Regarding Praziquantel, when using "pure" powder, much depends on the way it was processed and molecular weight.
On an avg., 1/4 teaspoon of the typical (this varies though) fine powder = 380mg. If one uses that conversion and weighs 150 lbs (68kg), then at the avg prescribed 25mg per kg weight per dose would be 68kg times 25mg = 1700 mg per dose or 1700/380= 1 1/8 teaspoon per dose (times 3 or 4 times per day). 25mg/kg every 8 hours a good min. dose schedule, so 5,100 mg per day.
Likely many are underdosing - just an obsevation