Urinary Tract Infection - Medications

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Continuous Preventive Antibiotics (Prophylaxis). Continuous preventive (prophylactic) antibiotics are an option for some women who do not respond to other measures. With this approach, low-dose antibiotics are taken continuously for 6 months or longer.

Typical prophylactic regimens include one dose of nitrofurantoin (50 mg), 1/2 tablet of TMP-SMX, or cephalexin (250 mg) daily. Taking the antibiotic at bedtime may be most effective. Studies suggest that continuous prophylactic antibiotics reduces recurrences by up to 95% and may prevent kidney infection.

Adverse effects mostly include gastrointestinal problems and yeast infections. (Taking probiotic supplements or eating yogurt may help prevent yeast infections.) Although there is concern that continuous risk increases the risk for bacteria that are resistant to the antibiotics, studies to date have not reported any significant risk even up to 5 years of use.

Antibiotics for Kidney Infections (Pyelonephritis)

Treating Uncomplicated Kidney Infections. Patients with uncomplicated kidney infections (pyelonephritis) may be treated at home with oral antibiotics. Such patients are healthy and nonpregnant. They typically are experiencing fever, chills, and flank pain. However, they are not nauseous or vomiting and show no symptoms or signs of kidney involvement or complicated infection.

The standard treatment for uncomplicated pyelonephritis is a 14-day course of oral antibiotics, usually trimethoprim-sulfamethoxazole (TMP-SMX) or a fluoroquinolone. Sometimes patients with uncomplicated pyelonephritis are first given an antibiotic injection, if indicated.

Oral amoxicillin or amoxicillin-clavulanate (Augmentin) may be prescribed for women with bacteria (gram-positive organisms, including Enterococcus species and S. saprophyticus) that do not respond to standard regimens.

A urine culture is may be obtained within 1 week of completion of therapy and again 4 weeks later.

Treating Moderate to Severe Kidney Infections. Patients with moderate to severe acute kidney infection and those with severe symptoms or other complications may need to be hospitalized. In such cases, antibiotics (ceftriaxone and gentamicin) are usually given intravenously for 3 to 5 days or until symptoms are relieved and patients have not shown any signs of fever for 24 to 48 hours.