For an uncomplicated urinary tract infection, the usual duration of norfloxacin therapy is

• A. 3 to 5 days
• B. 5 to 7 days
• C. 7 to 10 days
• D. 10 to 14 days

Answer: (C)

Durations of antibiotics for an uncomplicated urinary tract infection are chosen to ensure the bacteria are exposed to the drug long enough to be completely eradicated and to minimize relapse. Norfloxacin is a fluoroquinolone that achieves active concentrations in the urine, but to reliably clear the infection and prevent recurrence, a course long enough to maintain effective exposure is used. Seven to ten days provides that sustained level to adequately eradicate common pathogens such as E. coli and to promote symptom resolution. Shorter courses may be insufficient for complete clearance with this antibiotic. As always, finish the entire course even if symptoms improve, and seek care if symptoms persist, worsen, or fever develops.