Carbarsone: Its Action on the Intestinal Trichomonads of Rats In Vivo

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  • Department of Protozoology, The Johns Hopkins University School of Hygiene and Public Health, Baltimore, Maryland


The studies and experiments presented in this paper may be summarized as follows:

  1. 1.Observations were made upon the action of carbarsone on rat trichomonads in vivo utilizing some 550 rats. All the animals were infected with a culturable trichomonad, probably T. parva, but T. muris was also present in some of the animals.
  2. 2.It was found that a quantity of carbarsone of 150 mgm. per kilogram of body weight was the minimal effective dose when given by mouth to rats each day for five consecutive days.
  3. 3.By subcutaneous injection the minimal curative dose was larger, 200 mgm. per kilogram of body weight for five consecutive days.
  4. 4.A single dose of the arsenical, 1000 mgm. per kilogram of body weight, was found to be curative when administered orally or intravenously.
  5. 5.The cures of the trichomonad infection produced by carbarsone in the rat were considered to be “permanent.”
  6. 6.The presence of carbarsone was demonstrated in the feces and contents of the large intestine of rats to which the drug was given orally.
  7. 7.It was found that solutions injected by catheter into the stomach of rats which had been without food for twelve hours reached their ceca in half an hour and were uniformly distributed in it in two hours, and that trichomonadicidal quantities of carbarsone were occasionally present in the large intestine of these animals as long as forty-eight hours after its oral administration.
  8. 8.The percentage concentration of carbarsone in the large intestine after oral administration was estimated to be 0.47 when the quantity given was 150 mgm. per kilogram of body weight, and 3.2 when the dose given was 1000 mgm. per kilogram of body weight. In these dilutions, the trichomonads in regard to the time required for their destruction, behaved so similarly to those exposed to corresponding concentrations of the arsenical in vitro, that it was concluded that the action of carbarsone in vivo and in vitro is probably the same, i.e., direct.

Author Notes

The writer desires to thank Drs. Robert Hegner and Justin Andrews for their suggestions in carrying out this work and assistance in preparing the manuscript.