perampanel and stiripentol

New-generation antiepileptic drugs as perampanel, rufinamide and stiripentol emerged as alternatives in chronic epilepsy polytherapy. Hence, their metabolic stability and potential involvement in relevant drug-drug interactions (DDI) are of great clinical interest, being HepaRG cells herein used as an in vitro human model. To characterize their metabolic stability profiles, HepaRG cells were incubated with perampanel (1 μM), rufinamide (100 μM) or stiripentol (5 μM) for 12-h. HepaRG cells, pretreated with known CYP450 isoenzymes inducers (rifampicin, phenytoin, phenobarbital, omeprazole and carbamazepine), were also incubated with perampanel, rufinamide or stiripentol to assess possible DDI mediated by CYP450 induction. Results suggest a considerable decrease in perampanel and stiripentol concentrations over 12-h; contrary, rufinamide concentrations did not variated. Cells pretreatment with all inducers significantly decreased stiripentol concentrations (between 20.3% and 31.9%), suggesting a considerable potential for DDI. Rufinamide concentrations only decreased when preincubated with rifampicin and with the highest tested concentrations of the remaining inducers. Perampanel levels decreased with rifampicin, carbamazepine and phenobarbital, supporting the involvement of CYP3A4-mediated metabolism. Besides relevant information concerning the metabolic stability profile and potential DDIs of the new antiepileptics here studied, it was also reinforced the HepaRG cells suitability as a reliable in vitro model to foresee in vivo metabolism in humans.

Topics: Anticonvulsants; Carbamazepine; Cytochrome P-450 Enzyme Inducers; Dioxolanes; Drug Interactions; Humans; Nitriles; Phenobarbital; Pyridones; Rifampin; Triazoles

Stiripentol is an orphan drug successfully used in combination with valproate and clobazam in the treatment of Dravet syndrome. Perampanel has also been added by experts. In this retrospective study, we investigated the influence of stiripentol on perampanel serum levels by using the doses and corresponding perampanel serum levels of 10 patients. The impact of stiripentol on the perampanel serum levels was significant as shown in a linear regression analysis, with perampanel serum levels increasing linearly with the stiripentol doses. We conclude that dose adjustments of stiripentol and perampanel when administered together, should be done carefully to avoid side effects or even severe intoxication. Hence, perampanel serum level monitoring seems advisable.

Topics: Adult; Anticonvulsants; Dioxolanes; Drug Therapy, Combination; Drug-Related Side Effects and Adverse Reactions; Epilepsies, Myoclonic; Female; Humans; Male; Nitriles; Pyridones