Tolerability and Efficacy of Benazepril in Cats with Chronic Kidney Disease

The objective of the study was to test the effect of the angiotensin-converting enzyme inhibitor (ACEI) benazepril in cats with chronic kidney disease (CKD). A total of 192 cats with CKD with an initial plasma creatinine concentration ≥2 mg/dL (≥177 μmol/L) and urine specific gravity ≤ 1.025 were recruited into a double-blind, parallel-group, prospective, randomized clinical trial. Cats received daily (q24h) PO placebo (n = 96) or benazepril-HCl at a dosage of 0.5–1.0 mg/kg (n = 96) for up to 1,119 days. Most cats were fed exclusively a diet containing low amounts of phosphate, protein, and sodium. Benazepril produced a significant reduction in proteinuria, assessed by the urine protein-to-creatinine ratio (UPC, P= .005). This effect of benazepril was present in all subgroups tested, including cats with UPC <0.2, although the effect was largest in cats with higher UPCs. Plasma protein was maintained at higher concentrations with benazepril as compared with placebo during treatment in cats with initial UPC <1 (P= .038 versus P= .079 for all cats). There was no difference in renal survival time between the 2 groups when all 192 cats were compared. Mean ± SD renal survival times were 637 ± 480 days with benazepril and 520 ± 323 days with placebo (P= .47). Mean ± SD renal survival times in the 13 cats with initial UPC ≥ 1 were 402 ± 202 days with benazepril and 149 ± 90 days with placebo (P= .27). Cats with initial UPC ≥l treated with benazepril had better appetite (P= .017) as compared with those treated with placebo. Benazepril was well tolerated. In conclusion, benazepril decreased proteinuria in cats with CKD.