nathaniel Messer, DVM, Dipl. ABVP, an associate professor of equine medicine and surgery at the University of Missouri, said although they are given together at their individual therapeutic dosages, stacking two or more NSAIDs can have toxic effects.

The study examined 24 adult horses in a double crossover study (horses were given a single NSAID, then later given a combination of Bute and Banamine). Study horses that were given stacked NSAIDs had a greater incidence of gastric ulcers and low protein levels secondary to ulceration.

"There was more prevalence of this in the group receiving stacked drugs than in the group receiving the regular dosages of a single drug," Messer explained. "We use them in therapeutic dosages by themselves, but by using them both at the same time the dose can become toxic to horses and can cause serious problems."

He added, "We had one horse that actually died in the study from severe gastrointestinal ulceration and colitis because of what we felt were the effects of stacking the two drugs. In extreme cases, you can get into some kidney or renal damage, but there was no evidence of that seen in our study."

Most veterinarians understand that combining high dosages of NSAIDs can be toxic. However, Messer said, "I have to think that the idea of stacking originally came from veterinarians."

The problem is that these types of drugs are readily available to horse owners, who, although possibly well-meaning, are unaware of the potential harmful effects that stacking can cause. Although the study only examined these two types of NSAIDs, Messer believes these results would hold true for any NSAID combination.

"It's the old misconception, if a little helps then more will be better," Messer said.

Researchers in the study published in the March 2006 issue of the American Journal of Veterinary Research were Messer; Shannon Reed, DVM; Ronald Tessman, DVM, MS; and Kevin Keegan, DVM, MS.

About the Author

Chad Mendell

Chad Mendell is the former Managing Editor for TheHorse.com .

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