Multiple forms of cyclooxygenase are constitutively expressed in the kidneys of many species, including dogs and cats. In some species, products of renal COX activity modulate glomerular filtration rate (GFR), thus feline GFR may be dependent on COX activity.
This study examined whether meloxicam or acetylsalicylic acid at commonly recommended dosages had any short-term effect on GFR and proteinuria in 6 euvolemic cats with renal azotemia. Renal function was assessed by serum creatinine concentration, urinary clearance of exogenously administered creatinine, and urine protein:creatinine (UP:C). Measurements from cats in a placebo group were compared with results from cats at the end of 7 days’ treatment with either meloxicam or acetylsalicylic acid. Neither drug had a measurable effect on urinary clearance of exogenously administered creatinine, serum creatinine concentration, or UP:C. No measurable effects on GFR were noted—consistent with the hypothesis that GFR of euvolemic cats with normal or reduced renal function is not dependent on cyclooxygenase function.