Praziquantel is a pyrazinoquinoline compound originally developed for the treatment of schistosomiasis but has been found to have a wide spectrum of anthelminthic activity. Praziquantel is a racemate but the R (+) enantiomer is solely responsible for its antiparasitic activity. It is active against trematodes (all Schistosoma species pathogenic to man, Paragonimus westermani, and Clonorchis sinensis) and cestodes (Taenia saginata, Taenia solium, Hymenolepis nana and Diphyllobothrium latum).
Praziquantel is on the World Health Organization’s List of Essential Medicines, a list of the most important medications needed in a basic health system. Praziquantel is not licensed for use in humans in the UK; it is, however, available as a veterinary anthelmintic, and is available for use in humans on a named-patient basis.