Status and emerging issues in the use of
praziquantel for treatment of human trematode and
cestode infections are briefly reviewed. Since
praziquantel was first introduced as a broadspectrum
anthelmintic in 1975, innumerable articles describing its successful use in the treatment of the majority of human-infecting trematodes and cestodes have been published. The target trematode and cestode diseases include
schistosomiasis,
clonorchiasis and
opisthorchiasis,
paragonimiasis, heterophyidiasis,
echinostomiasis,
fasciolopsiasis, neodiplostomiasis, gymnophalloidiasis,
taeniases,
diphyllobothriasis,
hymenolepiasis, and
cysticercosis. However, Fasciola hepatica and Fasciola gigantica
infections are refractory to
praziquantel, for which
triclabendazole, an alternative
drug, is necessary. In addition, larval
cestode infections, particularly
hydatid disease and
sparganosis, are not successfully treated by
praziquantel. The precise mechanism of action of
praziquantel is still poorly understood. There are also emerging problems with
praziquantel treatment, which include the appearance of drug resistance in the treatment of Schistosoma mansoni and possibly Schistosoma japonicum, along with allergic or
hypersensitivity reactions against
praziquantel treatment. To cope with and overcome these problems, combined use of drugs, i.e.,
praziquantel and other newly introduced compounds such as
triclabendazole,
artemisinins, and
tribendimidine, is being tried.