Epilim Chrono Sodium Valproate Fosphenytoin Sodium
ModeratePhenobarbital, valproic acid and sodium valproate can each raise or lower the level of phenytoin (the active form of fosphenytoin) in your blood. It is hard to say which will happen in any one person. The effect also works the other way. Phenytoin can change the blood levels of phenobarbital, valproic acid and sodium valproate, and again the direction can't be predicted. If you are prescribed these together, your doctor may check your blood levels from time to time.
These medicines are often taken together with some care. Your doctor may change a dose, space them apart or check on you more often. Make sure your doctor and pharmacist know you take both.