Anticonvulsant medications , such as valproate ( depakote ) or carbamazepine ( tegretol ) , also can have mood-stabilizing effects and may be especially useful for difficult-to-treat bipolar episodes .
Coadministration of carbamazepine decreases steady-state plasma concentrations of risperidone and its active metabolite , 9-hydroxyrisperidone , by approximately 50 % ; plasma concentrations of carbamazepine did not appear to be affected .
Patients should be monitored during the first 4 to 8 weeks of treatment with risperidone and carbamazepine or other enzyme inducers ; dose increases or additional oral risperidone may need to be considered .