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Does Flagyl treat UTI infections?

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on Dec 1, 2023.

Official answer


Flagyl is not typically used to treat a urinary tract infection (UTI). The preferred oral treatments for uncomplicated UTI infections (acute cystitis) are:

  • nitrofurantoin (Furadantin, Macrobid, Macrodantin)
  • fosfomycin (Monurol)
  • sulfamethoxazole-trimethoprim (Bactrim DS, Septra DS, others)

If you are diagnosed with a UTI, your doctor will choose your antibiotic based on your history, allergies, type of UTI, local resistance patterns, and price and insurance considerations. Do not use or share “left-over” antibiotics you have because it may not kill the bacteria in the UTI.

First-line options for uncomplicated UTI are usually selected from nitrofurantoin, fosfomycin and sulfamethoxazole-trimethoprim. Amoxicillin / clavulanate (Augmentin) and certain cephalosporins may be appropriate options when first-line options cannot be used.

With the correct antibiotic, your symptoms should begin to clear up about 1 to 2 days after starting treatment. Your doctor may order a urine culture to more precisely identify the bacteria and tailor your therapy.

Length of treatment for a UTI can range from a single, one-time dose, to a course of medication over 5 to 7 days. Kidney infections may require hospitalization, a longer course of antibiotic, and antibiotic injections depending upon the severity of your UTI.

The good news is that sometimes a UTI can clear up on its own in women without antibiotic use (meaning it’s self-limiting). If needed, most uncomplicated UTI cases can be treated quickly with a short course of oral antibiotics.

Treatment for men is similar to women for uncomplicated cases. Different treatments, such as fluoroquinolone antibiotics (ciprofloxacin, levofloxacin) may be needed for men with more complicated UTIs and prostate involvement.

What is Flagyl used to treat?

The FDA first approved Flagyl (generic name: metronidazole) way back in the 1960's, so it's an older antibiotic used for decades.

Metronidazole (Flagyl) is bactericidal (kills bacteria) and is also used to treat protozoal infections. It is a potent drug in the nitroimidazole class used to treat bacterial infections of the:

  • bloodstream
  • brain and spinal cord
  • heart
  • liver
  • lungs
  • joints
  • skin
  • stomach
  • vagina

Flagyl is also used to treat trichomoniasis, a sexually transmitted disease (STD) caused by a parasite, even if there are no symptoms. Usually both sexual partners are treated at the same time.

Metronidazole is used to treat many common infections, some of which include:

  • bacterial vaginosis
  • bacterial stomach or intestinal infections (severe infectious diarrhea)
  • pelvic inflammatory diseases
  • bone infection or swelling
  • peritonitis
  • pseudomembranous colitis
  • liver abscess
  • skin infection
  • soft tissue infection
  • skin and structure Infection
  • trichomoniasis
  • wound infections

The usual duration of therapy is 7 to 10 days, but you may need to take it longer. Always follow your doctor’s direction for dosing and duration of treatment.

Don't share antibiotics with anyone - they are specific for the type of infection they treat and may be harmful if taken by someone else without a healthcare provider’s approval. Antibiotics have no action on viral infections like a cough, cold, the flu, or COVID-19.

Learn more: Flagyl Uses, Warnings and Side Effects (in more detail)

This is not all the information you need to know about Flagyl (metronidazole) for safe and effective use and does not take the place of your doctor’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.

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