Effect of niridazole on Schistosoma mansoni. Clinical and experimental results
Tribouley, J.; Tribouley-Duret, J.; Pautrizel, A.N.; Pautrizel, R.
Bulletin de la Societe de Pathologie Exotique et de Ses Filiales 65(4): 550-563
1972
ISSN/ISBN: 0037-9085 PMID: 4679130 Document Number: 48651
Niridazole was given orally at 25mg/kg body-weight each day for 7 days to 121 patients, in hospital for other ailments, who had Schistosoma mansoni infections. 4 weeks after treatment, the number of patients passing eggs in the faeces had decreased considerably although some were still passing eggs after 6 months. None of the 39 examined 30 months after treatment had eggs in the faeces. Serological examinations on 88 patients showed a temporary drop in antibody titre towards the 7th day after treatment followed by a rapid rise to a peak about 4 weeks after treatment. The titre then fell fairly rapidly for a short time and then more gradually. Antibodies had disappeared from 10 of 43 patients examined at the end of the 2nd year. Information on observed side effects is given. In 14 cases, of which 7 were chronic alcoholics, serious neuropsychic manifestations occurred, treatment had to be terminated and Valium or Largactil given to ameliorate the condition. In contrast to these patients, who had serious liver damage it is noted that 21 neuropsychiatric patients, free of any liver disease, suffered no aggravation of their condition as a result of niridazole treatment. in the experimental part of this work, the action of niridazole was studied in mice and rabbits infected with S. mansoni. It was given to both by gastric sound at a dose rate of 100mg/kg/day for 10 days, to rabbits as an emulsion in 0.1% Tween 80 in saline (9g% NaCl) and to mice as a finely pulverized suspension in gum arabic and syrup. These experiments confirmed the indication that in the human cases not all the adult schistosomes had been killed by niridazole and demonstrated that treatment destroyed a higher percentage of schistosomes in heavy infections than in light. This is explained by the fact that as niridazole is broken down in the liver and its metabolites are inactive against schistosomes, the greater the liver deficiency the longer is its therapeutic activity. But, under these conditions, the toxicity of niridazole is also augmented.