Psychotic reaction to Penicillin

Animagus

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One of my young horses was brought in by staff at the weekend whilst I was at Tweseldown with a few cuts and scrapes. One cut was a little deep and to be on the safe side they got the onsite vet to have a look, I agreed to let them treat her whichever way they thought necessary (thinking along the antibiotics route) as I was about to go XC and couldn't get hold of the owner to check. As it happens they decided to inject her with Penicillin.

I got a phone call half an hour later saying she'd had "the most horrific reaction" and had thrown herself repeatedly onto the concrete floor of the yard and lost control of her limbs, got her legs stuck under the vets car and then jumped onto the bonnet, galloped off down the road headfirst into a tree and then jumped a 6ft metal gate off a steep concrete hill onto the main road. I don't know what made that horse in such a state of panic who's brain was clearly not functioning normally stop and turn back around but someone was watching over when she did, she jumped back over the gate from a standstill but got caught on the top and opened her stifles, the skin on her stomach and must have fallen over after. She proceeded through a post and rail fence and was eventually caught once she came to a halt in the middle of a field.

I got a lift from a friend back in the car as we still had more horses to run that day so left early and turned up to find her in a real mess. The vets were stitching the skin joining her stomach and stifle back together and fitting it with a drain, she had skinned the other stifle completely, the vets said they'd never seen such a vast collection of wounds in one incident. She has no skin on her knees, hocks, cuts on her back, sides, two swollen black eyes, split lip....it would be quicker to list the places she hasn't hurt!

The witnesses said about 15 seconds after the injection she began to look startled as if she was staring at something in the distance. Then her legs buckled and she turned herself inside out. Why she was not injected in a stable I do not know, why she wasn't put on a course of Norodine fails me. I was told it was an "allergic" reaction which of course doesn't sit right, the classic allergic reaction is hives and irritation or in extreme cases anaphylactic shock in which case they stop breathing. This was neither. I think the procaine in the penicillin must have hit the bloodstream and gone to her brain which would produce a reaction similar to giving a horse a hit of cocaine or so I'm told.

The vet performed the injection and would have checked for blood in the needle but even if he saw none is it still possible he could have nicked a vein? What else would produce a reaction like this? It is a miracle nobody was killed or seriously injured and more amazing still that she is alive. It is going to be a long slow recovery for her and we X ray tomorrow to check for anything sinister under the massive swellings, she's being spa'd daily as luckily for her the yard has one 5 meters outside her stable and despite the pain she is in is showing incredible guts and enjoying the attention from everyone!

If anyone has experienced this or has any knowledge or advice do let me know, I had no idea this could even happen until it happened to me!
 
I'd most definitely say it hit the bloodstream! No vet I know will ever inject penicillin without the horse being in a stable or small enclosed area just to be on the safe side as it is so easy to have one tiny bit of a miss aim with the needle.

I hope the horse makes a full recovery with no long term problems.
 
This happened one of our horses as well before we owned him. Also described as an allergic reaction and we were warned never to give him penicillin.
However, speaking to other vets since, they have suggested that it did sound like a reaction to penicillin getting into the bloodstream. (we still don't chance it though!!).

Apparently he was in the stable when he was injected, but blew out the door and continued on through a few fences. :( Thankfully he escaped without any major injury.

I'm so sorry to hear this has happened to your horse. :(

I've also heard it happening to another horse and all they could do was close the top and bottom doors of the stable and wait it out. Apparently it sounded like a tornado going on in there.
 
It isn't a reaction to the pencillin, but to the procaine which carries it and is well documented and not particularly rare. I know of a horse that was given a jab. Horse reared up, took off and ran straight into a tree. But it survived to tell the tale. Just be careful that EVERYONE knows it is never to be given penicillin under any circumstances. I've given a good few jabs over the years but have always checked first that the horse has had it before safely and will refuse if the answer is I don't know.
 
I've seen it twice and after the first time when the horse ran blind for over 4 miles in a straight line I would never allow a horse to be given it outside the stable. TBH your vet should know that.
 
This happened to me last summer. As you say OP, it is the procaine getting into the blood stream and essentially gives them a cocaine hit. My mare cut her knee joint badly and was put on penicillin, the first two injections went well but on day 3 she shifted a little during the and I must have nicked a vein after I aspirated as she lost her mind - eyes rolling, legs buckling, charging awfulness. Luckily the vet had warned me it could happen so I was somewhat prepared but it was still very scary. She was fine within a few minutes but will never be getting penicillin again.
 
I have had this happen too! My big horse just hurled himself around in a blind panic, very frightening as you can do nothing until they get over it!
 
thought that the reaction is due to the procaine but that it only happens when it goes direct in to the blood stream,

and yes even if the vet pulls back on the syringe and there is no blood when the plunger is pushed on the syringe to administer the meds it can drive the needle a fraction deeper-hitting a vein. its not uncommon but penicillin should not be administered by injection in an open space
 
Wow I did not know about this, you learn something new everyday! Can the reaction be less extreme? If so it would explain Doodle's reaction.
A few years ago we had an incident with a hedge :mad:, and so the vet gave her a penicillin shot in her bum. Now Doodle is an angel with the vet, stands for injections and is a darling to do. But when given the penicillin injection she then leapt in the air and bombed off (luckily we were in the stable but were lucky not to get caught by her), she calmed down almost instantly but I have always wondered about what caused (for her) such a big reaction?

Hope your horse recovers well, it sounds awful!

x x
 
My vet told me that the pencillin jab is quite painful for the horse because it is such a thick liquid so it should be injected slowly.
 
God, I never knew this. What do they inject it into then, a muscle? I assumed it was injected in to a vein but can't actually recall when this was done to my pony who turned out to be allergic, he just ended up shaking all over, came out in hives I think and basically just collapsed flat out in the field for hours. He wouldn't eat and exhibited colic like signs. It went on for a couple of days and wasn't nice but nothing like mentioned above!
 
Most horses react to penicillan and it isnt the drug that lills them its the injuries they sustain. I will not allow my horse to be given penicillan there are plenty of other ab's on the market that treat possible infections, such as gentamycin, crystopen. Do not let horse be treated with anymore and change the ab's. hope horse is okay i havent read all the threads.
 
God, I never knew this. What do they inject it into then, a muscle? I assumed it was injected in to a vein but can't actually recall when this was done to my pony who turned out to be allergic, he just ended up shaking all over, came out in hives I think and basically just collapsed flat out in the field for hours. He wouldn't eat and exhibited colic like signs. It went on for a couple of days and wasn't nice but nothing like mentioned above!

Yes, into the hindquarter muscle. There is a lovely flat area between just to the side of the point of the hip which is always used. You alternate each side too so that the soreness isn't concentrated on one side.
 
Most horses react to penicillan and it isnt the drug that lills them its the injuries they sustain. I will not allow my horse to be given penicillan there are plenty of other ab's on the market that treat possible infections, such as gentamycin, crystopen. Do not let horse be treated with anymore and change the ab's. hope horse is okay i havent read all the threads.

Most horses? I think that is a bit of an exaggeration! I personally only know of the one and I've jabbed 5 successfully and known at least 25 which haven't had problems with it.
 
Most horses? I think that is a bit of an exaggeration! I personally only know of the one and I've jabbed 5 successfully and known at least 25 which haven't had problems with it.

i agree a bit of an exaggeration,

ladyt25 yours does sound more like an allergic reaction to me
 
This happened to a friend's horse about 15 years ago. I was holding him while she did the injection. The first few injections had been fine but the last one he had a unbelievable reaction to, which ended up in me hanging on to him for dear life in the (small) stable yard we were on until all the gates were shut before having to let him go. He then proceeded to jump over three five barred gates and galloped to the end of the farm before stopping and allowing himself to be caught. The ferocity of his reaction was such that we both felt that if he had been in his stable he probably would have killed himself. I've never seen anything like it.
 
i agree a bit of an exaggeration,

ladyt25 yours does sound more like an allergic reaction to me

Yes, mine definitely had an allergic reaction. When we reported to the vet he was pretty surprised as he said allergic reactions are very very rare. He likened it to the horse feeling like he had a really bad hangover and essentially told us to monitor him, ensure he was still drinking and he should be ok. He was soo poorly and very sorry for himself though bless him. I understand if he ever had one again he could quite possibly suffer a worse reaction and it could be fatal.
 
I never knew this and will make a mental note to never allow penicillin to be injected into my pony.

I hope your horse recover OP. x
 
Yep witnessed this happening. Horse injected, broke free galloped off crashing through 5 bar gate unfortunately flattening YO who stood behind it trying to stop horse. Both in sorry state afterwards.
 
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