Pyrantel was first introduced as a broad-spectrum anthelmintic against GI nematodes of sheep and has also been used in cattle, horses, dogs, cats, and pigs. It is available as a citrate, tartrate, embonate, or pamoate salt.
Aqueous solutions are subject to isomerization on exposure to light, with a resultant loss in potency; therefore, suspensions should be kept out of direct sunlight. It is not recommended for use in severely debilitated animals because of its levamisole-type pharmacologic action.
Pyrantel is used PO as a suspension, paste, drench, or tablets. Both pyrantel and morantel are effective against adult gut worms and larval stages that dwell in the lumen or on the mucosal surface.
Ruminants:
Pyrantel tartrate is effective as a broad-spectrum anthelmintic in ruminants; however, its activity is mainly limited to the adult GI nematodes.
Horses:
Pyrantel is effective against adult ascarids, large and small strongyles, and pinworms. At double the recommended dose, it has limited activity against the ileocecal tapeworm Anoplocephala perfoliata.
Swine:
Pyrantel tartrate is used in swine to treat Ascaris and Oesophagostomum.
Dogs and Cats:
Pyrantel pamoate or embonate is effective against the common GI nematodes, except for whipworms. Oxantel, a phenol analogue of pyrantel, is combined with pyrantel in some anthelmintic preparations for dogs (and people) to increase activity against whipworms.
