Which antibiotic option is appropriate for outpatient treatment of acute pyelonephritis in a nonpregnant woman?

• A. Ciprofloxacin
• B. Amoxicillin
• C. Nitrofurantoin
• D. Doxycycline

Answer: (A)

Outpatient management of acute pyelonephritis in a nonpregnant woman requires an antibiotic that can reach the kidney in effective amounts and cover the common gram-negative pathogens, especially E. coli. Ciprofloxacin does this well because it has high oral bioavailability and penetrates renal parenchyma and urine adequately, making it suitable for a mild-to-moderate kidney infection treated outside the hospital. Nitrofurantoin concentrates in the urine but does not achieve sufficient systemic or renal tissue levels, so it isn’t reliable for pyelonephritis. Amoxicillin often fails due to resistance among community uropathogens, limiting its usefulness for this condition. Doxycycline has less consistent activity against the typical organisms causing pyelonephritis and isn’t a preferred first-line option. Thus, the most appropriate outpatient choice is ciprofloxacin, with a typical course of several days depending on guidelines and response.