ABSTRACT
Efficient drugs against Chagas' disease must have an effect on the amastigote forms or intracellular reproduction elements of Trypanosoma cruzi (T. cruzi). Trypomastigote and epimastigote forms derive from the former and their response to medications is less marked. The only drugs used in humans are nifurtimox (NF) and benznidazole (BNZ). Other useful medications are allopurinol and itraconazole. NF acts producing free radicals and BNZ inhibits the synthesis of macromolecules. There is consensus that Chagas' disease must be treated in all its periods, since T.cruzi DNA is detected by polymerase chain reaction in chronic cases, even when microscopy is negative. The pharmacological treatment modifies the natural evolution of the disease. It also helps to solve a public health problem, considering that there is a high number of subjects with Chagas' disease. Subjects with chronic chagasic cardiomyopathy with terminal heart failure are the only cases without indication for treatment. Due to the digestive and skin secondary effects of the drugs, treated patients must be controlled clinically and with complete blood counts and hepatic proiles before, during and after the therapy. Approximately 30 percent of patients will experience secondary effects. Children have a better tolerance to the drugs. Congenital or acquired acute, intermediate and chronic cases should be treated.