Updated September 25, 2026. Fact-checked against veterinary sources; review by a licensed veterinarian is in progress. See our editorial policy.
Quick answer: Bacterial urinary tract infections (UTIs) in dogs are treated with prescription antibiotics. For a simple bladder infection in an otherwise healthy dog, international guidelines recommend a common antibiotic such as amoxicillin or trimethoprim-sulfonamide for a short course of about 3–5 days, ideally guided by a urine culture. Kidney infections, prostate infections, and repeat infections need longer treatment and further testing. The right drug and dose depend on your dog, so never use leftover or human antibiotics.
This guide explains treatment in general and doesn’t give doses. Your dog’s dose must come from your vet.
Signs of a UTI
- Peeing small amounts often, or urgently
- Straining or discomfort when urinating
- Blood in the urine, or cloudy or strong-smelling urine
- Accidents in the house
- Licking the genital area
Fever, vomiting, back pain, or lethargy can mean a kidney infection. Straining with little or no urine is an emergency.
Why testing matters
- Urinalysis shows signs of infection, crystals, and blood.
- Urine culture confirms bacteria and shows which antibiotics will work, ideally from a sample collected directly from the bladder with a fine needle.
- Stones, tumors, and other conditions can look like a UTI and won’t respond to antibiotics.
How vets treat different types of UTI
- Simple (sporadic) bladder infection: a first-line antibiotic like amoxicillin or trimethoprim-sulfonamide for about 3–5 days, per the International Society for Companion Animal Infectious Diseases (ISCAID).
- Recurrent infections (3 or more in a year, or returning soon after treatment): a culture every time, and a search for the underlying cause, such as stones, diabetes, Cushing’s disease, or anatomy.
- Kidney infection (pyelonephritis): longer treatment, usually 10–14 days, with follow-up testing.
- Prostate infection in male dogs: antibiotics that penetrate the prostate, for several weeks, and often neutering.
- Bacteria without symptoms: often don’t need antibiotics.
- Pain relief may be added for comfort.
Some antibiotics, such as fluoroquinolones, are reserved for infections where culture shows they’re needed, to limit resistance.
Side effects to watch for
- Vomiting, diarrhea, or poor appetite. Giving the drug with food may help, if your vet agrees.
- With trimethoprim-sulfonamide, especially with longer use: dry eye, skin reactions, liver problems, joint pain, or low thyroid levels. Doberman Pinschers are more sensitive.
- Allergic reactions, such as hives or facial swelling.
Call your vet if side effects appear, or if signs don’t improve within a couple of days.
Giving antibiotics correctly
- Give every dose at the right time, for the full course prescribed.
- Don’t save leftover pills for next time.
- Use the measuring syringe for liquids.
- Tell your vet about all other medications and supplements.
What to avoid
- Human antibiotics or leftover prescriptions: they may be the wrong drug or dose and encourage resistant bacteria.
- Human urinary pain relievers (AZO/phenazopyridine).
- Relying on cranberry or supplements to treat an active infection.
Frequently asked questions
How fast do antibiotics work for a dog UTI?
Most dogs feel better within 1–3 days. If not, call your vet.
Can a dog UTI go away without antibiotics?
Some mild infections may clear, but untreated infections can spread to the kidneys. Get a urine test to know what you’re treating.
Can I give my dog amoxicillin from my own prescription?
No. The dose, formulation, and whether it’s the right drug all need to come from your vet.
See also: urinary health supplements for dogs.
Sources
- Weese JS, et al. ISCAID guidelines for the diagnosis and management of bacterial urinary tract infections in dogs and cats. Vet J. 2019
- Merck Veterinary Manual: Bacterial cystitis in small animals
- Merck Veterinary Manual: Sulfonamides and sulfonamide combinations
- Trepanier LA. Idiosyncratic toxicity associated with potentiated sulfonamides in the dog. J Vet Pharmacol Ther. 2004
This article is for general education and is not a substitute for care from your own veterinarian. Learn about The Pet Vet and our editorial policy.