Rafoxanide is a halogenated salicylanilide. It 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. It binds more strongly to blood proteins, and therefore remain in the blood for longer periods.
Rafoxanide is active mainly against adult stages of liver flukes in cattle, sheep, goats and horses. It has lower efficacy against immature flukes may be due to the high protein binding of the drug in the blood. But it has high activity against 6-wk-old flukes in cattle and sheep, by affecting them either at the time of administration or, more probably, by persisting in blood until the flukes start to ingest blood and become exposed to higher drug concentrations.
It is also active against gastrointestinal nematodes (Haemonchus, Bunostomum, Oesophagostomum and Gaigeria species) and against the sheep nasal bot fly (Oestrus ovis).