Skip to main content

Does Flagyl treat UTI infections?

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

Official answer

by drugclasses.com

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.

Related questions

References

Read next

Does Flagyl cause diarrhea?

Flagyl is well-known for causing diarrhea, as well as other stomach side effects like nausea, heartburn and stomach pain. Diarrhea is common and occurs in about 1% to 10% of patients. Flagyl may also cause an unpleasant metallic taste during therapy which can lead to nausea and a decreased appetite. Continue reading

What happens if you drink alcohol with metronidazole?

Drinking alcohol while taking metronidazole is not recommended because the combination of metronidazole and alcohol can cause a reaction (often referred to as a disulfiram-like reaction) in some people. Symptoms may include flushing, headaches, nausea, vomiting, and stomach cramps. There has been one reported death associated with this reaction. The product information and health professionals recommend not to drink alcohol during metronidazole treatment and for 3 days after finishing the course. Continue reading

How long does it take for metronidazole to work?

Metronidazole starts to work 1 to 2 hours after you take it, because it is quickly absorbed, and it reaches its maximum concentration after 20 minutes to 3 hours. But it may take a couple of days before you start to feel better or notice an improvement in your symptoms. It is important that you still finish the course of metronidazole that your doctor has prescribed, even if you feel better, because the infection may still be present, and it could flare up or recur if you haven’t finished the course. Continue reading

Related medical questions

Drug information

Related support groups