Results of a surveillance system for adverse effects in leprosy's WHO/MDT

The implementation of the World Health Organization's multidrug therapy (WHO/MDT) in Brazil began slowly and gradually in 1986, and in 1991 it was adopted officially by the Brazilian Ministry for Health. After 1991, during the intensive phase of WHO/MDT implementation, there was some concern about the number of cases of renal failure observed in several Brazilian states, including some fatalities. This was the motive behind the state of São Paulo's Health Department's decision to carry out a study that would evaluate not only the incidence rate of adverse effects of rifampin in relation to kidney function but also in relation to the use of WHO/MDT in general. Due to the existence in the state of São Paulo of health services with a program for the control of Hansen's disease and an organized and stratified system of epidemiological surveillance, it was possible to elaborate a subsystem for data collecting. During the period from July 1991 to December 1993, 20,667 patients were treated with WHO/MDT. Among this group there were 127 notifications considered as adverse effects, mainly: "flu"-like syndrome (54), acute renal failure (20), cutaneous reactions (15), toxic hepatitis (15), gastrointestinal complaints (8), hemolytic anemia (6), methemoglobinemia (4), thrombocytopenic purpura (2), hypotension (2) and disseminated intravascular coagulation (1). There was a predominance of adverse effects among multibacillary (MB) patients and the majority of the reactions occurred before the 6th dose; 82.7% of MB patients had had previous treatment with dapsone and rifampin and, due the fact that most severe reactions were related to rifampin, a booster mechanism could be an explanation for this occurrence. So far, there are seven published reports on renal failure in the world, and in Brazil only in the state of Søao Paulo there were 20 cases reported among 20,667 patients under WHO/MDT treatment, This striking difference deserves a better explanation, but in no way do these reports undermine the positive aspects of WHO/MDT. However, the authors believe that a world alert about its possible serious side effects is not only necessary but ethically required.