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  Discussion on Adverse reaction to medication resulting in 2 fatalities
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New Member:
kyderby

Posted on Wednesday, Apr 16, 2014 - 3:34 am:

Recently, my beautiful, healthy 4 y/o gelding and a talented, healthy 3 y/o gelding belonging to another owner, both Thoroughbreds conditioning to go back to their race careers, were given a "compounded" form of Baycox paste as one horse had blood tested positive-low titer level, for "exposure" to EPM last June while at the racetrack & was treated with an EPM med referred to as the "Drench", tolerated well and continued in training. The younger gelding had displayed very subtle symptoms of possible EPM so the Vet had the manager also give the "compounded" form of Baycox paste and to the 4 y/o as well as the exercise rider had felt that both horses were a little "off" behind and evidently it has become a routine for trainers to give some form of EPM med's whether they test positive or not, as they say it sharpens them up in training or right before a race. Both horses had received this medicine from two other tubes of the paste the week before and tolerated well. The third time it was given, the "same" tube of paste was given to both horses, that was made at the same compounding pharmacy, appears to have caused the death of both horses. Within approx. 2.5 hours after the horses had been given the oral paste, both horses began to have identicle symptoms,violent seizures, various abnormal neurological symptoms, severe sweating, panicked behavior, both appeared to go blind, screaming & groaning, uncontrolled violent shaking, muscle twitching,throwing their heads back, sitting down like a dog, increased seizures, & both were trying to fill their mouths with stall bedding. The 4 y/o died a extremely violent death in the stall & the younger horse was able to make it to the hospital 10 min away from training farm but could not stand and quickly went into a coma and also died.He had such violent seizures it was also discovered that his entire pelvis had also been fractured during the violent seizures & adverse effects of the medication. Both horses had necropsies performed and both were free of disease and actually "negative" for EPM when spinal fluid was tested during necropsy. Still waiting for final report on toxicology of compounded medication or contaminants that may have been in it to cause such violent deaths to these two healthy, young Thoroughbreds. The only thing these two horses had in common was they both had a dose of the compounded Baycox from the same tube of paste. No other horses on the farm have had any issues before or since this traumatic and devastating ordeal. Neither myself or the other owner have ever had anything happen like this. Both horses are from stakes winning families and were conditioning to return back to racing end of May. The 4 y/o had been gelded last Nov and was given time off during the winter before condition training this spring. The younger horse had a hind sesamoid injury last Sept so he had been on layup and turnout until back to conditioning in Feb. CBC & labs were all within normal range on both in the past couple months & all vaccines & deworming up to date. The necropsy report stated that "toxicosis" has "not" been ruled out as a cause of death. Dr O, I would sincerely appreciate any thoughts or comments you may have, or any of the members, especially if anyone has ever experienced something like this. These horses suffered through a extremely violent & horrific death. The trainer & staff who were present are still traumatized as the horses seizures & other symptoms were so violent it was unsafe for anyone to try and do anything. The compounding pharmacy was contacted so they would be aware and given the lot & batch # on the medication tube. We were recently informed that although they do a lot of business in the equine industry, they have also had some violations with the FDA in the past. A Vet who see's some horses at this breeding & training farm had gotten the tubes of the compounded Baycox from the compounding pharmacy and sold it to the trainer & manager for their farm medical supply. To my knowledge, he has never seen or examined either horse until the day of this horrible tragedy. I own the entire family of this 4 y/o and the full siblings are multi stakes winners. I foaled and raised this beautiful horse and I'm having a extremely hard time dealing with such senseless death of two healthy horses and the worst is knowing the details of their suffering before they died. No horse or animal should have to go through something like that. This just occurred two weeks ago but I'm still so upset, as is the other owner, that it's difficult to talk about. We are still waiting on the toxicology of the medicine & tube but I have read that sometimes it comes back inconclusive or couldn't determine, etc. Is there some type of specialist for a case like this? Like maybe a forensics specialist? It won't bring the two horses back but could possibly prevent a tragedy like this from happening to someone elses much beloved horses and possibly bring about some closure at some point. I am also checking to see if an "adverse" medication report was actually filed with the FDA because I have a feeling that it wasn't for several reasons. I also called the diagnostic lab where the necropsies were being performed & requested some of the tail and mane of my gelding and they informed me that the Vet had to request it, (even though I'm paying for the necropsy). So, the Vet said when he called them to request it for me they told him "No" that they couldn't do that. I have had to have necropsies done for horses that were insured at the same diagnostic lab and they never refused to let me have some of the tail and mane. I don't quite know what to think about all of this.
Member:
mogedy

Posted on Wednesday, Apr 16, 2014 - 1:14 pm:

Very sorry you or anyone would have to go through all that. I have no answers for you, but would suggest you request to talk to a supervisor or manager in order to get mane and tail hairs, especially if you're sure it was done before. Persistence can pay off. Reading this I had to wonder whether there is any chance that someone maliciously poisoned these two? Although on the surface the compounded med may seem to be the only link, there is always a chance that could be a coincidence.
Member:
vickiann

Posted on Friday, Apr 18, 2014 - 8:24 am:

I am so sorry to hear of such a dreadful situation and hope that you get some answers.
Member:
gramsey1

Posted on Friday, Apr 18, 2014 - 10:55 am:

Gosh Anne,
My heart breaks to hear of the deaths of your horses. They sound like wonderful animals. This is a horrifying story. You have my sincere condolences. I am sure that there is nothing I can say to console you in this loss.

I gather from your post that you are looking for answers. Maybe it wasn't the Baycox, or the compounding pharmacy. But, it seems like a logical place to start.

A Google search "Baycox for Horses" brings up some articles. It appears this drug has been used by horse owners for many years. This article isn't too old.

https://www.epmhorse.org/Treatment/Treatment.htm

Do you know that Baycox is not FDA approved for horses? Yet, I found it for sale, apparently without prescription?!

https://horseprerace.com/toltrazuril(Compare-the-active-ingredient-of-Baycox%C2%AE)/toltrazuril-for-epm-200ml/

With this warning at the very bottom of the page.

"The only time I have heard of any reaction occurred when someone used the Toltrazuril 2.5% Poultry Concentrate by direct oral dosing in 3 day old piglets. This formulation is designed to be diluted in the drinking water for poultry. To be soluble in water, the product undiluted is very alkaline, pH 11.4. Direct oral dosing of the undiluted product is very irritating to mucous membranes and will cause immediate vomiting. Make sure you are using the correct formulation."

pH 11.4, Wow!! This would be really bad in an animal that cannot burp or vomit.

Again, let me express how terribly sorry I am to hear of your loss. We have to trust experts to help us choose what is best for our horses, to achieve our goals for our horses. I hope you learn that the advice you were given was sound. And that the cause of the deaths of your valued horses had nothing to do with the decision to treat them with Baycox.
Moderator:
DrO

Posted on Saturday, Apr 19, 2014 - 9:35 am:

Welcome Ann,
I am so sorry to hear about your horse's experience. There are few published studies on the toxicity of toltrazuril probably because in 2000 the medication was found to be reasonably safe in horses even at high doses.

Vet Ther. 2000 Fall;1(4):245-51.
A 10-day toxicity study of toltrazuril 5% suspension in the horse.
Furr MO1, Quance J, Kennedy T.

Equine protozoal myeloencephalitis (EPM) is a serious disorder of the nervous system of horses caused by Sarcocystis neurona. Recently, toltrazuril has begun to be used for treatment of EPM. The purpose of this study was to evaluate the potential toxicity of toltrazuril in horses when administered at a dose of 50 mg/kg for 10 days. Five horses were given 50 mg/kg of toltrazuril once daily for 10 days by nasogastric tube. Complete blood cell counts, serum chemistry values, and coagulation panels were evaluated before and after treatment; then a full postmortem examination was completed on day 11. Results of the study show that only mild clinical signs (i.e., anorexia, weight loss, and colic in one of the five horses) were observed after treatment. Minimal changes were noted in the serum chemistry analysis (i.e., increased bilirubin and serum protein, mildly increased hematocrit and hemoglobin concentration, and mildly increased albumin). Renal medullary congestion was noted on gross postmortem examination; however, no microscopic changes due to compound administration were noted in the kidneys or other tissue. Results of this study suggest that administration of toltrazuril at 50 mg/kg (5x to 10x anticipated clinical dosage) for 10 days resulted in only mild clinical abnormalities.

The timing and circumstances of the event make the paste suspect. As Guy notes above there are no formulations approved for horses and sometimes the formulation can be the problem. Was a incorrect amount of active ingredient present? Is there some toxic contaminant in the formulation? Is there some other factor that may have made the correct formulation more toxic? Or is this some huge coincidence and something else the cause? It seems we should be able to answer most of the questions following a thorough necropsy and evaluation of the product.

The importance of correctly answering these questions is both to help you understand what has happened but also in preventing future deaths. There are two aspects of preventing death: the cause of these horses' deaths and death from keeping a effective medication for a deadly disease from being used in a timely manner. Please keep us informed as to your progress.
DrO
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