Ciprofloxacin dosing adjustments are typically required when the patient’s creatinine clearance falls below which value?

• A. Less than 30 mL/min
• B. Less than 60 mL/min
• C. Less than 15 mL/min
• D. Less than 10 mL/min

Answer: (A)

Ciprofloxacin is cleared largely by the kidneys, so reduced kidney function directly lowers its clearance. When creatinine clearance falls below 30 mL/min, the drug can accumulate if you keep giving the standard dose, raising the risk of toxicity. Therefore dosing must be adjusted (lowering the dose or extending the interval) once CrCl is under 30 mL/min. This threshold is the one used in Beers criteria guidance for ciprofloxacin. If CrCl is above 30 mL/min, standard dosing is generally acceptable, while far milder or far more severe impairment would require different considerations rather than the 30 mL/min cutoff.