Sedating Your Horse

If your child threw temper tantrums in the classroom or fidgeted at the dentist office, would you allow him to be given a drug used to treat schizophrenics’ Of course not. Yet sometimes it happens to your horse, unnecessarily.

Ask what’s being injected into your horse and why.

Horses are large, strong animals capable of doing considerable damage. You don’t want to be in the way of a horse that is crazed by fear or pain and unable to react normally.

A horse that has to undergo a painful procedure ? like suturing a wound ? warrants enough sedation to allow the veterinarian to remain in control. A case also can be made for sedation for oral procedures that require the use of a mouth speculum since those can be dangerous to the horse or the handlers if the horse starts flinging his head.

But for simple procedures, like passing a stomach tube or a rectal exam, a twitch works perfectly well. That said, with veterinary procedures, there is one other consideration: Adequate experienced help. If the vet feels there is a safety issue, animal or human, you need to respect that.

Otherwise, day-to-day issues like clipping, braiding and shoeing are basically temper tantrums, yet many barns think nothing of giving the horse a tranquilizer.


Acepromazine is a phenothiazine drug, a class used in psychiatry to treat severe mental illness such as schizophrenia and psychosis. Like all drugs that impact mental activity, it alters brain chemicals called neurotransmitters. When you give the horse a tranquilizer, you’re not relaxing him. You?re messing with his brain chemistry.

And it doesn’t help training either. Several studies have found that these drugs interfere with learning and memory. If ace is used to teach a horse that braiding is actually mundane or that a jump standard doesn’t have a lion behind it, odds are the horse won?t remember what happened when under the influence of the drug.

Sedation is necessary for procedures that might otherwise be dangerous.

If you have a gelding, think twice before using ace at all. When sedated with ace, the penis will drop. Normally, this reverses as the drug wears off over a few hours. However, permanent paralysis can also develop, a condition called phimosis, and it’s a high price to pay.

Because of their effects on coordination, sedatives have no place when riding, as muscle function and balance are also affected.


Two other drugs used in barns are fluphenazine (brand Prolixin) and reserpine (generic). Both are made to treat agitated psychotic states, like schizophrenia and severe mania (bipolar).

Fluphenazine and reserpine have become popular because of their long duration of activity (30+ days after one dose). they’ve been suggested for everything from weaving to making horses more manageable when ridden. Before the advent of more sensitive drug tests, they were widely abused in performance-horse circles.

Their severity should be reason enough to avoid them, but adverse reactions include periods of extreme agitation alternating with stupor. I witnessed a horse going through a reserpine reaction many years ago, and the memory is still vivid. There was the alternating agitation and stupor, along with extreme hypersensitivity to touch.

Because no one involved with the horse would admit to a drug having been used (it was revealed privately later), the horse was scheduled for anesthesia for a spinal tap to check for encephalitis. The horse made a few violent attempts to get up after the brief anesthesia but was unable to do so even with assistance and was euthanized. He had shattered his pelvis into tiny pieces.

Bottom Line.

Think hard before you reach for a quick chemical fix. Take the time to correctly discipline and train your horse, or get help from someone who can. there’s a reason these drugs should only be administered by a veterinarian.

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