Bag and colleagues prospectively randomized 101 patients with greater than 2.5-cm kidney stones and/or hydronephrosis with sterile preoperative urine cultures to a 7-day course of nitrofurantoin versus no antibiotics before PCNL and found a statistically significant lower rate of postoperative SIRS (19% vs 49%), endotoxemia (18% vs 42%), positive result on kidney urine culture (0% vs 10%), and positive result on stone culture (8% vs 30%) in the arm receiving nitrofurantoin.