My son, who is almost 15 yrs old and has developmental disabilities, has had seizures since he was 2.5 years old. His seizures have gotten really bad since puberty hit 5 years ago and they keep changing. He has failed over 8 medications, and the ones that he is on now seem to be adding new types of seizures. My question is, how is it that a medication used to TREAT a certain type of seizure, causes them instead? He is on Trileptal 15ml twice a day and Onfi 2 ml am and 3 ml pm. He has been having sporadic subclinicial seizures and atypical absent seizures since starting Onfi.