Objectives The aims of this study were to determine the side effect frequency and serum and urine drug concentrations of amoxicillin–lavulanic acid in cats with and without azotemic chronic kidney disease (azCKD). Methods Owners whose cats had been prescribed amoxicillin–clavulanic acid completed a survey regarding the occurrence and type of side effects, and whether treatment was altered as a result. Cats were defined as azCKD (serum creatinine concentration >2.0 mg/dl, urine specific gravity [USG] <1.035 with a clinical diagnosis of CKD) and without azCKD (serum creatinine concentration <2.0 mg/dl). Data were assessed with Fisher’s exact test. Serum and urine samples were obtained from client-owned cats with azCKD (n = 6) and without azCKD (n = 6, serum creatinine concentration <1.8 mg/dl, USG >1.035) that were receiving amoxicillin–clavulanic acid. Amoxicillin and clavulanic acid were measured with liquid chromatography coupled to tandem mass spectrometry and compared between groups with a Mann–Whitney test. Correlation between serum creatinine and drug concentrations in urine and serum was determined using Spearman’s rank test. Results Sixty-one surveys were returned (11 azCKD cats and 50 without azCKD cats). No significant difference in the presence of side effects or type of side effects was seen between groups; however, significantly more azCKD cats had more than one side effect ( P = 0.02). More owners of azCKD cats reported that an alteration in treatment plan was necessitated by side effects (55% vs 12%; P = 0.008). Urine amoxicillin was significantly lower in cats with azCKD ( P = 0.01) and serum amoxicillin trended toward significance ( P = 0.07). Serum amoxicillin concentration was positively correlated with serum creatinine ( P = 0.02; r = 0.62) and urine amoxicillin concentration was negatively correlated with serum creatinine ( P = 0.01; r = –0.65). Conclusions and relevance The data suggest that cats with azCKD have altered pharmacokinetics of amoxicillin, which may contribute to an increased incidence of multiple side effects.

BackgroundLiver disease (LD) prolongs mirtazapine half‐life in humans, but it is unknown if this occurs in cats with LD and healthy cats.Hypothesis/ObjectivesTo determine pharmacokinetics of administered orally mirtazapine in vivo and in vitro (liver microsomes) in cats with LD and healthy cats.AnimalsEleven LD and 11 age‐matched control cats.MethodsCase‐control study. Serum was obtained 1 and 4 hours (22 cats) and 24 hours (14 cats) after oral administration of 1.88 mg mirtazapine. Mirtazapine concentrations were measured by liquid chromatography with tandem mass spectrometry. Drug exposure and half‐life were predicted using limited sampling modeling and estimated using noncompartmental methods. in vitro mirtazapine pharmacokinetics were assessed using liver microsomes from 3 LD cats and 4 cats without LD.ResultsThere was a significant difference in time to maximum serum concentration between LD cats and control cats (median [range]: 4 [1‐4] hours versus 1 [1‐4] hours; P = .03). The calculated half‐life of LD cats was significantly prolonged compared to controls (median [range]: 13.8 [7.9‐61.4] hours versus 7.4 [6.7‐9.1] hours; P < .002). Mirtazapine half‐life was correlated with ALT (P = .002; r = .76), ALP (P < .0001; r = .89), and total bilirubin (P = .0008; r = .81). The rate of loss of mirtazapine was significantly different between microsomes of LD cats (–0.0022 min−1, CI: −0.0050 to 0.00054 min−1) and cats without LD (0.01849 min−1, CI: −0.025 to −0.012 min−1; P = .002).Conclusions and Clinical ImportanceCats with LD might require less frequent administration of mirtazapine than normal cats.

Objectives The purpose of this study was to survey owners regarding their practices and experiences with the administration of subcutaneous (SC) fluids at home to cats with chronic kidney disease (CKD) to gain insight that might help more owners be successful with the procedure. Methods A web-based survey was advertised online. Owners of 468 cats with CKD participated, 399 of whom administered SC fluids. Results Fifty-nine percent of the cats were domestic shorthairs, with >85% of the cats being 10 years of age or older. IRIS stage 3 was most commonly represented (37%). Ninety-five percent of owners said they discussed giving fluids with their veterinarian, with only 42% of those discussions involving additional educational resources. A large majority of owners (85%) said it was either an easy, somewhat easy/no stress or okay experience for them, and a large majority (89%) reported that the experience was easy/no stress, somewhat easy or okay experience for their cats. To increase tolerance, 57% said they gave a treat to their cat afterwards, and 60% said they warmed the fluids. Sixty-one percent reported using a 20 G or larger needle, with 49% saying size of needle affected tolerance. Seventy-four percent also felt that the length of time it took to administer fluids affected tolerance. One-hundred milliliters was the most commonly given fluid amount. Hydration status was monitored by 40% of owners by various methods, with 40% of those saying they skipped or added fluids based on hydration assessment. Conclusions and relevance A majority of owners gave positive feedback about their ability to learn and administer SC fluids to their cat wth CKD. Owners reported several strategies that they felt improved tolerance of fluid administration. Overall, the protocol should be tailored to the preference of the cat for best possible long-term success.

Objectives The objective of this study was to assess the absorption of transdermal ondansetron in healthy cats. Methods Five research cats with unremarkable complete blood count, biochemistry and urinalysis were used for both single- and multiple-dose application studies. For single-dose application, 4 mg ondansetron in 0.1 ml Lipoderm gel was applied once to the internal ear pinna. Blood samples were collected via jugular catheter over a 48 h period following administration (0, 15 mins, 30 mins, 1 h, 2 h, 4 h, 8 h, 12 h, 24 h and 48 h). For multiple-dose application, 4 mg ondansetron in 0.1 ml Lipoderm gel was applied for five consecutive days before blood samples were obtained in the same manner. Serum was separated and frozen prior to analysis. Ondansetron was measured via liquid chromatography coupled to tandem mass spectrometry. Results Analysis revealed no clinically relevant drug levels in serum after either single- or multiple-dose administration of 4 mg transdermal ondansetron. Conclusions and relevance Transdermal application of 4 mg ondansetron does not result in clinically relevant serum concentrations of drug. Despite characteristics of the drug that imply suitability for transdermal application, this does not appear to be an acceptable method of drug delivery for this medication at this dose. This study highlights the importance of assessing the suitability of each medication for transdermal administration.

Objectives The aim of this study was to assess the effect of three oral potassium supplements (potassium gluconate tablets [PGT], potassium gluconate granules [PGG] and potassium citrate granules [PCG]) on hypokalemia and serum bicarbonate in cats with chronic kidney disease (CKD). Methods Medical records (2006–2016) were retrospectively searched for cats that had been prescribed an oral potassium supplement for management of their CKD-associated hypokalemia. For inclusion, laboratory work had to be available at the time of hypokalemia diagnosis, and at recheck within 1–6 weeks. Treatment response was defined in three ways: any increase in potassium, an increase in potassium to within the normal reference interval, and an increase to >4 mEq/l. Results Thirty-seven cats met inclusion criteria (16 PGT, 11 PGG, 10 PCG). Dosing ranged from 0.21 to 1.6 mEq/kg/day for PGT, from 0.25 to 1.48 mEq/kg/day for PGG and from 0.04 to 1.34 mEq/kg/day for PCG. After supplementation, 36/37 cats had an increase in potassium, 34/37 increased to within the reference interval and 24/37 had an increase in potassium to >4 mEq/l. There was a statistically significant difference in serum potassium post-supplementation for all three treatments: PGT ( P = 0.0001), PGG ( P = 0.001) and PCG ( P = 0.002). There was a positive correlation between PGT dose and change in potassium concentration ( P = 0.04), but there was no significant correlation for PGG or PCG. In cats that had data available, serum bicarbonate increased >2 mEq/l in 1/6 PGT, 1/6 PGG and 3/4 PCG cats. Conclusions and relevance All three potassium supplements were effective in treating hypokalemia secondary to CKD in the majority of cats despite variable dosing. Data were limited to assess the alkalinizing effect and prospective studies are needed.