Bismuth subsalicylate is a gastrointestinal medication that may be prescribed for horses as a supportive therapy for diarrhea and intestinal irritation. Although widely available over-the-counter for human use, its use in horses is off-label and should only be administered under veterinary guidance. In horses, diarrhea and gastrointestinal upset can arise from a range of causes, including dietary changes, stress, infection, or inflammation. While bismuth subsalicylate may help reduce fluid loss and protect the intestinal lining, it does not address the underlying cause of disease and is typically used as part of a broader treatment plan.

Gastrobim® is a prescription omeprazole oral paste used in horses for the treatment of gastric ulcers and prevention of ulcer recurrence. Omeprazole reduces stomach acid, helping create conditions that support healing of ulcerated tissue in the stomach lining. Equine Gastric Ulcer Syndrome (EGUS) is highly prevalent in horses, particularly those exposed to intensive training, competition travel, stall confinement, and feeding practices that differ from natural grazing behavior. As a proton pump inhibitor, omeprazole suppresses gastric acid production. This makes Gastrobim® part of veterinary treatment plans for equine gastric ulcers, alongside management changes that address underlying risk factors.

Omeprazole is a cornerstone of managing gastric ulcers in horses, working to reduce stomach acid and promote healing. Equine Gastric Ulcer Syndrome (EGUS) is extremely common, particularly in performance horses exposed to intensive training, travel, and dietary challenges. In equine medicine, the most commonly used formulations of omeprazole are Gastrogard® and Ulcergard®. As a proton pump inhibitor, omeprazole works by suppressing acid production at its source, creating a more favorable environment for the stomach lining to heal. Available in formulations specifically designed for horses, omeprazole is widely used not only for treatment but also for prevention in high-risk situations such as competition, transport, or stall confinement.

Fluoxetine, commonly known by the trade name Prozac®, is a medication increasingly discussed in equine practice as an option for managing behavioral challenges in horses. As a selective serotonin reuptake inhibitor (SSRI), it works by increasing serotonin levels in the brain. Serotonin is an important neurotransmitter involved in mood regulation, stress response, and emotional stability. In horses, fluoxetine may be prescribed to address concerns such as stall rest anxiety, unexplained aggression, and stereotypic behaviors like cribbing or weaving. These conditions can be difficult to manage through training and environmental modification alone, particularly when they are deeply ingrained or linked to underlying neurochemical imbalance. In such cases, fluoxetine can serve as a valuable adjunct to a comprehensive behavior modification plan, helping to reduce reactivity and improve the horse’s ability to learn and adapt.

Hydroxyzine, sold under the brand name Vistaril®, is a first-generation antihistamine used in horses to reduce itching and inflammation caused by environmental and insect allergens. Unlike newer antihistamines, it crosses the blood–brain barrier, which means it can also cause drowsiness and sedation. Although hydroxyzine is not FDA approved for use in horses, it is commonly prescribed off-label in equine practice. It works by blocking histamine, a chemical involved in allergic reactions. Because hydroxyzine affects histamine receptors, it can interfere with diagnostic procedures such as intradermal allergy testing. For this reason, proper timing of administration is important when evaluating horses for allergic disease.

Domperidone, sold under the trade name Equidone® Gel, is a medication used in horses to support hormone balance and digestive function. It works by blocking dopamine, a neurotransmitter that supresses certain hormones, including prolactin. In equine practice, domperidone is most commonly used in pregnant mares to prevent or manage complications linked to fescue toxicosis. Beyond its role in reproductive management, domperidone has also been studied for its effects on gastrointestinal motility and blood flow in horses. These effects are related to its influence on dopamine-regulated processes throughout the body. Although domperidone was originally developed for use in humans, equine-approved formulations are available with a veterinary prescription. Unlike some similar drugs, it has limited penetration into the central nervous system, which influences its effectiveness and side effect profile.

Dexamethasone is a widely used corticosteroid in equine medicine, valued for its anti-inflammatory and immunosuppressive properties. Dexamethasone works by dampening the body's inflammatory response, providing rapid relief of clinical signs and improving overall comfort and function. Because of its strength and fast-acting nature, it is a common go-to medication in emergency situations and for management of chronic disease. Despite its effectiveness, dexamethasone use carries some risk in horses. Like all glucocorticoids, it can have significant side effects, particularly when used at high doses or over extended periods. Because of these considerations, dexamethasone should always be used under veterinary supervision, with careful attention to dosing, duration, and monitoring.