Does Metronidazole Treat UTI? & Best Alternatives.

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The Short Answer:

No, Metronidazole is not recommended for UTI treatment, Unless your doctor recommends it based on a urine culture and sensitivity testing.

Quick Insights:

Metronidazole (Flagyl®) is an antibiotic used to treat certain bacterial species but is ineffective for UTIs.
Metronidazole is used for the treatment of bacterial vaginosis.

Metronidazole is not recommended for recurrent UTIs, as it may increase the risk of recurrent UTIs.
Topical metronidazole is not recommended for treating UTI, as it does not reach the urinary system.
Alternatives to metronidazole for UTI include Nitrofurantoin, Trimethoprim/sulfamethoxazole, Fosphomycin, Cephalosporins and Fluoroquinolones.

[1] Metronidazole doesn’t treat a UTI.

Metronidazole (Flagyl®) is a famous antibiotic active against a group of bacterial species called (anaerobic bacteria).

It is commonly used in conditions such as:

Giardiasis.

Amoebiasis.
Intraabdominal Infections.
Bacterial gastroenteritis.

H. pylori infections.
Bacterial Vaginosis.

Metronidazole is not effective and is not recommended as a treatment for UTI. Most cases of UTI are caused by E. Coli (up to 90% of the cases), which is resistant to metronidazole.

Metronidazole (both oral and topical) is used for the treatment of a closely related condition called bacterial vaginosis (BV) (reference).

Bacterial vaginosis is when vaginal flora (beneficial bacteria inside the vagina) becomes imbalanced and causes pH changes leading to multiple problems such as infections, discharge, bad odor, etc.

[2] Metronidazole is not suitable for recurrent UTIs.

According to the guidelines for simple recurrent UTIs in women (a common problem), some antibiotics can be taken to prevent such a condition.

However, Metronidazole wasn’t listed among the recommended antibiotics for recurrent UTIs.

Moreover, Studies show that the unnecessary use of metronidazole is a risk factor for recurrent UTIs (reference).

So, don’t use metronidazole for recurrent UTIs unless prescribed by your doctor.

[3] Can metronidazole Cause UTI?

Metronidazole is an antiotics that fights bacteria. However, it may lead to either:

Changes in the normal bladder microbiota (destroying the beneficial bacteria in your urinary tract).
Increase the chances of bacterial resistance (taking a weak antibiotic such as metronidazole may make the bacteria stronger and difficult to treat).

Because of the above effects, Metronidazole may increase the risk of getting UTIs. According to Lexicomp® online drug database, 2% of people taking metronidazole may get UTI.

[4] Topical metronidazole and UTI.

Metronidazole is available in a topical form (a cream or a gel). However, topical metronidazole is not recommended for treating UTI.

Like oral metronidazole, topical forms of metronidazole (such as vaginal gel or suppositories) are not recommended for UTI treatment as it is generally ineffective for this type of infection.

Moreover, topical metronidazole is applied in the vaginal cavity and doesn’t reach the urinary system.

[5] Alternatives to metronidazole for UTI.

The most common antibiotics prescribed for UTIs are:

Nitrofurantoin (Macrodantin®, Furadantin®).
Trimethoprim/sulfamethoxazole (Bactrim®, Septra®).
Fosphomycin (Monurol®).

Cephalosporins (Keflex®, Ceftin®, Suprax®).
Fluoroquinolones (Cipro®, Levaquin®).

The table below illustrates the doses of the commonly used antibiotics for UTI (reference):

ANTIBIOTIC	DOSE	DURATION
Nitrofurantoin (Macrobid®)	100 mg Tablets twice daily	5 days.
Trimethoprim-Sulfamethaxal (Septra®).	160/800 mg Twice daily	3 days
Fosfomycin (Monurol®)	3 g oral tablets.	Single dose
Trimethoprim (for patients with Sulfa allergy)	100 mg oral tablets twice daily	3 days.

Evidence-based
Written by a doctor.

MD, Internal Medicine and Nephrology specialist.

Dr. Esraa A. MagidAuthor

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