Cystitis/Asymptomatic Bacteriuria

Nitrofurantoin is likely to be ineffective for those with creatinine clearance less than 30 mL/min – this may apply to elderly patients (greater than 75 years old) with otherwise normal creatinine.

Inadequate tissue/blood levels are achieved for treating upper urinary tract infections or bacteremia.

Use nitrofurantoin macrocrystals if less than 36 weeks gestation.

Do not use nitrofurantoin to treat pyelonephritis because of negligible drug levels in serum and renal parenchyma.