Inhibition of CYP450 isoenzyme CYP2C19 and CYP3A4 may provoke pharmacokinetic interactions (inhibition of their hepatic metabolism) with phenobarbital, primidone, phenytoin, carbamazepine, clobazam (See, section 4.2), valproate (See, section 4.2), diazepam (enhanced myorelaxation), ethosuximide, and tiagabine.