Do Antacids for Horses Help Ulcers?

What are Antacids?

• There are many types of antacids, of varying chemical structures, that work to neutralize stomach acids. A common ingredient is calcium carbonate, similar to that found in TUMS and Rolaids.

• Antacids for horses are actually antacids for humans, and they work by reducing the acidity of stomach acid, thereby lowering the potential for irritation. These tablets or liquids only provide temporary relief.

• When fed, they may reduce signs of ulcers, but they won’t fix the primary cause. In fact, current science suggests that they may not have much effect at all.

Types of antacids

• Before you hit the pharmacy or grocery store to shop for your horse’s antacids, read this whole article and then talk to your vet. There is some science about antacids for horses, and there are SO MANY types and brand names that things get confusing.

Generic and brand names:

• Calcium carbonate is Tums or Rolaids.
• Magnesium hydroxide is Milk of Magnesia.
• Aluminium hydroxide is AtgernaGEL and Amphojel
• Aluminium and magnesium hydroxide are Maalox and Alamag
• Simethicone-based antacids are Mylanta, Almacone, and Gelusil
• Alginic acid is Gaviscon

How They Work

• Most antacids neutralize stomach acids. The dilemma with equines is that they are continuously producing acids.

• Some antacids, like simethicone, help reduce gas.

• Others, like alginic acid, create a foam hat on top of the stomach contents to help prevent gas from splashing around and hitting the upper portion of the stomach.

• But can antacids for horses help with ulcers? Maybe?

Overview of Equine Ulcers

• Ulcers are ubiquitous in the horse world, and depending on what study or factoid you read, anywhere from 20 to 90% of all equines have gastric ulcers, regardless of their age, breed, discipline, or lifestyle. The prevalence of these sores speaks to the challenges of keeping equines in domestic situations where they are not eating consistent, small amounts.

• There are two types of ulcers in horses: the gastric ulcers in the stomach and the hindgut ulcers further along the digestive system.

• Equine Gastric Ulcer Syndrome (EGUS) refers to ulcers in the esophagus, stomach, and the first part of the intestines, known as the duodenum.

• If the upper stomach area is affected, the ulcers and other diseases are included in the term Equine Squamous Gastric Disease (ESGD), also known as Equine Squamous Gastric Ulcer Syndrome (ESGUS).

• Even though equines can’t burp or vomit, they can still have stomach acid enter the esophagus via gastroesophageal reflux.

• Ulcers are graded on a scale of zero to four when visualized with a scope. Zero is the absence of ulcers, and four is severe ulcers.

• For the lower part of the stomach, ulcers are associated with Equine Glandular Gastric Disease (EGGD), also known as Equine Glandular Gastric Ulcer Syndrome (EGGUS). These lesions are difficult to detect and, therefore, lack a grading system.

• Gastric ulcers interfere with protein digestion, create pain, and the excess acid contributes to poor body condition.

Read this for some lovely photos of stomach ulcers.

Keeping hay moving through your horse is KEY to avoiding ulcers.

Causes of gastric ulcers in horses

• The primary reason for gastric ulcers is the upper part of the stomach getting splashed with stomach acids. The upper portion is covered in squamous cells, which do not protect against acids. Compare that to the lower portion, which does have a layer of cells that secrete mucous to safeguard against those acids.

• When horses have forage in their stomachs, the acids are working on digestion, and the food creates a physical barrier between the acids and the upper, unprotected area.

• When the stomach does not have food, which is quite often for domesticated horses, the acids are free to splash around, especially when the horse is active, like during exercise.

• Gastric ulcers in the horse’s stomach happen because the horse is consistently producing stomach acid! All the dang time! Horses need to eat constantly. Most horses don’t have this type of lifestyle, even with six feedings a day or more. For part of the day, your horse’s stomach fills with acid – without food. Hence, the acid gets frisky and does other things that it shouldn’t – like create ulcers.

• Contrary to human gastric ulcers, which have a bacterial component, there is no bacterial link to gastric ulcers in horses. 

• For ulcers in the protected area of the stomach, due to EGGUS, it’s suspected that NSAID use alters the stomach lining, and the usually protective mucus layer is less effective, creating an increased risk of lesions.

Diagnosis from a veterinarian

• While there are many signs your horse has ulcers, the only definitive diagnostics include gastroscopy or endoscopy, where your vet will sedate your horse and inspect the esophagus and stomach for ulcers. Then it’s on to medications and lifestyle changes to heal those sores.

Treatments for equine gastric ulcers – omeprazole

• Omeprazole PASTE is the gold standard for treating horses with ulcers. There is varying effectiveness of powdered and/or compounded omeprazole as it’s not as effective at surviving the stomach to enter the bloodstream and do its job of shutting down the acid-producing pumps.

• Results of a preliminary study comparing GastroGard (GG) omeprazole paste with Gastrozol (GZ), an enteric-coated omeprazole formulation, show that both help alleviate ulcers. However, GG is more effective at entering the bloodstream. This study did not look at compounded omeprazole.  

• QUOTE In conclusion, both omeprazole formulations used in this study, administered at the recommended oral doses of 4 mg/kg (GG) and 1 mg/kg (GZ) once daily and combined with appropriate changes in management and feeding, promote healing of mild‐to‐moderate gastric ulcers in horses. However, plasma omeprazole concentrations and AUC are significantly higher after GG administration.

Read the study here.

Omeprazole and rebound acid in horses

• Yes, horses can develop that surge of acid when omeprazole treatment stops abruptly. To combat this, taper the dose slowly with your vet’s help.

• Because omeprazole heals ulcers, it’s vastly different from antacids for horses, which simply change the pH. And because we don’t know the best dose and dosing interval, much less how long antacids should be fed, there are too many unknowns and opportunities for antacids to create complications.

• It’s only a best estimate that antacids work for about 4 hours, which leaves the overnight hours empty unless you can set up automatic feeding. With omeprazole, you can manage the rebound effects by tapering the dosage.

Read more about acid rebound here.

The gold standard for ulcer care.

Hindgut ulcers

• Ulcers in the colon are hindgut ulcers. And while gastric ulcers involve intense training and empty stomachs, hindgut ulcers are associated with long-term NSAID use, like bute and Banamine®.

• Other causes of hindgut ulceration include excessive intake of grain or sugar, such as from feeds and sugary grass. The hindgut microbes feast, and the resulting pH changes and buildup of lactic acid eliminate the healthy bacteria, causing hindgut acidosis.

• Stress is another factor contributing to hindgut ulcers, as are parasites that prefer to reside and reproduce in the hindgut of the digestive tract.

Antacids vs. Hindgut buffers

• Both antacids for horses and hindgut buffers work to neutralize acids in a horse’s digestive system, but antacids work in the stomach, and hindgut buffers work in the colon.

• For hindgut ulcers, treatment involves dietary changes, such as using slow feeders, a low-NSC diet, and grazing muzzles for pasture turnout. There are also prescription medications, such as sucralfate.

Evaluating the Efficacy of Antacid Supplements for Horses

• The thought behind using antacid tablets or liquids is that stomach acid changes the pH to a more comfortable level, thereby preventing or minimizing the exacerbation of ulcers. It’s largely anecdotal in terms of dosage, with many horse owners offering tablets before riding or exercising.

• What does science tell us about antacids for horses? Lots of things, including the obvious need for more research.

• There are also several questions, such as:

• What’s the dose for horse antacid tablets?
• How long do they last?
• Do they heal or prevent ulcers? Or neither?
• What about the rebound effect? This documented effect happens after you stop using antacids. After using an antacid, the stomach will produce more acid to counteract the neutralized acid, making the situation worse.

Scientific Evidence About Antacid Use in Horses

• Let’s examine several studies involving horses and antacids.

Famotidine, ranitidine, and magnesium hydroxide and aluminium hydroxide for horses

• This study examined the use of famotidine (Pepcid, Zantac 230) and ranitidine (Zantac) in combination with antacids. Famotidine and ranitidine are histamine blockers that reduce the amount of stomach acid. Famotidine and ranitidine address excessive stomach acid production, and not the acidity of the acid.

• Researchers found that the effects of famotidine and ranitidine in altering stomach acid pH were greater and longer-lasting than those of antacids.

The increase in gastric fluid pH was significantly greater for ranitidine (P<0.001) and famotidine (P<0.02) than for antacid. The duration of the effect was significantly longer for ranitidine doses (P<0.001) and nearly so for famotidine doses (P<0.055) than for antacid.

Read this study summary here.

Neigh-Lox for horses

• Kentucky Equine Research, a supplement company, published this paper detailing their research behind the Neigh-Lox antacid. They found that Neigh-Lox can be an effective antacid for equines.

Since its development, Neigh-Lox has been field tested in hundreds of horses. Many horses that displayed signs of gastric irritation such as poor appetite, chronic colic, and sour disposition have shown immediate improvement after receiving only a few doses of Neigh-Lox. Since there are no studies to show that Neigh-Lox heals ulcers, it is recommended only as adjunctive therapy to acid suppressive drugs in horses that have been positively diagnosed with gastric ulcers.

Read the paper here.

A small study about aluminum and magnesium hydroxide

• A small study of five horses revealed that antacids will alter the pH of stomach acid, but only for a short time. The implication (which needs to be studied further) is that this would require regular feeding every few hours for maximum effectiveness. But you still have the potential for the rebound effect should the dosing change or falter.

Oral administration of 30 g of aluminum hydroxide/15 g of magnesium hydroxide to adult horses should result in a mean hourly gastric pH ≥ 4.0 for at least 2 hours.

Read this brief here.

Antacids and cribbing

• Can you give your horse antacids to reduce cribbing? You can, but it may be a long-term project with limited results. Researchers studied this possibility and found that:

Although 21 d of antacid therapy significantly increased gastric pH in adult cribbing equines, it did not effectively reduce cribbing behavior in these horses. However, the significant carryover effect in the number of crib bites per day between periods indicates that a longer period of antacid therapy may be necessary to influence cribbing behavior in the adult horse.

Read the study here.

Therapies for ulcers

• This research indicates that antacids for horses must be administered (at an unknown dose, as this has not been determined yet) approximately every four hours, around the clock. That’s not great from a management standpoint.

• This paper also highlights the risk of rebound and notes that the use of antacids may interfere with the absorption of other medications.

Read this paper here.

Are TUMS for horses a good idea?

• TUMS may sound like a good idea, but it doesn’t work for preventing or treating ulcers. An effective dose is unknown. However, we do know that you need to dose every 4 hours, and that stopping dosing leads to rebounding acid production, often making things worse.

• Instead, rely on proven treatments to heal ulcers, and implement simple lifestyle and diet changes to help your horse.

Alternatives to Antacids for Horses

• The easiest thing you can do before a ride is to feed your horse forage. A “snack” of hay right before a ride creates that physical barrier in the stomach, preventing the splashing that sends acid from the lower portion of the stomach to the upper area that’s vulnerable to ulcer formation.

• Don’t rely on the flake you gave a few hours ago. The stomach is quick to send food along to the small intestine, which is why constant eating keeps the glandular region of the stomach busy digesting instead of ulcerating things.

• The most crucial treatment is changing the diet to a low NSC value, forage-first diet, and using slow feeders for all commercial, bagged feeds and hay products. You can find all manner of hay toys and feeders for pellets, cubes, and long-stem hay. There are also slow-feeding options for grains and pellets.

Slow feed, slow feed, slow feed.

How to feed instead of using antacids for horses

• Here are some dietary tips to help prevent the formation of new ulcers:

• Keep your horse chewing forage. A mix of alfalfa, with its acid-neutralizing calcium, mixed with other hays, is best.

• Pasture is great, too, if they can eat small volumes of grass slowly. Grazing muzzles help with this.

• Feed a low-starch and low-sugar diet. Don’t feed supplements with molasses or added sugars, and look for NSC values below 10-12% in hay and bagged feeds.

• Offer grains and concentrated feeds many times a day. Small meals are safer than one or two large ones.

• Consult with your veterinarian and equine nutritionist about your horse’s risk of ulcers.

• Make dietary changes over two weeks.

• Talk to your vet about your horse’s ulcer risk and hire an equine nutritionist to help you design a low-risk diet. Medications are not the only way to help your horse.

While antacids are one option to help your horse, there are more reliable and proven options. Your horse’s diet and lifestyle can have a significantly more profound impact on their digestive health than antacids for horses. If it’s the pre-ride buffer you are looking for, let your horse eat hay before a ride to create that floating hay hat in their stomach, and add alfalfa to their diet. Your veterinarian can help you with all of these changes.