Which regimen is an appropriate first-line empiric therapy for uncomplicated urinary tract infection in nonpregnant women when local resistance allows?

• A. Nitrofurantoin for 5 days
• B. Ciprofloxacin for 7 days
• C. Amoxicillin for 10 days
• D. Doxycycline for 7 days

Answer: (D)

Choosing empiric therapy for uncomplicated cystitis in a nonpregnant woman means using an antibiotic that reaches high concentrations in the urine and effectively covers the common pathogens, mainly E. coli, while taking local resistance patterns into account. Nitrofurantoin given for five days fits this goal well: it concentrates in the urine, is active against typical urinary pathogens, and has a favorable resistance profile when used for lower urinary tract infections. If local data show sufficient susceptibility of E. coli to trimethoprim-sulfamethoxazole, that agent for about three days is another reasonable first-line option. Doxycycline, amoxicillin, and fluoroquinolones like ciprofloxacin are not preferred first-line choices here: doxycycline and amoxicillin often have unreliable activity against the usual pathogens, and ciprofloxacin is avoided as a routine first-line due to higher resistance and broader adverse effect considerations.