Pain medications are commonly used in horses, but some of them may be causing more gastrointestinal problems than previously thought.

The most common pain medications used are classified as non-steroidal anti-inflammatory drugs, or NSAIDs, for short. Popular NSAIDs prescribed for horses include butazolidan (known commonly as bute), flunixin meglumine (known as Banamine®), and firocoxib (Equioxx®).

Dr. Gaby van Galen, DVM, MSc, Ph.D., Dipl ECEIM, Dipl ECVECC, EBVS®, European Veterinary Specialist in Equine Internal Medicine, performed a study on 22 horses housed at her university’s hospital. These horses were not under observation for gastrointestinal issues. Some were treated with NSAIDs, and some were not. The horses were examined daily for signs of colic, depression, reduced appetite, and loose stool. Ultrasound exams, fecal occult blood testing, and serum chemistries were performed.

The study found that 40% of the NSAID-treated horses had thickening of the inner lining of the intestinal tract in the upper right section of the colon after just three days of NSAID treatment. Dr. van Galen says this indicates there was a buildup of edema, or fluid, in the wall of the intestine, and some of these horses seemed uncomfortable and had decreased appetite, depression, and loose stools.

These findings, along with blood testing and fecal occult blood testing, indicated these horses had mild colitis, while the untreated horses had none of these signs. The signs were mild, and it was not necessarily indicated to stop treatment, but it does show we need to be careful treating horses with bute and Banamine®, and we need to monitor them closely.

Some horse owners may feel that giving NSAIDs regularly to their horses does not cause any problems, but this study shows these drugs may be causing more problems than first realized. Use of these type of drugs is not risk-free, and it is important to use as little bute and Banamine ®, or other NSAIDs, as possible.

Consult with your veterinarian about NSAID use for your horse.