Pharmacokinetics and pharmacodynamics of intravenous esomeprazole at 2 different dosages in dogs

BACKGROUND: Although the demand for esomeprazole is increasing in veterinary medicine, the pharmacokinetics (PK) and pharmacodynamics of esomeprazole have been described in only a few studies. OBJECTIVE: To determine the PK of 0.5 and 1 mg/kg esomeprazole administered IV q12h and to investigate its effects on intragastric pH in healthy dogs. ANIMALS: Six adult Beagles. METHODS: Open‐label, randomized, and crossover design. The dogs received 0.5 or 1 mg/kg esomeprazole IV q12h for 48 hours. Plasma concentrations of esomeprazole were measured by high‐performance liquid chromatography‐tandem mass spectrometry. Intragastric pH was determined using the Bravo pH monitoring system and recorded as mean percentage time (MPT) for which pH was ≥3 and ≥4 for 24 hours in each group. RESULTS: The peak plasma concentration and area under the curve from the time of dosing to the last measurable concentration in the 1 mg/kg group were higher than those in the 0.5 mg/kg group. However, when the dosage normalized, intergroup differences were not significant. The MPTs for which intragastric pH was ≥3 and ≥4 for 48 hours were 88% ± 7% and 81% ± 9% for the 0.5 mg/kg group and 90% ± 9% and 85% ± 11% for the 1 mg/kg group, respectively, with no significant intergroup differences. CONCLUSIONS AND CLINICAL IMPORTANCE: The pharmacokinetic parameters and acid suppressant effect for 0.5 and 1 mg/kg esomeprazole were not significantly different. Furthermore, the efficacy of esomeprazole 0.5 mg/kg IV q12h was sufficient to increase intragastric pH in Beagles.