Tetramisol-600 Bolus is a rapidly absorbed & carried to all parts of the body. Peak blood level occurs within an hour and tissue level persists for upto 5 days. The drug is excreted mainly through the feces and urine. 40% is excreted in the urine and 32% in the feces within 12 hours and consequently has a short withdrawal period of 3 days for meat and 1 day for milk. It is not, however recommended for dosing to lactating animals. Most nematodes are expelled within 24 hours. low level of the drug acts as ganglion stimulants and give rise to muscular paralysis in the parasite where as higher level interfere with carbohydrate metabolism. The blocking occurs at the site of fumerate reduction and succinate oxidation.