If the thought of sedating your horse makes you nervous or uncomfortable, you’re not alone. Many horse owners feel anxious about the idea, but the truth is that sedatives are commonly used, safe and often easy to administer.
Veterinarian examining a horse.
Hearing the word “sedation” people think of a loss of consciousness, but sedatives that cause a loss of consciousness, referred to as general anesthetics, are reserved for equine surgical procedures.
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In many cases, sedation isn’t just helpful—it’s essential. Horses are powerful animals, and their size and fight-or-flight mentality can make for particularly dangerous situations for themselves and those around them if they’re startled, anxious, scared or uncomfortable. Additionally, there are parts of a horse that are not physically visible or accessible to a veterinarian, such as their teeth, unless the horse is sedated and relaxed.
When used appropriately, sedatives increase a horse’s comfort in stressful situations, helping to ensure your safety and that of the veterinarians and handlers working with them.
In this blog, I provide an overview of what horse owners need to know about sedation, including the different types of common sedatives and how they’re administered, when and why they’re used, what to expect during the process, and how to partner with your veterinarian to provide the best care and pain management for your horse.
Types of common equine sedatives and what to expect
When people hear the word “sedation” they tend to think of a loss of consciousness, likely due to medical procedures they or their family members have undergone. But sedatives that cause a loss of consciousness, referred to as general anesthetics, are reserved primarily for equine surgical procedures. The majority of equine sedatives do not cause a loss of consciousness but instead help the horse be more relaxed and less sensitive.
An easy-to-understand way to break down the types of sedatives is by their method of administration. Broadly, they can be organized into three categories:
1. Oral sedation
2. Standing injectable sedatives
3. General anesthesia
Oral sedation: Prescribed by veterinarians for horse owners to administer
The two most common drug types given by mouth for standing sedation are alpha-2 agonists and phenothiazines. They provide mild to moderate levels of sedation that help reduce a horse’s anxiety and awareness. The horse remains upright and conscious. Oral sedation typically takes longer to take effect since it needs to be absorbed through the gum tissue or intestinal tract into the circulatory system. The effects may last for an extended period of time, depending on the sedative type and dosage.
Acepromazine is a phenothiazine that works by blocking dopamine receptors in the horse’s central nervous system, which regulates alertness, resulting in moderate sedation. The effects of acepromazine can be variable depending on the horse and formulation, and it typically doesn’t result in as deep or long sedation as an alpha-2 agonist like Dormosedan® Gel (detomidine hydrochloride).
Dormosedan Gel acts by binding to alpha-2 adrenergic receptors, relaxing the muscles and reducing anxiety. Detomidine hydrochloride is the most potent alpha-2 agonist available for horses, meaning a little goes a long way. Dormosedan Gel is the first and only sedative approved by the FDA specifically for horse owner administration. It’s an oral mucosal gel administered under the tongue. Xylazine is another commonly used alpha-2 agonist that you might be familiar with. It’s sold both generically and under brand names like Rompun.
Oral sedatives like Dormosedan Gel have a wide range of uses cases, including the following:
• Routine care: Oral sedatives can make routine husbandry procedures less stressful for horses and handlers. Think sheath cleaning, bandage changing, clipping, mane pulling or corrective farrier work for a difficult situation.
• Fireworks: Fireworks and other loud, uncontrolled events can spook horses and lead to injury. Using light sedatives ahead of events like this helps ensure your horse stays calm, avoiding injury.
• Unfamiliar environments: Sedatives can help lower stress and anxiety and increase comfort in new environments. They can also promote positive reenforcement around activities like trailer loading, though horses should never be trailered when sedated without a veterinarian’s guidance.
• First turnout after injury: If your horse has been on stall rest after an injury, they may have pent-up energy they’re eager to expend. Sedation can help ensure they don’t reinjure themselves during those first few small paddock turnouts.
Standing intramuscular (IM) sedation: Administered by veterinarians
Typically, IM sedatives are given in the triangular muscular region in the neck, and usage requires knowledge of how to pull up the medication, where and how to insert the needle, how to administer the contents of the syringe (including aspiration to avoid blood vessels) and proper disposal of used materials.
The onset of action for an IM injection is quicker than for orally administered medications, taking 10 to 15 minutes. The duration of effect depends on the medication and dosage used. Your horse will go through similar stages as oral sedation as the sedative takes effect, as well as the same recovery process.
Standing intravenous (IV) sedation: Administered by veterinarians
Standing IV sedatives, which can have the same active ingredients as oral sedatives but a different formulation, are used when a more rapid onset of sedation is desired or higher levels of sedation or control are needed, such as for invasive medical procedures or examinations, dental care, or advanced diagnostics. IV-based solutions tend to go into effect very quickly once the drug is given, usually within 5 minutes.
The most common location for IV sedation is in the jugular vein, which sits on either side of the neck. Given the proximity of the carotid artery to the jugular vein and the potential for major complications, including seizure and death if the drug is inadvertently injected into the carotid artery, IV administration should be reserved for a veterinarian. Acepromazine, Rompun and and Dormosedan® Sterile Solution (detomidine hydrochloride) are examples of commonly used IV sedatives.
General anesthesia: Administered by veterinarians
Our last category, general anesthetics, includes the most powerful sedatives available. They’re also administered by IV for induction of anesthesia and may be maintained via a constant rate of infusion through an IV or by gas-inhaled anesthetics through an endotracheal tube using an anesthesia machine that can breathe for the horse. They’re always administered and monitored by a veterinarian and technician, and are usually required for advanced medical or surgical procedures where complete loss of consciousness is needed to complete the procedure, such as castration, colic surgery, arthroscopy, or fracture repair.
While a horse is under general anesthesia, their vital signs need to be continuously monitored through the end of the procedure and during recovery. Depending on the type of procedure performed, horses can recover on grass (like after routine castration), in a padded recovery stall (like after colic surgery), or in a sling or inflatable raft in a pool (like for neurologic or fracture repair cases) depending on the facility and availability.
Make informed choices with your veterinarian
Your veterinarian is always your best resource when it comes to equine health topics, including sedation. Don’t be afraid to be proactive and discuss your concerns by asking questions like:
• Will my horse need to be sedated during the exam or procedure?
• What type of sedative will be used, how does it work and how long will it last?
• How long until my horse can graze, eat or drink after being sedated?
• What’s the withdrawal period for the sedative (important for competing or racing horses)? You can also reference USEF/FEI withdrawal guidelines to ensure you’re following proper protocol.
See the complete blog on Equine Sedation - A Comprehensive Guide for Horse Owners
Press release by Zoetis - Blog by Jeff Hall, DVM, Managing Equine Technical Services Veterinarian, Zoetis