Carbamazepine markedly reduces the
serum levels of
praziquantel by 90%, but whether this results in neurocysticercosis treatment failures is unclear; one study found that concurrent use was still effective for neurocysticercosis.
When treating systemic worm infections such as neurocysticercosis some authors advise increasing the
praziquantel dosage from 25 to 50 mg/kg if
carbamazepine is being taken, but in one study this dose was not effective. Note that the manufacturers current recommended dose of
praziquantel for neurocysticercosis is 50 mg/kg daily in 3 divided doses. The interaction with
carbamazepine 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).