A prospective, randomized, double-blinded study comparing the efficacy and side effects of alfuzosin and terazosin for treatment of vesico-urethral reflex dyssynergia in dogs

Abstract

Twenty-six male dogs with vesico-urethral reflex dyssynergia (VURD) were treated randomly with alfuzosin or terazosin 0.25 mg/kg twice daily for six weeks to compare efficacy, side effects and long term effects. Dogs were referred to the Clinic for Companion Animals of Utrecht University with signs of (partial) urethral obstruction. Physical examination, abdominal ultrasonography, urinalysis and a radiographic contrast study (urethrocystography) were routinely performed. If no mechanical causes of obstruction or disease of the distal urinary tract were observed, the diagnosis VURD was presumed and the dogs were included in the study. Data were obtained weekly during contact with the owners during the treatment period. Later follow-up information was obtained from owners or referring veterinarians. The dogs had a mean age of 7.2 years, and a mean weight of 43 kg. Labrador Retrievers made out 54% of the study group. The amount of dogs that had a good response to treatment in the alfuzosin group (n=7) was not significantly higher compared to the terazosin group (n=2; P=0.089). The amount of dogs with mild dysuria that had a good response to treatment in the alfuzosin group (n=6) was on the edge of being significantly more compared to the terazosin group (n=1; P=0.05).The response to treatment was not significantly different between castrated dogs and non-castrated dogs (P=1.000) and between surgically and chemically castrated dogs (P=0.580). The response to treatment between Labrador Retrievers and other breeds was without difference (P=1.000). There was no significant difference in the amount of dogs in which side effects were reported between the treatment groups (P=0.401), castrated and non-castrated dogs (P=1.000), surgically and chemically castrated dogs (P=1.000) and between Labrador Retrievers and other breeds (P=0.683). Significantly more dogs treated with terazosin (n=5) had severe side effects in which treatment was either ceased or tapered (n=0; P=0.042). No significant difference in survival time was found between treatment groups (P=0.604) and between Labrador Retrievers and other breeds (P=0.515). Dogs that were surgically castrated prior to or during treatment had a significant better survival time (P=0.044). The survival time of a dog was significantly less when dogs had severe dysuria (P=0.029). The duration of dysuria prior to treatment made no significant difference in the survival time (P=0.705).