Individualized proton pump inhibitor therapy for canine gastrointestinal conditions

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In veterinary medicine, the use of proton pump inhibitors (PPIs) has become a standard approach for treating gastrointestinal (GI) issues such as ulceration, bleeding, and gastroesophageal reflux disease (GERD) in dogs and cats. However, determining the optimal dose and frequency of administration remains a challenge, especially for larger dogs. Veterinarians rely on human pharmacodynamic targets such as gastric pH due to the lack of canine-specific benchmarks. Although effective, PPIs like omeprazole and its isomer esomeprazole can cause adverse effects such as vomiting, diarrhea, and appetite loss, which can be challenging for pet owners, especially with larger dogs.

A study in the Journal of Veterinary Internal Medicine evaluated whether lower esomeprazole doses could achieve therapeutic pH goals while minimizing adverse effects. Investigators administered 0.5 mg/kg and 1 mg/kg doses once daily to 9 healthy, medium to large breed dogs. Intragastric pH capsules measured pH changes over 96 hours, with both doses significantly raising pH levels compared to baseline. However, one-third of the dogs did not meet therapeutic targets with once-daily dosing. For these dogs, twice-daily 1 mg/kg dosing successfully achieved the desired pH levels.

Despite promising results, the study highlighted significant variability in how individual dogs responded to esomeprazole. This variability was linked to factors such as differences in drug metabolism, inconsistent drug administration timing, and environmental influences like diet and housing conditions. For instance, cytochrome P450 enzyme activity probably played a role in affecting PPI metabolism, resulting in variations in intragastric pH responses. Given these factors, veterinarians should adopt a patient-specific approach when prescribing PPIs, especially for dogs that do not consistently respond to once-daily dosing.

Adverse events during the study occurred infrequently but followed a dose-dependent pattern. Only one dog experienced vomiting, which expelled the pH capsule shortly after administration. Diarrhea was more common, with the higher 1 mg/kg dose, affecting 3 dogs. In contrast, the lower dose (0.5 mg/kg) caused fewer GI effects, suggesting it could be a safer alternative for sensitive dogs. Reducing esomeprazole dosages may help minimize adverse effects without compromising efficacy for many dogs.

Both 0.5 mg/kg and 1 mg/kg doses of esomeprazole increased intragastric pH in healthy medium to large-breed dogs. However, the higher dose led to more GI adverse effects, highlighting a trade-off between efficacy and tolerability. Twice-daily dosing was essential for achieving therapeutic pH levels in non-responding dogs, underscoring the need for individualized treatment plans. Veterinarians must balance cost, efficacy, and side effects when prescribing esomeprazole, tailoring therapy to each dog’s unique needs and circumstances to provide more effective care for dogs with GI conditions.

Ava Landry is a 2026 PharmD candidate at the University of Connecticut in Storrs, where she is studying veterinary pharmacy.

Reference

Ostronic A, Gremillion C, Zhang S, Steiner JM, Tolbert MK, Gould EN. Pharmacodynamics of 2 dosages of orally administered esomeprazole in client-owned, healthy dogs: A prospective, crossover study. J Vet Intern Med. October 8, 2024. Accessed November 25, 2024. doi:10.1111/jvim.17233