Intramuscular administration of sodium antimony dimercapto succinate (TWSb) given in five doses was found to have a strong prophylactic and therapeutic activity in experimental infections with Schistosoma mansoni (Puerto Rican strain) in monkeys. The dosage level necessary to bring about satisfactory results in these animals was well below toxic levels.
Conversely, TWSb was relatively ineffective in mice although the drug was given in comparatively higher doses, some at the toxic level, over a much longer period of time. A significant reduction in worm burdens was observed only in those mice which were given prolonged treatment at high doses begining seven days before exposure to infection. In other groups, a shift of worms to the liver was the only evidence of anthelminthic activity of TWSb.