A quick guide to gastric acid suppression in dogs and cats

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The same drugs you may reach for yourself to relieve the gastric effects of too much stress can be used in your veterinary patients. Here's some guidance on acid suppressant usage given by Katie Tolbert, DVM, PhD, DACVIM, an assistant professor at the University of Tennessee's College of Veterinary Medicine, during a recent CVC.

First, skip the antacids, which aren't as effective as decreasing gastric acid for a prolonged period. Instead go for acid suppressants. Two types are generally used in veterinary patients:

• Proton-pump inhibitors (PPIs) such as omeprazole, pantoprazole and esomeprazole.

• Histamine type-2 receptor antagonists (H2RAs) such as famotidine and ranitidine.

Administration advice

• PPIs are most effective when taken before a meal. Tolbert recommends giving them 30 minutes before breakfast.

• H2RAs can be taken with or without food.

• Patients may become tolerant of an H2RA's effects after several days of receiving the drug.

• Don't combine PPIs and H2RAs if you're looking to reduce acid, says Tolbert. Even though they may take a day or two to reach full effect, PPIs are just as effective as H2RA on day 1. However, in cases of nocturnal acid reflux, you can use the two drug types together (PPIs in the morning and H2RAs in night).

Prophylactic pointers

One big question: Should acid suppressants be given to patients considered at risk for gastrointestinal ulcers that might need transient therapy? Let's look at several scenarios:

1. Perioperative gastroesophageal reflux: Tolbert says this condition is common in dogs (10 to 55 percent), a little less so in cats (2 to 12 percent). One study showed that 30 percent of gastrointestinally healthy dogs undergoing orthopedic surgery had perioperative reflux.1 In that study, the dogs benefitted from esomeprazole plus cisapride.

2. Kidney disease: Veterinarians often prescribe famotidine in patients with kidney disease, but Tolbert questions if they should be. Studies have shown no evidence of mucosal erosion or ulceration in patients with chronic kidney disease.2 And these patients are already receiving plenty of drugs, so why add to the burden? On top of this, PPI administration in people has been associated with a higher risk of kidney disease.3 Overall, further study is needed to define utility in patients with renal issues.

3. Liver disease: Although liver disease is one of the most common factors predisposing dogs to GI ulcers, Tolbert says there are so many other factors involved in ulcer development that acid suppressors may not be efficacious in these patients. In fact, a recent study shows that dogs with portosystemic shunts had significantly lower serum gastrin than healthy dogs.4 But Tolbert says the study did not look into whether or not these dogs had ulcers. Her best plan of action? Reserve PPI use for patients with evidence of GI bleeding such as melena, iron-deficiency anemia, and regenerative anemia in the absence of hemolysis. One important note: Avoid cimetidine, says Tolbert, as it has been associated with acute liver injury in people and is not an effective acid suppressant in dogs.

4. Pancreatitis: The effects of PPIs in people have been mixed-some studies have shown that PPIs may cause pancreatitis while others say they help reduce inflammation associated with it-so there is no definitive answer here. If a patient isn't having persistent vomiting, there's no need to administer a gastric acid suppressant, says Tolbert.

References

1. Zacuto AC, Marks SL, Osborn J, et al. The influence of esomeprazole and cisapride on gastroesophageal reflux during anesthesia in dogs. J Vet Intern Med 2012;26:518-525.

2. McLeland SM, Lunn KF, Duncan CG, et al. Relationship among serum creatinine, serum gastrin, calcium-phosphorus product, and uremic gastropathy in cats with chronic kidney disease. J Vet Intern Med 2014;28:827-837.

3. Lazarus B, Chen Y, Wilson FP, et al. Proton pump inhibitor use and the risk of chronic kidney disease. JAMA Intern Med 2016;176:238-246.

4. Mazaki-Tovi M, Segev G, Yas-Natan E, et al. Serum gastrin concentrations in dogs with liver disorders. Vet Rec 2012;171:19.