Efficacy of Oral Famotidine and 2 Omeprazole Formulations for the Control of Intragastric pH in Dogs

Background: Little is known about the efficacy of commonly used acid suppressants on intragastric pH in dogs. Objective: To compare the effect of oral famotidine, 2 formulations of omeprazole, and placebo on intragastric pH in dogs with a catheter‐free, continuous pH monitoring system. Animals: Six healthy adult mixed‐breed colony dogs. Methods: Utilizing a randomized, 4‐way cross over, open‐label study, dogs were administered famotidine PO (1.0–1.3 mg/kg q12h), omeprazole tablet (1.5–2.6 mg/kg q24h), omeprazole reformulated paste (RP) (Gastrogard, 1.5–2.6 mg/kg q24h), and placebo for 7 days followed by a 10‐day washout period. Radiotelemetric pH capsules were placed with gastroscopy assistance to continuously record intragastric pH for 4 days (days 4–7 of dosing). The percentage of time that intragastric pH was ≥3 and ≥4 was compared among treatment groups using repeated measures of analysis of variance. Tukey's Studentized range test was used to determine which groups were different with α= 0.05. Results: Mean ± SD percent time intragastric pH was ≥3 and ≥4 was 22 ± 8% and 14 ± 6% for famotidine, 63 ± 14% and 52 ± 17% for omeprazole tablet, 54 ± 17% and 44 ± 18% for omeprazole RP, and 6 ± 6% and 5 ± 5% for placebo. Both omeprazole formulations significantly increased intragastric pH compared with famotidine and placebo, but omeprazole tablet and RP was not significantly different from each other. Conclusion: Oral omeprazole tablet and RP provide superior gastric acid suppression to famotidine, and should therefore be considered more effective for the treatment of acid related disorders in dogs.