Equioxx and Temperament?

Just curious if anyone else has noticed a change in temperament with Equioxx? I have a TB who’s been on it for the past 2 years. He’s always been known as a kind of an arse with attitude and I have just learned to ride through it, though it has been frustrating at times. Unless the moon and stars aligned JUST right, getting him into some sort of work mode was a challenge. Easily distracted, likes to argue, tantrums after about 20 minutes. He’s on Pentosan, so I let his equioxx run out about 3 weeks ago. 2 weeks ago was when I started noticing the change. He was so calm, relaxed and just easy to ride. Eyes just as soft as can be. The day the vet came and dropped off more, we’d had one of our best rides. I hadn’t changed anything else, but was seriously thinking, “Who is this horse??” No fussing, no arguments, fully listening and trying to give what I asked. No lookiness, no tantrums. Just easy peasy, pumpkin squeezy. This was 3 days ago. Vet came after our ride, gave me the Equioxx and I started him on it again that evening. Today, as soon as he came in for breakfast, I knew the arse was back. The soft, sweet eyes were gone. He snorted when I came in to fly spray him. He snorted at the boots I put on every time we ride. Still, I wanted to test it in the saddle. Not even remotely the same horse I rode 2 days prior. Looky and distracted. I’m pulling it again as I think he does well enough on the Pentosan alone, but I’m wondering if anyone else has noticed this change with the Equioxx?

I’d be wondering about ulcers (?) caused by Equioxx.


I’ve seen something about it causing ulcers in the mouth? He’s never had gut ulcers though. He’s on 24/7 turnout in a big lush pasture with only one other horse and gets a blend of orchard/alfalfa/timothy with feedings or during bad weather when he needs to be stalled.

As someone who had stomach ulcers… ulcers hurt and make you really pissy. I would be highly suspecting ulcers.

The acting out is not a new behavior. The relaxed, easy going calm is a new behavior. Trust me. I’ve owned this horse since he was 3, know him inside and out. He’s seen regularly by vet, chiro and massage. If it was ulcers, they wouldn’t magically go away untreated just from stopping the equioxx? I’m not asking him to be diagnosed. I’m asking if anyone has seen this type of change coming off or going on equioxx.

I did just search the forum and find another poster who said they had 3 horses get silly on Equioxx.

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Excitability is one side effect that was noticed in the trials for Equioxx. I had one that became a spooking monster on it. But I suppose if they are not a spooky type then other expressions of agitation could happen.

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If you remove the trigger the ulcers feel better.

While I could see a horse acting silly or getting more energy while on the equioxx, you are also saying he was this way before being on the equioxx. I’d chalk it up to a coincidence. Or ulcers.


That’s kinda what it feels like. He doesn’t spook so much as just be distracted and looking around, not wanting to participate, or easily excitable. For the few weeks he was off of it, he became more and more relaxed and focused.

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I know it’s not ulcers. But like I said, I’m taking him back off it, so I guess I’ll know once it’s out of his system again, if it’s indeed the equioxx.

How do you know it’s not ulcers? I only ask because my mare has plenty of access to forage and is known as the barn vacumn because she is ALWAYS eating, and she still had ulcers on Equioxx. If you’ve scoped and have definitive proof that’s not the issue, fair enough, but I wouldn’t rule it out just because.


Because I’ve had this horse since he was 3. I’m there every single day to care for him. Vet was just here in May for an exam. I’m giving you a brief summary of his behavior, not specifics, and maybe I worded it wrong or I don’t know how to describe it. When he hurts, he spooks at everything. I know instantly something is wrong, and it could be something as small as his saddle sliding back an inch. I have to get off and fix it and then he’ll go on like nothing happened. He’s jumpy and resistant. This is different. He’s distracted. Looky, not spooky. If something hurts, he will 100% not cooperate. It’s not an unmanageable behavior and because he’s been on it for 2 years, I just assumed that was who he was. He’s never been super laid back, but he has also matured a lot, so I was wondering if that is who he really is when he’s not on the equioxx.

Same as my old guy. He’s the barn vacuum and an air fern. But still developed ulcers on equioxx.


Even with the best diet and management, diligent vet care, etc. NSAIDs like Equioxx are known to cause ulcers, especially with long term use. Unless he scoped clean before stopping the Equioxx, there is absolutely no way to definitively rule out ulcers.

If removing the Equioxx caused that remarkable a change in behavior, I’d bet my bottom dollar that he had ulcers. Removing the NSAID trigger may have been all it took.


Thank you DVM’s. Always good to know I have a place to get my horse diagnosed sight unseen for free. Appreciate it. :slight_smile:

If you come on the forum and ask about something medical, expect to get answers. We are not an echo chamber.


My post wasn’t intended to make you defensive. No one here is insinuating you don’t know your horse, just that you can’t physically see inside him and that what you’re describing is pretty indicative of a gut issue. Ulcers don’t necessarily cause unmanageable behavior, they certainly didn’t in my mare. She was just unwilling to work fully, distracted, and looky. I’m sorry it’s not the answer you want to hear. :woman_shrugging:t2:


Again, maybe my wording was wrong. I thought I asked “has anyone seen a temperament change with THEIR horse on or off equioxx”. Circle for me where I said, “Please tell me what’s wrong with my horse?” I’m sorry, I’m not one to rely on the internet for medical advice for a horse they can’t see, examine or assess when I have a very capable vet. If you took that as me looking for an echo chamber, that is your perception. I did get my question answered by other posters, one noting studies that back up my suspicion, so I’ll lean towards that if that’s okay with you.

OP I think there’s an old thread on this topic with more answers from personal experiences.


They can magically get a whole lot less uncomfortable by stopping equioxx.

My mare can tolerate 2 weeks treatment without sucralfate. If I have to keep her on it longer than that, I need to treat daily with sucralfate and can stop the sucralfate just a couple of days after the drug treatment. If the course of meds is under 2 weeks, her behaviour will not change and I don’t need to treat her guts at all.

No you don’t. Not without testing or by a good long chunk of time treating appropriately. A ridiculously large percentage of horses have ulcers and can ‘cope’ ok with no treatment. However, irritate them and they ‘flare’ and can cause crappy behaviour. Treat them or even just remove the irritant, and you can find yourself with a whole new horse.

JFC, a good vet is open to hearing anecdotal evidence. A lot of times it’s the type of anecdotal stuff you are reading here that leads to studies that confirm anecdotal findings by lay people. You can not want your horse to have ulcers with every fibre of your being. Doesn’t mean it is so.

I mean I look back less than 10 years and I had a Very Good Vet tell me that there’s no research to back up using sucralfate in horses and that it probably wouldn’t work. My own vet willingly prescribed it and we got really good results. Nowadays, it’s a known treatment.


Adding, that when the drug originally came out, we were told that it was unlikely to cause ulcers. We now know that that is not true. Fewer acute incidences than things like Bute and Banamine? Sure, but we know it does cause issues. The original word of drug manufacturers and even initial research and trials are not the word of god and are not set in stone.

This is such an important thing to remember when we’re looking at using drugs in horses. The package insert isn’t the entire story.