Co-trimoxazole in the long-term treatment of pyelonephritis with normal and impaired renal function.

: The effect of co-trimoxazole was studied in 29 cases of acute or chronic pyelonephritis. The therapy produced the desired effect in 22 out of 23 cases and in the 6 cases treated prophylactically. We used a special dosage schedule for the combination of sulphamethoxazole and trimethoprim in the treatment of patients with normal renal function and with varying degrees of renal impairment. The results show that the plasma concentrations were at satisfactory therapeutic levels, with no accumulation of the three substances and without causing any toxic side effects, even in patients with severe impairment of the renal function. The mean duration of the treatment was 12.3 months. The material is, however, not largelu enough to warrant the recommendation of standardized treatment according to the schedule described, in spite of the favourable experience gained. It does, however, permit us to recommend that the plasma concentrations should be determined, particularly of the total sulphamethoxazole in patients with severely impaired renal function.