Objective: To evaluate the pharmacokinetics and clinical efficacy of budesonide in dogs with inflammatory bowel disease (IBD). Animals: 11 dogs (mean ± SD age, 5.7 ± 3.9 years; various breeds and body weights) with moderate or severe IBD. Procedures: Each dog received a controlled-release formulation of budesonide (3 mg/m2, PO, q 24 h) for 30 days (first day of administration was day 1). The concentration of budesonide and its metabolite (16-α-hydroxyprednisolone) was measured via liquid chromatography–tandem mass spectrometry in plasma and urine samples obtained on days 1 and 8 of treatment. On those days, plasma samples were obtained before the daily budesonide administration and 0.5, 1, 2, 4, and 7 hours after drug administration, whereas urine samples were obtained after collection of the last blood sample. A clinical evaluation was performed on the dogs before onset of drug administration and on days 20 and 30 after start of drug administration. Results: The highest plasma concentration of budesonide and 16-α-hydroxyprednisolone on day 1 was detected at 1 hour and at 2 hours after drug administration, respectively. After standardization on the basis of specific gravity, the ratio between urinary concentrations of budesonide and 16-α-hydroxyprednisolone was 0.006 and 0.012 on days 1 and 8, respectively. The clinical response was adequate in 8 of 11 dogs. Conclusions and Clinical Relevance: Budesonide was rapidly absorbed and metabolized in dogs with IBD. The drug gradually accumulated, and there was an adequate therapeutic response and no adverse effects.

Oxidative stress is a key component in the immunosuppression of chronic kidney disease (CKD), and neutrophil function may be impaired by oxidative stress. To test the hypothesis that in uremic dogs with CKD, oxidative stress is increased and neutrophils become less viable and functional, 18 adult dogs with CKD were compared with 15 healthy adult dogs. Blood count and urinalysis were done, and the serum biochemical profile and plasma lipid peroxidation (measurement of thiobarbituric acid reactive substances) were determined with the use of commercial reagents. Plasma total antioxidant capacity (TAC) was measured with a spectrophotometer and commercial reagents, superoxide production with a hydroethidine probe, and the viability and apoptosis of neutrophils with capillary flow cytometry and the annexin V-PE system. The plasma concentrations of cholesterol (P = 0.0415), creatinine (P < 0.0001), and urea (P < 0.0001) were significantly greater in the uremic dogs than in the control dogs. The hematocrit (P = 0.0004), urine specific gravity (P = 0.015), and plasma lipid peroxidation (P < 0.0001) were significantly lower in the dogs that were in late stages of CKD than in the control group. Compared with those isolated from the control group, neutrophils isolated from the CKD group showed a higher rate of spontaneous (0.10 ± 0.05 versus 0.49 ± 0.09; P = 0.0033; median ± standard error of mean) and camptothecin-induced (18.53 ± 4.06 versus 44.67 ± 4.85; P = 0.0066) apoptosis and lower levels of superoxide production in the presence (1278.8 ± 372.8 versus 75.65 ± 86.6; P = 0.0022) and absence (135.29 ± 51.74 versus 41.29 ± 8.38; P = 0.0138) of phorbol-12-myristate-13-acetate stimulation. Thus, oxidative stress and acceleration of apoptosis occurs in dogs with CKD, the apoptosis diminishing the number of viable neutrophils and neutrophil superoxide production.

Objective—To determine the association between urine osmolality and specific gravity (USG) in dogs and to evaluate the effect of commonly measured urine solutes on that association. Animals—60 dogs evaluated by an internal medicine service. Procedures—From each dog, urine was obtained by cystocentesis and USG was determined with a refractometer. The sample was divided, and one aliquot was sent to a diagnostic laboratory for urinalysis and the other was frozen at −80°C until osmolality was determined. Urine samples were thawed and osmolality was measured in duplicate with a freezing-point depression osmometer. The correlation between mean urine osmolality and USG was determined; the effect of pH, proteinuria, glucosuria, ketonuria, bilirubinuria, and hemoglobinuria on this relationship was investigated with multiple regression analysis. Results—The Pearson correlation coefficient between urine osmolality and USG was 0.87. The final multivariable regression model for urine osmolality included USG and the presence of ketones; ketonuria had a small negative association with urine osmolality. Conclusions and Clinical Relevance—Results indicated a strong linear correlation between osmolality and USG in urine samples obtained from dogs with various pathological conditions, and ketonuria had a small negative effect on that correlation.