I can’t explain much, I’ll leave that to more knowledgeable people.
I do know that horse people use this drug on horses, but I also think drug tests have included it for quite some time now. What puzzles me is not just how the drug would improve a shiverer, but what actually is the root cause of the shivering itself.
There has to be some proven mechanism that connects a treatment with a result, not just ‘well maybe’ or ‘perhaps it’s like this’. That’s what I’m missing here, something linking a cause of the disroder to a mechanism of a drug, but big time.
I did do some searches on the internet, and found that among some circles, this drug is indeed used simply to ‘take the edge off’ a misbehaving horse, one woman even recommended every horse that is gelded get it ‘while waiting for the testosterone to go away’. One vet even described two patients will ill effects that he believed were a result of giving this drug, one who ‘dog sat’ for long periods, and I believe a different case in which the horse kneeled on its knees for long periods of time. But with no research on horses, I’m not sure how one would know how much to give the animal or what the side effects might be.
Another vet site described side effects of pawing, sweating and odd tense movements of neck muscles.
One thing that would concern me is that as poorly as I know the drug class fluphenazine is in, I do believe a common side effect involves discomfort in heat and sunlight. I’d be uncomfortable working an animal and especially showing it, even if it needed this for a specific medical problem and it was allowed, until I was sure the animal would not be badly effected by sun and heat which is common at most competitions.
Side effects are often related to dose, with some drugs having fewer, milder and less frequent side effects with smaller doses (some medications that affect the nervous system or brain don’t have dose related side effects, though). So it seems for the good of the animal one would want to give as little of such medications as needed to be effective.
The worst thing I can think of is that if one injects the long acting form and it disagrees with the animal, you have 2 - 6 weeks wait for it to clear the system. Very rarely, there are extreme reactions to these drugs, even with a small dose. With a long acting drug I am afraid any unusual or rare reaction might be catastrophic.
Unless a drug like this really was proven to treat a specific disease that had to be treated, I would afraid to give it to a horse because from the little I know, there are no dose recommendations, side effects or effectivity research studies to work from. Perhaps this medication was recommended by a vet who had experience with many cases and can make some recommendations for dose and things to be careful of.
Outside of specific medical use, the ‘risk-benefit’ profile isn’t good and there are drugs with a better ‘risk benefit’ profile available. If it were a person with severe psychotic symptoms and a danger to self and others, it might be the only alternative if other drugs in its category don’t help, but with a horse, the situation is very different.
For behavior problems, I am uncomfortable giving a horse medication, I would prefer to handle such things with training, adjustments to diet and exercise. For emergencies, when an animal must stand for a painful emergency medical treatment, or lie quietly in an overturned trailer while waiting for assistance, there is good old ace.
