The frequency of oral famotidine administration influences its effect on gastric pH in cats over time

• Published in: Journal of veterinary internal medicine 2019-03, Vol.33 (2), p.544-550
• Main Authors: Golly, Elizabeth, Odunayo, Adesola, Daves, Maggie, Vose, Julie, Price, Josh, Hecht, Silke, Steiner, Joerg M., Hillsman, Shanna, Tolbert, M. Katherine
• Format: Article
• Language: English
• Subjects: acid suppressant; Acids; Administration, Oral; Anesthesia; Animals; Anti-Ulcer Agents - administration & dosage; Anti-Ulcer Agents - pharmacology; Blood tests; Cats; Cats - metabolism; Chronic illnesses; Cross-Over Studies; Crossovers; Drug Administration Schedule - veterinary; Famotidine; Famotidine - administration & dosage; Famotidine - pharmacology; Feces; feline; Female; Food; Gastric Acid - metabolism; Gastric Acidity Determination - veterinary; Gastrin; H2RA; Hydrogen-Ion Concentration - drug effects; Laboratory animals; Male; Oral administration; Random Allocation; SMALL ANIMAL; Studies; tolerance; Variance analysis; Veterinary medicine
• ISSN: 0891-6640; 1939-1676
• DOI: 10.1111/jvim.15430

Background Famotidine is commonly administered to cats. Prolonged famotidine administration results in decreased efficacy in humans, dogs, and cows, but the long‐term effects in cats are unknown. Objectives To compare the effect of 2 oral administration frequencies of famotidine, twice daily (Group 1) and twice daily every second day (Group 2), on intragastric pH and serum gastrin concentrations in cats. We hypothesized a diminished effect on intragastric pH would be observed over time in Group 1 but not Group 2. Animals Sixteen healthy cats. Methods Randomized, 2‐factor repeated measures crossover design. Cats received 0.5‐1.24 mg/kg (median, 0.87 mg/kg) famotidine twice daily or twice daily every second day for 14 consecutive days. Intragastric pH monitoring was used to record intragastric pH on treatment days 1‐3 and 11‐13. Mean pH and mean percentage time (MPT) intragastric pH was ≥3 and 4 were compared between and within treatment groups by analysis of variance. Results Significant treatment group by time interactions were observed for mean intragastric pH, MPT intragastric pH ≥3 and 4 (P = .009, P = .02, P = .005, respectively). Interaction post hoc tests identified significant decreases in mean intragastric pH (P = .001), MPT ≥3 (P = .001), and MPT ≥4 (P = .001) on day 13 compared to day 1 in Group 1 but not in Group 2. Conclusions and Clinical Importance Oral famotidine administration results in a diminished effect on intragastric pH in healthy cats when given twice daily every day.