Ricobendazole, also known as albendazole S-oxide, is a broad-spectrum benzimidazole anthelmintic. Its main use is for protecting livestock against nematode parasites. Ricobendazole is the active sulfoxide metabolite of albendazole.
Like mebendazole, ricobendazole inhibits tubulin polymerization.
Ricobendazole is produced in many species and in human liver when albendazole undergoes first-pass metabolism by the enzymes albendazole monooxygenase (sulfoxide-forming) (a cytochrome P450 oxidase) or albendazole monooxygenase (a flavin-containing monooxygenase.