Flubenol contains the active substance flubendazole, while Panacur contains fenbendazole. Both drugs have a similar mode of action. Due to disruption of the metabolism or the digestive system the planarians will eventually starve. Treatment with either medication should be repeated after approximately two weeks as they have no effect on planarian eggs. Thus, at the end of the "breeding season" newly hatched planaria are directly killed.
Unfortunately, both Flubenol and Panacur have a negative impact on the ecosystem in the aquarium. Flubenol kills all types of snails in the aquarium and the active substance is stored in the substrate for several months. Snails can only be re-introduced into the tank after a very, very long time. Panacur harms mostly snails like Neritina and Clithons. Red rimmed Melania, staghorn- and Physidae seem to be more likely to survive a treatment.. Again, the active ingredient remains in the substrate and thus inhibits a restocking in the near future. If Panacur is overdosed, it can also lead to deformities and reproductive disorders in shrimp.