Ethidium bromide: pharmacokinetics and efficacy against trypanosme infections in rabbits and calves.
[14C]ethidium bromide has been used to determine drug levels in tissues and body fluids of rabbits and calves following intramuscular injection. Uninfected and Trypanosoma brucei- or Trypanosoma congolense-infected animals were studied. Blood and tissue fluid level reached a maximum with 1 h and then fell rapidly; after 96 h 80-90% of the radioactivity injected had been excreted, approximately one third in urine and two thirds in faeces. By 1 h after injection of 1 mg [14C]ethidium/kg into a T. congolense-infected calf, 70-80% of the radioactivity in blood was found to be bound to trypanosomes. Doses of 1 or 10 mg/kg were found not to be curative for T congolense or T. brucei infections in rabbits: drug treatment resulted in a period of sub-patent parasitaemia which was always followed by a relapse. Examination of the prophylactic action of ethidium in rabbits showed that the drug extended the pre-patent period following trypanosome inoculation but provided no absolute protection. A period of "apparent' prophylaxis observed after drug treatment of infected rabbits has been correlated with the presence of anti-trypanosome IgG in the serum.
D000818:Animals; D001826:Body Fluids / Q000378:metabolism; D002417:Cattle; D004996:Ethidium / Q000097:blood / Q000378:metabolism* / Q000627:therapeutic use; D005243:Feces / Q000032:analysis; D011817:Rabbits; D014018:Tissue Distribution; D014345:Trypanosoma; D014346:Trypanosoma brucei brucei; D014353:Trypanosomiasis, African / Q000188:drug therapy* / Q000378:metabolism; D014354:Trypanosomiasis, Bovine / Q000188:drug therapy* / Q000378:metabolism
D004996:Ethidium