Abstract

Until five years ago when preparations of trimethoprim alone began to be marketed,^1,2 the drug was available only in combination with a sulphonamide. The only combination still marketed now is co-trimoxazole (trimethoprim + sulphamethoxazole; Septrin and other brands). The inclusion of a sulphonamide entails greater toxicity, but is also claimed to increase efficacy and prevent acquired resistance. This article reassesses the arguments.