[Chemotherapeutic efficacy of trimethoprim-sulfamethoxazole (Bactrim) in experimental murine toxoplasmosis].

The chemotherapeutic efficacy of trimethoprim-sulfamethoxazole (Bactrim) in mice experimentally infected with Toxoplasma gondii was evaluated. The average survival days and survival rate of mice infected intraperitoneally with 1 x 10(5) trophozoites and treated with Bactrim were compared with those of untreated group. The hematologic findings of blood samples of experimental mice were observed for comparison of side effects between Bactrim and pyrimethamine (Daraprim), the latter of which has been one of the favorable drugs for the treatment of toxoplasmosis. The results are summarized as follows: Bactrim showed a strong evidence of potent anti-Toxoplasma activity. The survival rate of mice administered with 24 mg of Bactrim per mouse per day for 7 days, was 83.3 percent, and the rate was increased to 100 percent in mice administered with two-fold concentrated dose of the drug. The average numbers of white blood cells (W.B.C.) in the mouse groups treated with Bactrim or Daraprim were more increased than those only infected with T. gondi. The mice treated with Daraprim, however, showed remarkably decreased numbers of W.B.C. as compared with those treated with Bactrim. The average numbers of red blood cells (R.B.C.) and platelets both in the drug-treated and untreated T. gondii-infected mice were decreased as compared with normal mice. The numbers of R.B.C. in Daraprim-treated mice, however, were more decreased than in Bactrim-treated mice. The average levels of hemoglobin both in the drug-treated and untreated T. gondii-infected mice were decreased, compared with normal mice. But there was no difference in the levels of hemoglobin between Bactrim- and Daraprim-treated groups. In conclusion, trimethoprim-sulfamethoxazole (Bactrim) was proven to be effective and safe for the treatment of murine toxoplasmosis. The efficacy was comparable with pyrimethamine (Daraprim), but bone marrow depression was less severe with Bactrim treatment.