Regular blood levels not essential. Also considered useful in the treatment of infantile spasms. Can make myoclonic epilepsy worse. Drowsiness, sedation, difficulty concentrating, mood changes may occur. Less frequently double vision, weight gain, nausea.
Side effects tend to decrease with time.
Does not interfere with effectivness of the oral contraceptive. Available in 25,50,100 or 200mg tablets. Must be introduced slowly to prevent rash. Regular blood levels not essential. Recent worldwide experience suggests it is more effective in the treatment of refractory generalised epilepsies.