Salicylanilides, Substituted Phenols, and Aromatic Amide
The members of this chemical grouping include salicylanilides (brotianide, clioxanide, closantel, niclosamide, oxyclozanide, rafoxanide), substituted phenols (bithionol, disophenol, hexachlorophene, niclofolan, menichlopholan, nitroxynil), and the aromatic amide diamfenetide (diamphenethide). All members of these groups are active mainly against adult stages of liver flukes. They are used extensively against fasciolosis and haemonchosis in sheep and cattle. Diamfenetide is unique in that it has exceptionally high activity against the youngest immature stages of the liver fluke in sheep, with a diminution of activity as the flukes mature. The lowered efficacy of a number of the salicylanilides and substituted phenols against immature flukes may be due to the high protein binding of these drugs in the blood. A number of these compounds, however, appear to have activity against 6-wk-old flukes in cattle and sheep, by affecting them either at the time of administration or, more likely, by persisting in blood until the flukes start to ingest blood and become exposed to higher drug concentrations. They are all given PO, except nitroxynil, which is typically given SC.
Niclosamide is used PO to treat cestode infections (Dipylidium caninum and Taenia spp) in dogs.