Concentrations of isometamidium chloride (Samorin®) in sera of Zebu cattle which showed evidence of hepatotoxicity following frequent trypanocidal treatments

Abstract

The concentrations of isometamidium circulating in poorly nourished Zebu cattle which showed morbidity, mortality, and biochemical and histopathological evidence of hepatotoxicity, following frequent treatments with isometamidium chloride and diminazene aceturate were investigated using the isometamidium-ELISA. As few as two isometamidium treatments one month apart were associated with significant weight loss, and cattle treated with diminazene aceturate after three or four isometamidium treatments suffered a 50% mortality. Although there were no obvious, marked elevations in isometamidium concentration which might have allowed the use of the ELISA as a predictor of a potential toxicity problem, concentrations did increase significantly with the number of monthly treatments administered, suggesting drug accumulation, and the increases were significantly higher in cattle to which diminazene had also been administered. In cattle treated with both trypanocides, weight loss and serum glutamate dehydrogenase levels were correlated with isometamidium concentrations. These observations, together with the histopathological findings, support the hypothesis that the morbidity and mortality observed were related to the repeated treatment with isometamidium in conjunction with diminazene aceturate, and that the pathogenesis involved a component of hepatic damage. It is therefore recommended that cattle, particularly those under nutritional stress, are not subjected to repeated treatments with isometamidium at intervals as short as one month, and particularly not with concurrent administration of diminazene.

Metabolism of isometamidium in hepatocytes isolated from control and inducer‐treated rats

“…Isometamidium was not toxic to isolated suspensions of hepatocytes within the 4 h incubation period used for metabolic studies. Toxicity has, however, been detected after longer exposure of cultured hepatocytes to ISM for 24 h (unpublished observations) and this correlates with in vivo observations of hepatotoxicity in Zebu cattle (Eisler et al, 1997).…”

Current Treatments to Control African Trypanosomiasis and One Health Perspective

“…In these conditions, the results obtained in mice experiments are not always applicable in ruminants. Serum trypanocide drug concentrations can be determined by ELISA [ 52 ]. If the drug concentration in samples obtained from infected and treated animals is above a pre-defined cut-off (ex.…”