Closantel is a broad-spectrum antiparasitic agent used against several species and developmental stages of trematodes, nematodes and arthropods. The anti-trematode activity of closantel is mainly used against liver fluke. The anti-nematode and anti-arthropod activity is especially used against those species which feed on blood or plasma.
Closantel is an uncoupler of the mitochondrial oxidative phosphorylation resulting in inhibition of the ATP-synthesis. This induces a dramatic change in the energy metabolism which finally leads to the death of the parasite.The drug is widely used in sheep and cattle and can be used either parenterally (s.c. or i.m.) or orally for both prophylactic and therapeutic purposes and is available as drench, bolus and injectable formulations. Closantel has also been combined with mebendazole and several other benzimidazoles in drench formulations for sheep and with levamisole in a bolus for cattle.