Effect of long-term treatment of urinary tract infection with a single dose in the evening.

59 hospital patients with an average age of 78 years were long-term treated for urinary tract infection with either cephalexin 125 mg/day, cephalexin 250 mg/day or with nitrofurantoin 100 mg/day given as a single dose in the evening. The patients were observed for a maximum of 12 months. One single dose of cephalexin 125 mg was as effective as one single dose of 250 mg given in the evening in the long-term treatment of urinary tract infection. The urine remained free of bacteriuria in 63% of the patients treated with nitrofurantoin and in 50% of those treated with cephalexin. The duration of the bacteriuria-free interval preceding reinfection was 108 days in those patients treated with nitrofurantoin and 92 days in those treated with cephalexin.