Table 1: Summary of first-line antimicrobial options for UTIs in the dog and cat.

Infection TypeFirst-line drug options

Uncomplicated UTIAmoxicillin, trimethoprim-sulfonamide
ComplicatedGuided by culture and susceptibility testing, but consider amoxicillin or trimethoprim-sulfonamide initially
Subclinical bacteriuriaAntimicrobial therapy not recommended unless high risk for ascending infection. If so, treat as per complicated UTI
PyelonephritisStart with a fluoroquinolone, with re-assessment based on culture and susceptibility testing