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Reining horse possibly drugged with reserpine

Hi there. I’ll apologize in advance for the horribly long post, but in order to get adequate feedback, I feel that the details are needed.

Back in November, a close friend of mine traveled several states away to go look at a reining horse 2 weeks after a neutral party preformed a PPE on the mare. The vet called my friend and said she checks out but she was definitely a moody mare. Nothing too out of the ordinary or too much for said friend to handle. Said horse was supposedly shown extensively trail miles, the resume was insane and she bought this horse the right way. Said friend payed a pretty penny for this horse, registered AQHA, bred for futurity, you can tell by her bloodlines.
Fast forward 3 and a half weeks after the horse is bought and brought home. Friend’s other horse has gone lame and has a show, we throw new horse on the trailer and head to the show. I warm said friends horse up WTC, some rollbacks, a few stops and spins, leg yeilds, making sure she’s nice and ready for friend. Friend really enjoys riding but recently has had a lot of issues with her back and nerves with bulging discs etc, so I help her when I can. Friend rides horse and does great first 3 classes, first place, last class this horse blows up bucking, taking off out of nowhere. Friend and I were very confused. Took horse home, had her scoped for ulcers, nothing, saddle fitting, nothing, revetted, clean bill of health. Friend and I decided it was a fluke… since the time of blow up and investigation, friends health has declined and she now isn’t able to ride until after her surgery. I’ve taken responsibility for the horse’s care and exercise. I get on horse after 2 weeks off and she was a dream. Just like at the show, before the blow up. Ride her the next day and she was bucking, rearing, spooking at nothing. I didn’t think anything of it. Just lounging and riding her through it. She’s great one day, then pretty nasty the next. Today I get her out and go to lounge her for the first time in 3 days. It took 3 people to get this horse 10 feet from her pasture to the arena, she was barring teeth trying to bite. Got her in the arena and I’ve never in my life seen anything like this. She was running and sliding, then she’d run and slide to the point she fell. The barn manager made me leave the arena because he was concerned for my well being. Nightmare!

Friend tried this horse over the course of 3 days and she never put a good out of place. Her poop was runny, and they used shovels right under her while she was crosstied. You can’t move around this horse without her freaking out. She gets disciplined appropriately but I want someone’s perspective on this. I personally think she was drugged with reserpine. I could be wrong. I’ve never dealt with something like this. When my friend comes back from surgery, and is ready to ride, I know she will want to ride this horse. She doesn’t need to ride this horse, nobody needs to ride this horse.

What at are you thinking? I’m at a crossroads and don’t really know where to go from here. Thanks in advance!

sounds like a pain/ anxiety over anticipating pain thing. Check her back. KS perhaps? HYPP?


I don’t know why you are thinking reserpine. (Especially not with the first incident, where the mare was fine for the first half of the day and then unmanageable for the last class.)

The on-again, off-again aspect, especially with the fact that when she’s like this she loses all sense of her own well-being (falling) says to me this horse is experiencing some crazy pain.


It’s always easier to blame the seller than to look at the horse’s current environment, handling, riding, and tack fit.


She’s been vetted thoroughly. I just don’t know where the pain would be coming from. Our first thought was pain, that’s why we got a saddle fitted, got her vetted again, just to make sure she wasn’t in pain. We had flections, I’m just at a loss and was thinking maybe the drug has worn off and withdrawal has set in.

If your friend has back issues, that may prevent her from sitting a horse as well as she used to. If this horse happens to have a sensitive or weak back, those things may have caused back pain in the mare. I don’t know if the vet specifically and explicitly examined the back, or if you’ve tried NSAIDs for this horse, but in addition to those things, I’d probably be looking at some aggressive imaging of her spine.

I mean, I realize that you had the vet out and you thought about pain, but most of us have had the experience of going to a human doctor with clear symptoms and yet the doctor doesn’t know what’s wrong. I think that’s probably what you are dealing with here. There’s no test you can really do to be sure she isn’t in pain, unfortunately.


We’re not blaming the seller, we have reached out to the seller, asking for a phone call or to ask if she’s ever had issues with pain, or a bad back, and he has gone ghost along with his trainer. We’re not trying to blame anyone. We’re trying to figure out what’s wrong with this horse. Between the purchase, transport, saddle fittings, copious vetting, we are 25,000$ in the hole here and was just looking for a different perspective. Not negative hate.

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That’s a good thought… we had X rays done on her spine, but it couldn’t hurt to have ultrasounds done.

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Did you contact the seller and what did they have to say?
Maybe ask for permission to talk to the seller’s vet, unless you already did that, as most do with horses that are bought for the larger amounts.

If you suspected any drugging, did you immediately get some blood work done to rule that out, if still possible?
Some of those drugs have a longer half life.

I am not sure that Reserpine would mask that kind of behavior?

I don’t have any experience with drugs at all. So I don’t know it would mask such behavior. We reached out to the seller and sellers trainer, made successful contact with the trainer, Requesting prior vet documents. Her email reads “Unfortunaly I can’t release her records to you, try to contact -owners name-. He’s the only one that can release her vet records” which I understand, but friend who was connected to seller via Facebook noticed after reaching out, the sellers profile no longer appears, phone calls go directly to voicemail, trainer no longer responds. We just want to do right by this horse and this is not the life we would like to give to any horse.

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Personally, I’d let go of trying to bother with the seller. You may not be attempting to point any fingers but it’s unlikely you’d get much of an answer if they were to return your calls anyway. Either no, they’ve never witnessed this behaviour before with this mare, or yes, they have, and they don’t intend on telling you two that.

I’d go ahead with what other users have suggested. It may be costly, but some more extensive vet work may reveal the answer behind what’s going on with the mare whether it’s a physical ailment or a neurological one. I don’t imagine any drug last administered weeks previous would still have much or any influence on her behaviour, in the event she had been drugged prior to being sold.

If additional vet work reveals nothing, I’d look into perhaps getting a trusted trainer out for an assessment. They may be able to lend you some insight about what’s making her tick, so to speak. This may, unfortunately, just not be a fit for your friend in her condition. The horse may be fantastic on her “on” days and your friend may have sunk quite a chunk of money into her for the duration she’s had her, but if there’s no solution to the explosive behaviour, I just don’t imagine it’s worth it.


So much information! This article is absolutely wonderful! I will definitely be using this.


That they are avoiding you now, that does sound strange and maybe suspicious?

The reining world is small, everyone seems to know everyone else’s business, hard to pull something like that and stay in business long.

Keep asking around, see if someone has been showing where that mare did and if they knew of any problems?
Your trainer may know some people in that area that could help?


Have the vets considered an ovarian tumor? Those can make a mare act aggressive and cause pain that comes and goes.


Sounds possibly neurological? My gelding was like that when his (unknown to us) broken neck started to calcify into his spinal cord. One day he would be fine, and the next he would rear straight up when I tried to get on. He also became wildly (and randomly) aggressive to other horses.

It could also be drugs. Not sure if you can do any test now, but may be worth asking. Can they test hair for past use of drugs?

Another thought is could the mare by a hermaphrodite? That can cause very odd issues, and they may have been using drugs to keep her sane. I don’t think it is an expensive test.

I hope you figure the horse out.


My first thought was what Bagatelle suggested, tumors or cysts just purely based on my past experience.


I would definitely try to find out if anyone has seen this mare out and competing before. That may shed a lot of light on the subject - either she has a history of these kinds of outbursts, or this is brand new behavior. That can help you (and your vet) better understand the most likely causes.

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This was my first thought. Something to do with her ovaries.


I am assuming that a drug panel was not pulled at the PPE?

After going through a three month period of stall rest with my non-compliant TB, I think reserpine is absolutely a possibility. It does tend to give them diarrhea, and there are plenty of horror stories of horses being on reserpine for stall rest that are basically hallucinating when it starts to work out of their system. It also can increase the risk of ulcers, so it may be worth doing a trial of Ulcergard. IIRC you can’t show for 60 or 90 days after using Reserpine, so that should give you an idea of how long it can last in their system.

Also consider that it sounds like this horse has done a lot of sitting around since you brought it home. It might be the kind of horse that needs to be in a program 6 days a week, and your riding it every couple weeks is not going to work for it.