Bacterial prostatitis in dogs: antibiotic and castration
7-year-old intact German Shepherd with fever, lethargy, stiff gait, caudal abdominal pain and bloody urethral discharge. On rectal palpation the prostate is enlarged, symmetrical and very painful.
What is the most appropriate treatment?
chevron_right Show answer and explanation
A. Amoxicillin for 7 days
Beta-lactams penetrate the prostatic parenchyma poorly once the barrier is restored, and one week is insufficient.
B. Prostatic massage to obtain a sample and drain the exudate
In acute prostatitis massage and aspiration are painful and may spread infection (bacteraemia, sepsis). Cystocentesis urine and, later, ejaculate if possible, are enough.
C. A lipid-soluble antibiotic according to culture (fluoroquinolone or trimethoprim-sulfonamide) for about 4 weeks plus castration or antiandrogen treatment
Correct. These drugs cross the blood–prostate barrier and reach prostatic fluid. Castration (or an antiandrogen) reduces gland size and speeds resolution, reducing relapses.
D. Castration alone, without antibiotic, because prostatitis is hormonal
Castration helps, but the bacterial infection requires antimicrobial treatment.
lightbulb Key takeaway
Every intact male dog with recurrent urinary tract infection has prostatitis until proven otherwise. Repeat culture after completing treatment; prostatic abscesses will need drainage.
References: Weese JS et al. ISCAID guidelines for the diagnosis and management of bacterial urinary tract infections in dogs and cats (2019)
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.