phenylbutazone | Horse Racing Free Tips

Sore Back? Skip The Bute

Horse owners have been known to take medications prescribed to the animals in their care, despite the possible dangers. While some anti-inflammatories, antibiotics, and dewormers may be the same in both human and equine medicine, but their formulations can be vastly different; because of this, human ingestion of equine drugs isn't recommended.

An American woman experiencing severe back pain attempted to take some phenylbutazone (Bute) that had been prescribed for one of the horses in her care. She took three doses of the non-steroidal anti-inflammatory drug (NSAID), each suitable for a 400-pound horse, reports the journal Clinics and Practice.

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Three days later, the woman went to the hospital complaining of nausea, vomiting and weakness, which she said she had been experiencing for two weeks. She often had back pain that was controlled by use of over-the-counter naproxen, but reported that this episode was exceptionally painful, which is why she ingested the Bute.

She presented to the hospital with nearly low blood pressure, a high heart rate, and normal O2 levels, as well as dry mucous membranes. Blood work showed a low white blood count, low platelet levels, elevated liver enzymes, and acute kidney injury. Her urine blood screen showed use of amphetamines and marijuana.

Poison control and toxicology were engaged once it was discovered she had ingested the Bute, but no antidote was recommended. She was given an N-acetyl cysteine and sodium bicarbonate drip because of the suspected acute liver damage caused by the phenylbutazone.

After three days of in-hospital treatment, the woman was feeling better and checked herself out.

Though phenylbutazone was used in human medicine for the treatment of multiple forms of arthritis, it was removed from the human medicinal arsenal in 1970 because of an increased risk of agranulocytosis, a life-threatening blood disorder.

Bute: More Isn’t Better, It Can Be Dangerous

Phenylbutazone (“bute”) should have a place in every horse owner's first-aid arsenal to fight pain. However, if a traditional dose is given and the horse finds no relief, research says owners should reach for a different medication, not just administer additional doses of bute.

To test this theory, Dr. Ronald Erkert of Oklahoma State University conducted a recent study using three different pain treatment protocols on nine horses that were chronically lame in a front leg; each protocol lasted for four days. One group had injectable bute administered at two grams per 1,000 pounds. The second group had four grams per 1,000 pounds of bute injected. The third group received a saline injection to serve as a control. Before each injection and at six, 12 and 24 hours after the final dose, the horses were given a lameness exam and trotted on a force plate.

Erkert found no difference in lameness scores whether the horse was given two grams of bute or four grams of bute per 1,000 pounds. Erkert said that though his study was on injectable bute, administering additional grams of oral bute also has no significant benefit. Four grams of bute per 1,000 pounds approaches near-toxic levels. Bute toxicity can show up as diarrhea, gastric ulcers, colic, kidney failure and endotoxic shock.

Erkert recommends owners who give a horse bute and see no significant change in the horse's comfort level consult with their veterinarian to find a different pain control drug rather than administering more bute.

Study: Omeprazole And Bute Not Necessarily A Good Combination

Omeprazole is often prescribed to horses that are receiving phenylbutazone in an effort to reduce the chances of a horse developing equine gastric ulcer syndrome (EGUS), though it isn't clear how safe or effective this treatment is.

Drs. Megan Ricord, Frank Andrews, Francisco Yñiguez, Michael Keowen, Frank Garza Jr., Linda Paul, Ann Chapman and Heidi Banse created a study to evaluate the effect of omeprazole on adult horses with EGUS caused by phenylbutazone.

The research team used 22 horses that had equine glandular gastric disease (EGGD) and equine squamous gastric disease (ESGD), each horse had a score of a 2 or higher when tested for the disease. The horses were divided into three groups: one group (eight horses) received 4.4 mg/kg of oral phenylbutazone every 12 hours; the second group (eight horses) received the same phenylbutazone dose plus 4 mg/kg of oral omeprazole every 24 hours. The control group (six horses) received neither phenylbutazone or omeprazole.

The horses were treated for 14 days and had their stomachs scoped at days seven and 14. Blood tests were done at the beginning and end of the study period. Five of the horses did not complete the study because of intestinal issues (two in the phenylbutazone-only group and three in the phenylbutazone/omeprazole group).

The scientists found that the EGGD score increased in the study group that received the phenylbutazone only when compared to the horses that also received omeprazole. They found no difference in the ESGD scores between the two groups. Strikingly, six of the eight horses in the phenylbutazone/omeprazole group developed intestinal complications—two of which were fatal. Only two of the horses in the phenylbutazone-only group had intestinal complications, and neither of them died.

The team concluded that using omeprazole reduced the severity of EGGD, but that caution should be exercized when using the two concurrently, especially when this takes place at the same time as a management change.

Read the study here.

New Jersey Harness Trainers Cry Foul Over Change In Bute Rules

Harness trainers in New Jersey say they didn't receive proper warning about a rule change pushing withdrawal timeframes for phenylbutazone from 24 to 48 hours pre-race. According to a report from Harnesslink, a cluster of harness trainers have gotten overages for bute but they say the Standardbred Breeders and Owners of New Jersey was never notified of the rule change.

The state's harness horsemen say that Thoroughbred horsemen did receive proper notice of the rule change.

The New Jersey Racing Commission's website has not posted any new proposed rules since 2019, although it does provide an option for the public to sign up to receive email notifications of new proposed rules and rule adoptions.

First offense for a bute overage now includes a $500 fine, loss of purse and up to a 15-day suspension from racing.

One trainer questioned why, if he had been properly noticed of the change, he would have permitted his veterinarian to administer the non-steroidal anti-inflammatory inside the prohibited window.