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

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.

Bartonella henselae, Bartonella koehlerae and Rickettsia rickettsii seroconversion and seroreversion in a dog with acute-onset fever, lameness, and lymphadenopathy followed by a protracted disease course.

Following recent tick exposure in Arkansas, a 2-year-old, female spayed Labradoodle was examined because of a one-week history of lethargy and shifting-leg lameness. The dog was febrile, had prominent lymph nodes, dull mentation, a stiff gait, and left forelimb lameness. Thrombocytopenia was the only initial hematological or biochemical abnormality. Despite treatment with doxycycline for suspected Rocky Mountain spotted fever, the dog continued to have waxing and waning clinical signs including inappetence, fever, shifting-leg lameness, lymphadenopathy, splenomegaly, and weight loss in association with moderate to severe hematological abnormalities, including anemia, thrombocytopenia, neutrophilia, and monocytosis. Sequential serological testing confirmed Bartonella henselae, Bartonella koehlerae and R. rickettsii seroconversion. Doxycycline, enrofloxacin and clarithromycin were administered in sequential combination for treatment of rickettsioses, B. henselae and B. koehlerae. Prednisone, thyroid supplementation and other drugs were administered to elicit symptomatic improvement. Based upon seroreversion, and the eventual resolution of all clinical and hematological abnormalities, therapeutic elimination of all three pathogens was seemingly achieved. Whether cortisol insufficiency due to adrenal exhaustion syndrome or post-infectious immune-mediated sequelae contributed to the symptoms and pathophysiological abnormalities reported in this dog was not determined, but are considerations for future cases.