Risperidone and Topiramate interaction

Topiramate Oral RISPERDAL administered at doses from 1–6 mg/day concomitantly with topiramate 400 mg/day resulted in a 23% decrease in risperidone C max and a 33% decrease in risperidone AUC 0–12 hour at steady state.

Carbamazepine and other enzyme inducers decrease plasma concentrations of risperidone.

Carbamazepine and Other CYP 3A4 Enzyme Inducers Carbamazepine co-administration with oral RISPERDAL decreased the steady-state plasma concentrations of risperidone and 9-hydroxyrisperidone by about 50%.

Co-administration of other known CYP 3A4 enzyme inducers (e.g., phenytoin, rifampin, and phenobarbital) with risperidone may cause similar decreases in the combined plasma concentrations of risperidone and 9-hydroxyrisperidone, which could lead to decreased efficacy of RISPERDAL CONSTA treatment.

At the initiation of therapy with carbamazepine or other known hepatic enzyme inducers, patients should be closely monitored during the first 4–8 weeks, since the dose of RISPERDAL CONSTA may need to be adjusted.

Because of the potential of topiramate to cause CNS depression, as well as other cognitive and/or neuropsychiatric adverse reactions, TROKENDI XR should be used with extreme caution if used in combination with alcohol and other CNS depressants [see Contraindications (4) and Warnings and Precautions (5.7) ].

CNS Depressants Concomitant administration of topiramate with other CNS depressant drugs or alcohol has not been evaluated in clinical studies.