Horse getting hot / temperamental on Hydroxyzine (antihistamine)?

[sheltona01]

Hello, I am posting for my sister. Her pony is on Hydroxyzine and yesterday he was very hot / temperamental yesterday after she just put him back on it because of welts. He lunged for about 40 mins and never settled down. That is not normal for him especially in Texas in the summer. Has anyone else had this problem before?

Yes she is talking to her vet, but wanted to see if this has happened to other people. I am going to cross post between Off Course and Horse Care and she will probably chime in at some point. Just at work and cannot post right now.

TIA

[Gainer]

Two of my guys are on hydroxyzine from early spring through late fall. I’ve never had that sort of reaction from them; if anything, they’re a bit dull.

[Mhnij94]

I started my guy on this drug about a month ago…but I have not seen a difference in his personality or behavior at all…in fact, we started him on it in hopes it would help with a slight head shaking problem, but no avail. Oh, and we are in Texas also! I think there are various side effects associated with Hydroxyzine that can occur…would assume it’s different with every horse so maybe your sisters pony is sensitive to this particular drug…if she just started him on it and assuming it is causing the hot behavior, have her give it a bit of time to see if the kinks gets worked out, if they don’t go away or get worse, I would ask the vet about whether or not there are any alternative medications to try.

[PiaffeN_Passage]

Hydroxyzine in some horses will cause them to STOP sweating. So yes, he may be getting awfully hot if he can’t sweat. For most horses, it causes sedation.

I had a gelding on the top max dosage of 2,000 mg a DAY with no side effects. It also didn’t do a darn thing for him either in terms of his allergies.

[marogers01]

My horse also is on hydroxyzine from spring until fall, and he hasn’t had that reaction either. Could she perhaps lower the dose and see if that helps?

[horsepoor]

I’ve used hydroxyzine for allergies before and it was more sedating than anything. I did have it cause one horse to stop sweating, so I’m always very careful to monitor that if using any antihistamines. Now, I know with people, there can be some that antihistamines will cause to get anxious or wired rather than the “usual” sedation so maybe that could happen with horses? I also wonder if whatever is causing the welts is just making the horse more anxious, like if there are bugs really irritating him or just being uncomfortable from all the welts or whatever is making him not settle down.

[In1]

Hydroxyine is known in humans to cause drowsiness. With that said - I get hyped on it with horrific insomnia and mild tachycardia. Some people are weird with antihistamines - wouldn’t shock me to learn it may cause a similar reaction in some horses.

[FEIwannabe]

[QUOTE=PiaffeN’Passage;8722796]
Hydroxyzine in some horses will cause them to STOP sweating. So yes, he may be getting awfully hot if he can’t sweat. For most horses, it causes sedation.

I had a gelding on the top max dosage of 2,000 mg a DAY with no side effects. It also didn’t do a darn thing for him either in terms of his allergies.[/QUOTE]

My horse is on a powdered from of Hydroxyzine HCL that is compounded by a pharmacy in SC. The pill form didn’t work for him. Even when I crushed the pills, they were only marginally better. So maybe the format of the medication has something to do with it. It does with mine.

[sheltoneb]

Hi, this is the sister. I try to keep the dose as low as possible. The reason he had welts is that he was on the lowest dose and appeared to not be having issues with allergies, so I stopped giving it to him.

Once the welts appeared, I put him back on it to address the welts at twice the dose on Saturday. The welts are already gone.

I do think the medicine reduces his sweating. Therefore I monitor his sweating and try to kept the dose as low as possible. I also am careful about when and how long/intense the work is. I typically can see a clock, however when I was lunging I couldn’t track he time. Therefore I was just waiting for him to settle. He did get better, but did not completely calm down. I stopped specifically because it was hot and felt I wasn’t getting anywhere.

[jdobbs64]

I had better luck treating allergies with spirulina wafers- the hydroxizine made my horse dull and uncomfortable.

[PiaffeN_Passage]

[QUOTE=FEIwannabe;8723774]
My horse is on a powdered from of Hydroxyzine HCL that is compounded by a pharmacy in SC. The pill form didn’t work for him. Even when I crushed the pills, they were only marginally better. So maybe the format of the medication has something to do with it. It does with mine.[/QUOTE]

That is what he is currently on. Just like people what works as an allergy med for one person, won’t work as well for the next.