There are certain things that you can hardly do with horses when they are they’re in full control of their energy.

You can’t shoe or clip horses when they are active. Horses don’t usually take it easy when you’re trailering them either. You also should expect some level of aggression if you’re having their teeth floated. For these reasons and more, equine sedation has become standard practice.

It is important to note that not all horses need sedation. Still, a sedative is a must before carrying out certain equine procedures. If you want to castrate a standing horse, you sure don’t want to do that without sedating him.

Why Do You Need To Sedate A Horse?

Some horses can be quite nervous and can’t relax. It can be dangerous for them and their owners to clip them. They can also harm a farrier who’s trying to shoe them.  In such a case, it is best to sedate them.

Some riders only feel safe when they have sedated their horses before riding even with their boots on. Of course, sedating a horse is not standard practice. Hardly any equestrian event allows that.

If you need to regain control of feral horses, it can be dangerous if you don’t sedate them.

To carry out certain operations on untrained horses, you also need to sedate them. Unhandled horses will not remain standing for operations if you haven’t sedated and anesthetized them.

You’re achieving something else if you sedate your horse before going for such processes. You’ll be building long-term confidence in your horse to endure or enjoy it. Dr. Polly Taylor is a specialist in equine anesthesia. She made a point that summarizes the need to sedate a horse in the following words. “Sedation can also be a nice way to show a horse that something isn’t as bad as [the horse] thinks.”

For instance, it will be appropriate to sedate a horse that had endured the pain of overheating. You will do the same if there’s the discomfort of blunt clipper blades. According to Dr. Taylor, sedating will be a way to tell the horse: “It won’t happen again: you often only need to do it a few times.”

It’s safe and advisable to use sedation in the short-term. If a horse has to remain standing during a surgical procedure, sedation will play a vital role. Dr. Taylor adds: “You can do a better job of stitching a leg wound, for example, if the horse is standing calmly and not trying to kick you.”

A horse sedative works by slowing down many of the nerve transmissions in its brain. Other common sedatives work in different ways. Some of them may block the transmission altogether. Whichever way it works, it boils down to the same thing: the suppression of the processes usually required for alertness in horses.

Quick Facts About Horse Sedation

How long will the horse remain sedated after you’ve administered the sedative? Generally, the effects of the drug will become noticeable soon after applied. The horse may remain sedated for about an hour. But there are several factors that affect the longevity of the effect on the horse. The type of drug, the dosage, and the health condition of the horse play a role. Some horses get over it after 30 minutes while others may remain stupefied for more than 90 minutes.

It takes as long as 30 minutes before you see the effect of some drugs. This can last up to eight hours or more.

There have only been a few cases of reported side effects of sedation. They are those usually connected with overdoses and intravenous doses. There is a measure of risk associated with an injection into the jugular vein, for instance. There are chances that it goes into the carotid artery. If this error occurs, the injection goes straight into the brain.

It’s not advisable to feed your horse close to the time of sedation. Choking is one of the side effects that can happen if you allow the horse to eat while sedated. Give a sedated horse a break of 2 to 4 hours after the sedation. It’s better if you can take the horse through a type of balancing bodywork after any procedure that requires sedation.

Sedating Horses Yourself Or By A Vet?

This depends on how you want to sedate your horses. There are three main ways to do this. Two of them are through an oral administration or an oral syringe. Domosedan and Sedalin/Relaquin are the sedatives used for this. Horse owners may administer this without much professional help.

The third way is to sedate the horse through an IV administration of the sedative. You would need to contract a vet to do this. Some of the drugs that veterinarians use are not available over the counter.

Intravenous Sedation

Intravenous sedation may be appropriate for some horses. It’s the type given through the vein by means of an injection. Oral sedation may not be enough if the procedure is complex. There can be other reasons to increase the dosage of sedation. In these cases and others, IV sedation is the way to go.

The dosage of intravenous sedation is usually higher. This and the type administered depend on some factors. Theses factors include the duration of sedation needed and the procedure that the vet or farrier intends to carry out.

Other factors include the depth of sedation needed for the procedure and the horse’s sensitivity to sedation.

Since the IV sedatives are prescription-only drugs, you need to visit a vet if you decide in favor of IV sedation. One more advantage of IV sedation is that it produces a much greater depth of sedation. No wonder, it is the one recommended for horses that are too sensitive to the operation you want to perform.

Visiting a vet also allows the sedation to be effective. For instance, a vet will wait for a while; maybe up to 15 minutes. This will let you know if the horse is coming around too early from sedation. Veterinarians know when to give a ‘top-up’ I/V sedation. Such equine sedation is generally a mixture of a horse sedative drug and an opioid. This will produce a more profound sedation, resulting in less sensitivity to touch.

It’s good to avoid tranquilizing a horse while sedating the horse. It’s this confusion that makes some horse owners take after Acepromazine (ACP). Many doctors have warned that ACP is only a tranquilizer and not a sedative. Dr. Taylor says: “ACP will stop a nervous horse being worried about something, but it won’t help if it’s trying to kill you!”

Downsides Of Sedation

Sedation involves major and minor risks. Consider, for instance, horses that have gone feral. The veterinarians actually need to dart them with sedatives. They don’t usually get close to them. Since they usually live in a herd on the range without chutes or fenced areas, this has a downside. It may take 15 to 30 minutes for sedatives to be effective. A sedated horse may go too far and encounter environmental hazards. The horse may be vulnerable to predators.

Darting is the way to sedate such horses since you don’t get too close to them. The dart may strike the horse in a wrong place with dire consequences. It won’t be funny to dart a horse in the chest, abdomen, eyes or other sensitive areas. Dr. Trish Dowling, a vet, and equine instructor, also acknowledges this problem. She says that if a drug is “given in the carotid artery rather than the jugular vein, it’s a bad wreck.”

In other domesticated horses, there are still reactionary issues. Side effects of common drugs used in sedating horses include:

  • Excess and prolonged salivating
  • Sweating and diarrhea
  • The blood glucose level may shoot up.
  • There can be decreased intestinal motility
  • There’s the risk of early labor if administered on a pregnant mare
  • If given during the last trimester, retention of the placenta is common

Horses that appear heavily sedated may respond to some external stimuli. Handlers need to exercise extra caution when handling sedated horses.

There are concerns about giving these drugs to horses with certain health problems. They are dangerous if a horse is showing signs of heart disease or respiratory dysfunction. Horses with seizure or those who are in shock are not fit for equine sedation.

There are reports of horses that faint after taking even minimal doses of sedatives. This happens because sedatives slow down heart rates.

Dr. Dowling mentioned earlier, identifies another challenge. “If the animal is already agitated or excited, it’s difficult for these drugs to work. They do also reduce normal inhibitions, so a horse that usually wouldn’t kick you may kick you when sedated.”

There are occasions when horse owners sedate their horse using human drugs. This is clearly against vet recommendation. Some of these drugs can have a long-lasting effect on the horse, running into four weeks or more. Dowling teased: “Now you can sell your ‘wingnut’ horse and [the horse] doesn’t show [the] true personality to the new owner for about a month.”

Other human medications may cause the horse to ‘freak out’ and react in a strange way. The horse may attempt to climb a stall wall or try to escape in an injurious way.

Sedation can take away certain natural processes in horses. Dr. Sid Gustafson is a veterinarian using the natural approach to equine treatment. He brings that to attention. He says: “In situations that involve pain, such as trauma or surgery, of course, sedatives and analgesics are very valuable. But it’s preferable for horses to be appropriately socialized, taught, desensitized, and prepared to handle most of the situations they’ll be expected to tolerate such as trailering, showing, riding, clipping and medicating.”

Some horses don’t need sedation. The issue is with the way the handlers are going about handling them. Katrina Merkies, a professor of Equine Management emphasizes. She teaches how to train a horse in a natural way. She says: “Horses are reactionary. They respond to the situation. Sometimes, you get a strong reaction because something scared or hurt the horse in the past, and to the horse this seems like a similar situation. If you can learn to read your horse, your horse will let you know what the problem is.”

How To Sedate A Horse

You can sedate a horse using either the phenothiazines or the alpha-2 adrenergic agonists (A2As). The phenothiazines are usually acepromazine and in the form of injection. They are also given as granules and added to feeds. They are not prescription drugs.

The alpha-2 adrenergic agonists are prescription medications. You can only get them from vets. It’s safer to have the vet administer the injection. A2As have an analgesic effect. So they are often recommended when carrying out a procedure that involves horse pain. They are part of the treatment of a horse with colic. The most often used and most effective A2A is Dormosedan Gel

Dormosedan Gel For Horse Sedation

An example of A2A is Dormosedan, which is one of the best out there. Its active ingredient is detomidine hydrochloride. The compound name of the chemical is 1H imidazole, 4-[(2,3-dimethylphenyl) methyl]-hydrochloride. It is stronger than acepromazine (ACP). It’s a white, crystalline, water-soluble substance indicated for sedation and restraint in horses. Each milligram of the gel contains 7.6 milligrams of detomidine hydrochloride.

Dormosedan Gel is unlike Sedalin that is a mere tranquilizer. It gives deeper and more effective sedation. So, it is the most effective for the horse that needs a medium level of sedation. You can administer Dormosedan gel on your horse with only a prescription from the vet.  It’s an oral administration.

Dormosedan administration: There is a little challenge in administering it. You don’t throw it into the horse’s mouth like a wormer which the horse will swallow right away. If a horse swallows it, it won’t be very effective. It must be under the tongue on the gum. The good thing is, there is a dosage syringe that delivers the gel in increments of 0.25 ml.

It also comes with impermeable gloves that you will use when handling the product. Allow at least 40 minutes to pass after administering it. You can then start the procedure. The sedative can last on horses for about 90 to 180 minutes.

Dormosedan dosage for analgesia: Though it’s not a pain reliever, it can work somehow in that range. Some horse owners are testifying to its analgesic effects. The manufacturers state that Dormosedan is not for analgesia. They also caution against its use for painful procedures.

Dormosedan dosage for sedation: This depends on the duration of the procedure and the targeted depth of the sedation. Veterinarians are in the best position to determine the appropriate dosage. Generally, bodyweight is the determinant of the dosage.

The table below can give you an idea of the dosage in relation to the body weight in pounds and kilograms.

Approximate body weight (in kilograms)

Approximate body weight (in pounds)

Range of doses (milligram / pound)

Range of doses (milligram /kilogram)

Dose volume (in milliliters)

150 – 199

330 – 439

0.023 – 0.017

0.051 – 0.038


200 – 249

440 – 549

0.022 – 0.017

0.047 – 0-038


250 – 299

550 – 659

0.021 – 0.017

0.046 – 0.038


300 – 349

660 – 769

0.020 – 0.017

0.044 – 0.038


350 – 399

770 – 879

0.019 – 0.017

0.043 – 0.038


400 – 449

880 – 989

0.019 – 0.017

0.043 – 0.038


450 – 499

990 – 1099

0.019 – 0.017

0.042 – 0.038


500 – 549

1100 – 1209

0.019 – 0.017

0.042 – 0.038


550 – 600

1210 – 1320

0.019 – 0.017

0.041 – 0.038



Dormosedan application process: Follow these simple steps in applying the gel into the horse’s mouth:

  • Remove the syringe from its outer carton.
  • Hold the plunger and its ring-stop in a way that you’ll be able to slide up and down the plunger with ease.
  • Check the horse’s mouth to be sure that there’s no feed.
  • Take out the cap from the syringe tip and keep the cap replacement.
  • Insert the syringe tip. Let it in from the side of the horse’s mouth. The syringe should be beneath the tongue around the level of the mouth commissure.
  • Depress the plunger to deposit the content beneath the tongue.

Warnings and contraindications: Do not give Dormosedan Gel to any horse with confirmed hypersensitivity to detomidine. It’s also not recommended for a horse with a history of atrioventricular (AV) or sino-atrial (SA) blocks. A horse with pre-existing respiratory disease or chronic renal failure also can’t use it.

It’s not for human consumption. Be careful when handling Dormosedan to avoid accidental ingestion. Though there’s no proof that it can cause any dermal absorption, it may cause skin irritation. So, clinical prudence is important. But absorption can occur if there’s direct exposure to eyes and mouth.