Urinary Biomarker Profile for Early Detection of Nephrotoxicity in Dogs Treated with Aminoglycoside Antibiotics at a Referral Hospital in Lagos State

Aminoglycoside antibiotics are commonly used in small animal practice in Nigeria for management of resistant bacterial infections, and nephrotoxicity is a known dose-limiting adverse effect requiring early biochemical detection. This study characterised urinary biomarker profiles for early nephrotoxicity detection in dogs receiving aminoglycoside therapy at a referral veterinary hospital in Lagos State, South West Nigeria. Forty dogs receiving gentamicin at standard therapeutic doses were enrolled alongside twenty healthy controls. Urine samples collected at baseline, day three, day seven, and day fourteen were assayed for gamma-glutamyl transferase, N-acetyl-beta-D-glucosaminidase, albumin-to-creatinine ratio, and cystatin C. Serum creatinine and blood urea nitrogen were measured concurrently. Urinary gamma-glutamyl transferase and N-acetyl-beta-D-glucosaminidase showed significant elevation as early as day three in fourteen of forty treated dogs, preceding any changes in serum creatinine or blood urea nitrogen. The albumin-to-creatinine ratio became significantly elevated by day seven in the same subset. Serum creatinine remained within the reference range in all animals at day seven, confirming the superior early sensitivity of urinary enzyme markers. Dogs with urinary biomarker elevations at day three were more likely to develop clinically significant nephrotoxicity by day fourteen. These findings establish an early urinary biomarker detection algorithm for aminoglycoside nephrotoxicity in Nigerian companion animal practice and support protocol modification for at-risk patients. Keywords: aminoglycoside nephrotoxicity, urinary biomarkers, gamma-glutamyl transferase, dogs, Lagos.