Toxicological studies on the new veterinary antibiotic turimycin

The acute toxicity of turimycin investigated in several animal species and following different routes of administration is low. In mice the LD50 values range from 320 mk/kg after iv injection up to more than 3000 mg/kg when administered orally. When lethal or sublethal doses of turimycin were given, animals either developed clonic convulsions and died within 24 hr, or recovered completely. The main pharmacological effect of turimycin is a reversible, dose dependent decrease in the blood pressure after intravenous injection of 10 to 15 mg/kg in cats and dogs. This may be due to the negative inotropic and chronotropic effect on heart muscle (isolated atria of guinea-pigs) and to the spasmolytic effect on the smooth muscle (rat ileum). A temporary decrease of the renal filtration rate after administration of turimycin is probably caused by its influence on the blood pressure. In rats the hexobarbital sleeping time was increased after repeated administration of higher doses of turimycin. In a chronic study on dogs oral doses of 50 and 125 mg/kg of turimycin, given in capsules daily for 12 months, produced no functional or histopathological abnormalities.