Table 2: Antimicrobial treatment options for urinary tract infections in the dog and cat.

DrugDoseComments

Amoxicillin11–15 mg/kg PO q8hGood first-line option for UTIs. Excreted in urine predominantly in active form if normal renal function is present. Ineffective against beta-lactamase-producing bacteria.

AmikacinDogs: 15–30 mg/kg IV/IM/SC q24h Cats: 10–14 mg/kg IV/IM/SC q24hNot recommended for routine use but may be useful for treatment of multidrug resistant organisms. Potentially nephrotoxic. Avoid in animals with renal insufficiency.

Amoxicillin/clavulanate12.5–25 mg/kg PO q8h (dose based on combination of amoxicillin + clavulanate)Not established whether there is any advantage over amoxicillin alone.

AmpicillinNot recommended because of poor oral bioavailability. Amoxicillin is preferred.

Cephalexin, Cefadroxil12–25 mg/kg PO q12hEnterococci are resistant. Resistance may be common in Enterobacteriaceae in some regions.

Cefovecin8 mg/kg single SC injection. Can be repeated once after 7–14 days.Should only be used in situations where oral treatment is problematic. Enterococci are resistant. Pharmacokinetic data are available to support the use in dogs and cats, with a duration of 14 days (dogs) and 21 days (cats). The long duration of excretion in the urine makes it difficult to interpret posttreatment culture results.

Cefpodoxime proxetil5 to 10 mg/kg q24h POEnterococci are resistant.

Ceftiofur2 mg/kg q12-24h SCApproved for treatment of UTIs in dogs in some regions. Enterococci are resistant.

ChloramphenicolDogs: 40–50 mg/kg PO q8hCats: 12.5–20 mg/kg PO q12hReserved for multidrug resistant infections with few other options. Myelosuppression can occur, particularly with long-term therapy. Avoid contact by humans because of rare idiosyncratic aplastic anemia.

Ciprofloxacin30 mg/kg PO q24hSometimes used because of lower cost than enrofloxacin. Lower and more variable oral bioavailability than enrofloxacin, marbofloxacin, and orbifloxacin. Difficult to justify over approved fluoroquinolones. Dosing recommendations are empirical.

Doxycycline3–5 mg/kg PO q12hHighly metabolized and excreted through intestinal tract, so urine levels may be low. Not recommended for routine uses.

Enrofloxacin5 mg/kg PO q24h (cats)10–20 mg/kg q24h (dogs)Excreted in urine predominantly in active form. Reserve for documented resistant UTIs but good First-line choice for pyelonephritis (20 mg/kg PO q24h). Limited efficacy against enterococci. Associated with risk of retinopathy in cats. Do not exceed 5 mg/kg/d of enrofloxacin in cats.

Imipenem-cilastatin5 mg/kg IV/IM q6-8hReserve for treatment of multidrug-resistant infections, particularly those caused by Enterobacteriaceae or Pseudomonas aeruginosa. Recommend consultation with a urinary or infectious disease veterinary specialist or veterinary pharmacologist prior to use.

Marbofloxacin2.7–5.5 mg/kg PO q24hExcreted in urine predominantly in active form. Reserve for documented resistant UTIs but good First-line choice for pyelonephritis. Limited efficacy against enterococci.

Meropenem8.5 mg/kg SC/IV q 12 (SC) or 8 (IV)hReserve for treatment of multidrug-resistant infections, particularly those caused by Enterobacteriaceae or Pseudomonas aeruginosa. Recommend consultation with a urinary or infectious disease veterinary specialist or veterinary pharmacologist prior to use.

Nitrofurantoin4.4–5 mg/kg PO q8hGood second-line option for simple uncomplicated UTI, particularly when multidrug-resistant pathogens are involved.

OrbifloxacinTablets: 2.5–7.5 mg/kg PO q24h; oral suspension: 7.5 mg/kg PO q24h (cats) or 2.5-7.5 mg/kg PO q24h (dogs)Excreted in urine predominantly in active form.

Trimethoprim-sulfadiazine15 mg/kg PO q12hNote: dosing is based on total trimethoprim + sulfadiazine concentrationGood first-line option. Concerns regarding idiosyncratic and immune-mediated adverse effects in some patients, especially with prolonged therapy. If prolonged (>7d) therapy is anticipated, baseline Schirmer’s tear testing is recommended, with periodic re-evaluation and owner monitoring for ocular discharge. Avoid in dogs that may be sensitive to potential adverse effects such as KCS, hepatopathy, hypersensitivity, and skin eruptions.