Urinary tract infection and oral penicillin G

The urinary excretion of three oral preparations of penicillin G was measured in six subjects. After a dose of 500 mg of potassium penicillin G the mean urine level was 597 mug/ml in the first of three two-hour periods, 324 mug/ml in the second, and 40 mug/ml between the fourth and sixth hours. Of the dose, 13.4% was excreted in the urine in 24 hours. Differences among the three preparations were not significant therapeutically. Most Gram-negative urinary pathogens are sensitive to 5-50 mug of penicillin G per ml. There is a rational basis for the use of oral penicillini G to treat urinary infection due to Gram-negative bacilli.