Abstract
Benzimidazole derivatives act by interfering with metabolic pathways. Parbendazole has been shown to exhibit a broad-spectrum Anthelmintic activity. This compound is the most potent of a series of substituted 2-amino derivatives and is active against a wide variety of animal nematodes. The drug showed marked activity against third stage larvae that were located in the muscular tissue. It inhibits monoamine oxidase in animal nematodes. The drug was used with good effects against the common parasites of cattles, pigs, and horses. It acts quickly reaching peak blood levels 6-8h after administration. Its use in pregnant animals is contraindicated because of its teratogenicity; the defects are largely skeletal. Like other benzimidazoles, it suffers from the problem of resistance developing in the resident worm population if it is used persistently. The mode of action is not clearly delineated, but the following effects on the parasite, such as degeneration of microtubules, inhibition of glucose transport and uptake, interference with energy production, inhibition of fumarate reductase, ovicidal, cytoplasmic microtubules disappear in tegumentary and intestinal cells, secretory processes are discussed in this chapter. The toxicity of parbendazole in different doses was investigated with a group of animals. The side effects observed with the Anthelmintic were laxation (soft dung, diarrhea), anorexia, and listlessness.