Administration of nitrofurantoin in dogs with lower urinary tract infections: 14 cases (2013-2019)

Abstract

Objectives: The purpose of this study was to describe the clinical use of nitrofurantoin in client-owned dogs with lower urinary tract infections. The primary aim was to describe the patient population, dosage, treatment duration, outcome and side effects.

Materials and methods: Medical records in an institution were retrospectively reviewed from July 2013 to January 2019.

Results: Nitrofurantoin was prescribed in this clinical population of 14 client-owned dogs for lower urinary tract infections. Recurrent urinary tract infection was the clinical diagnosis in all dogs. Each dog's urinary tract infection was associated with a nitrofurantoin-susceptible, multidrug-resistant uropathogen. The median dosage and duration of nitrofurantoin treatment was 4.3 mg/kg by mouth every 8 hours for 14 days. Twelve of the 14 dogs had successful outcomes including bacteriologic cure (n = 9), clinical cure (2) and resolution of target bacteria (1). Treatment failures (n = 2) were associated with uropathogens developing progressive nitrofurantoin resistance.

Clinical significance: In some dogs with recurrent lower urinary tract infections, nitrofurantoin may be an effective antibiotic for treatment of nitrofurantoin-susceptible uropathogens. Treatment failures were associated with progressive uropathogen resistance. Urine bacterial culture and quantitative susceptibility testing are essential to initiating and monitoring treatment due to the multidrug-resistant isolates and, in some cases, persistent bacteriuria in the face of treatment.