Phenobarbital (and therefore probably primidone) markedly reduces the
serum levels of
praziquantel, but whether this results in neurocysticercosis treatment failures is unclear.
When treating systemic worm infections such as neurocysticercosis some authors advise increasing the
praziquantel dosage from 25 to 50 mg/kg if
phenobarbital is being used. Note that the manufacturers current recommended dose for
praziquantel for neurocysticercosis is 50 mg/kg daily in 3 divided doses. The interaction with antiepileptics is of no importance when
praziquantel is used for intestinal worm infections (where its action is a local effect on the worms in the gut).