Study Casts Doubt on Use of Common Antibiotic for UTIs in Women

Canadian researchers find other antibiotics may beat nitrofurantoin, but one expert says drug still useful

By Mary Elizabeth Dallas

Thursday, April 30, 2015

THURSDAY, April 30, 2015 (HealthDay News) -- The antibiotic most commonly prescribed for bladder and other urinary tract infections, nitrofurantoin, may not be the most effective option, new research suggests.

More than 25 percent of older adults have reduced kidney function, and bladder infections are a common complaint.

Doctors often turn to nitrofurantoin to treat these and other urinary tract infections (UTIs), but concerns have been raised about the ability of the drug to reach the urinary tract and target bacteria that causes bladder infections, especially in those with poor kidney function.

The new Canadian research was led by Dr. Amit Garg, a nephrologist at Western University in London, Ontario. His team compared the benefits of nitrofurantoin to the effectiveness of other commonly used antibiotics such as ciprofloxacin ("Cipro") and norfloxicin.

The study, published recently in the Canadian Medical Association Journal, involved 10,000 older women with low kidney function and more than 180,000 women with normal kidney function.

Researchers found that nitrofurantoin was less successful than other drugs in treating UTIs among all of the women in the study -- not just those with reduced kidney function.

What's more, the study suggests that use of nitrofurantoin for UTIs among older women may boost the odds the patient will require a second round of treatment with another antibiotic or a trip to the hospital, the researchers said.

"In our setting, nitrofurantoin was the most commonly prescribed antibiotic for a urinary tract infection in older women irrespective of their kidney function," Garg said in a journal news release.

"These patients had more treatment failures with nitrofurantoin compared with other antibiotics such as ciprofloxacin," he added. "However, this was evident regardless of a patient's level of kidney function."

One expert believes that nitrofurantoin still may have a place in the treatment of UTIs, however, especially in older patients.

"Treatment of urinary tract infections in the elderly is a balance between management of symptoms and avoidance of complications, and nitrofurantoin is one of the safer antibiotics we can offer," said Dr. Elizabeth Kavaler, a urologist at Lenox Hill Hospital in New York City.

Ciproflaxin is an alternative, but "the incidence of complications with Cipro outweighs its usefulness in many of our elderly patients with relatively benign conditions," Kavaler said. "In addition, increasing resistance to Cipro is making it less effective for the treatment of more serious conditions."

And Garg's team stressed that doctors should not avoid prescribing any antibiotic based solely on a woman's level of kidney function. They should also consider other factors, such as patterns of bacterial resistance, the researchers said.

SOURCES: Elizabeth Kavaler, M.D., urologist, Lenox Hill Hospital, New York City; Canadian Medical Association Journal, news release, April 27, 2015

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