By Deborah Clark, BSPharm, RPh, PCCA Clinical Compounding Pharmacist

Many of the calls that I receive from PCCA member pharmacies deal with veterinary compounding and therapeutics. I like to get to know the people I regularly talk to, and if time allows, I will normally ask the pharmacist about their veterinary compounding business. I get responses that vary from, “It seems like every other call is from a veterinarian,” to “Well, it is not as busy as I want it to be — do you have any suggestions?”

Most veterinary compounders get customized medication prescriptions for smaller species, such as dogs, cats, ferrets, pocket pets, birds or reptiles. Depending on the area where your pharmacy is located, there may be the occasional call for a horse. Equine compounding seems to be an area that some compounders avoid due to lack of education. I have to admit, when you are not familiar with horses, they do seem quite intimidating to compound for. Think about it: A horse is a large animal. They usually weigh anywhere from 800 to 1,000 pounds, and sometimes more. How do I get a medication into a horse? What do I have to consider when compounding for horses? These are important questions, and in this article, I would like to address them and many other common challenges for compounding custom horse medication.

Key Factors in Compounding for Horses

What does the horse do?

Horses can have a variety of activities they are involved in, and many have an actual job. A lot of horses are competitive athletes. Many people know this from watching equine events during the Olympics. Horses are involved in what is known as Equestrian Sports. There are a variety of competitions that include, but are not limited to, show jumping, dressage, endurance riding and racing (barrel, flat, harness, steeplechase).

Horses can also have multiple jobs on a farm or ranch as well as in the city. Stock horses are trained to work with livestock and are characterized by their agility, power and speed. A few jobs they are used for on the ranch include herding cattle, roping calves and team penning. They are also members of the police force in many cities. Mounted police can handle situations where officers on foot or in a car would not be able to go. Horses are also used to pull sight-seeing carriages in cities to entertain tourists.

When choosing a medication therapy for an individual horse, the animal’s activities or job is an important consideration. If the horse is a competitor, you need to look at the guidelines that are set forth by the governing body of the sport in which they compete. The Association of Racing Commissioners International (RCI) and United States Equestrian Federation (USEF) have strict rules about which drugs or substances can be used as well as withdrawal times for certain ones that are allowed. Doping to enhance performance of a horse is a concern in these sports very similarly to human sports. Stimulants, pain relievers and relaxing agents are commonly employed to enhance performance or calm the horse to present better in a show. Sometimes veterinarians ask compounding pharmacists to provide these medications in a dosage form for a horse, so it is important to know the regulations. If you live outside of the United States, it would be good to familiarize yourself with the International Horse Sports Confederation (IHSC), which is the new joint governing body of equine sport (a cooperation between the Fédération Équestre Internationale (FEI) and the International Federation of Horseracing Authorities (IFHA)). Additionally, if you are dealing with a working horse, you do not want to use anything that may impair their ability to do their job.

What is the best dosage form for the horse?

Another important thing to consider is the best route of administration for the disease you are treating. Horses are fragile animals and can have myriad issues, especially with environmental changes or with improper care. You also do not want to choose a route of administration that may cause extra stress to the animal. This is where communication between the compounding pharmacist and owner is key. It is good practice when taking on a new veterinary patient in general to ask what dosage forms and flavors have been tried in the past that did not work. (To help with this, PCCA members can use our veterinary client intake form .) This will help avoid repeating the previously unsuccessful therapy. Also, keep in mind when choosing formulas that these medications are typically going to be stored and administered in a barn or stable. There is usually no refrigeration available, so formulas that have this storage requirement may not be the best option.

Also on The PCCA Blog: “ How to Get Started in Veterinary Compounding ”

Common Treatment Issues for Horses

Those Beautiful Eyes

Horses have large eyes that protrude from their head and are prone to injury because of their placement. They also produce copious amounts of tears that can wash out traditional ophthalmic medications. Many times, ophthalmic drops need to be compounded to a thicker consistency to prevent this.

Oral Medication for Horses

Horses are herbivores, and as such, their gastrointestinal system maintains a delicate balance of flora to keep their “fermentation tank” in optimal shape. When administering oral preparations to the horse, it is very important to keep this in mind. Anything that upsets this delicate balance should be avoided. Equine oral medications can be formulated as several options: pastes, powders to add to feed, oral suspensions and treats. (PCCA members with Clinical Services access can see examples of equine oral medication formulas in our database.)

Oils are not a normal part of a horse’s diet, and it is advisable to not use them as an oral vehicle in these patients. If a horse does not like a suspension, they cannot spit it out. If it is thin enough, though, they can easily expel it from their mouth by simply lowering their head and allowing it to run out of their mouth. If the suspension is thicker or sticky, they are going to ingest it. It is a good idea to make suspensions thicker because of this.

Volume is another thing to keep in mind if making an oral suspension for a horse; 24 mL is a good maximum limit. If the owner indicates no preference of flavor, then fenugreek, peppermint and cherry are a few common favorites of horses, so you can consider those. If you use a cherry flavor, make sure that it is artificial and not natural (such as our artificial cherry flavor ). Certain components of cherry can be toxic to horses. If horses ingest something that is toxic to them, they cannot vomit.

Skin Issues

Horses can also have dermatological issues. These issues can be precipitated by the season, environment or stress. Atopic dermatitis can occur in equine patients. Parasitic, bacterial and fungal infection of the skin can also affect horses. The size of the horse can make it difficult to administer topical medications to larger areas, but compounded sprays with the appropriate active pharmaceutical ingredients can help address this issue.

Wound Care

Wounds are very common for horses. Scrapes and abrasions can occur during everyday activities. Horses overdo everything, and healing is no exception. When recovering from wounds, horses form what is known as “proud flesh,” which is overgrown scar tissue that can protrude from the area. These can be very unattractive and is something most owners want to avoid. Compounders can use bases such as PCCA’s ZoSil ^® or PracaSil^®-Plus and add active pharmaceutical ingredients that may help address this issue. (PCCA members with Clinical Services access can find some examples of topical spray and gel formulas for horses in our database.)

Hooves

You may see a three-legged dog, but you will never see a three-legged horse. Horses’ legs and hooves are very important to their overall health. Horses can be prone to hoof issues, and this is a great area where the compounder can be a huge asset to the equine veterinarian. The farrier, or blacksmith, is also a great person to get to know regarding this. The compounder can make custom poultices or soaking solutions for the equine veterinarian to use to treat these problems.

Compounding for horses can be challenging; however, when compounders educate themselves and take the time to build relationships with equine professionals, the outcomes can be quite rewarding for the horses, their owners and compounding pharmacies.

Deborah Clark, BSPharm, RPh, is a Clinical Compounding Pharmacist at PCCA. She previously worked in two independent hybrid pharmacies in Charlotte, North Carolina, managing compounding operations. While there, she worked with a local veterinary specialty and emergency hospital providing compounded medications for challenging veterinary patients. She also worked with the Carolina Raptor Center and several smaller veterinary clinics in the Charlotte Metro area. Deborah’s compounding experience also includes hospice, hormone replacement therapy (HRT), pain management, wound care, sterile products and pediatrics. She is certified in medication therapy management, and she is an associate member of the Society of Veterinary Hospital Pharmacists.

Photo by Lola Delabays on Unsplash.

These statements are provided for educational purposes only. They have not been evaluated by the Food and Drug Administration, and are not to be interpreted as a promise, guarantee or claim of therapeutic efficacy or safety. The information contained herein is not intended to replace or substitute for conventional medical care, or encourage its abandonment.