Pyrvinium pamoate lacks in vivo genotoxicity in the colon.

Pyrvinium pamoate, a widely used anthelmintic drug, has been previously tested for genotoxicity with equivocal results. Assays with bacterial or yeast test strains yielded positive results while in vitro tests with mammalian cells yielded negative results. In this study, the genotoxicity of pyrvinium was studied in vivo in the mouse colon, the therapeutic site of action of this agent. 1,2-Dimethylhydrazine (DMH), a colon carcinogen, was tested simultaneously as a positive control. The colonic nuclear aberration assay was used to determine genotoxicity. Pyrvinium delivered orally in three vehicles was not genotoxic in the murine colon, even at doses up to 12.5 times the recommended human dosage.