Hello Leslie,
I have never tried Trileptal, but, a lot of our meds have side effects that may or may not affect any one individual. If you chek our Drug Tab at top there are comments from other users of Trileptal that may prove helpful. But, since we all tend to react differently, your son may just be the 'odd' one who reacts that way to that med.

Thank Goodness the Dr is taking him off it.
Did the Doc run a blood test to chek his med Levels? If his system wasn't processing the med properly, it would show toxic levels, which Mite explain increase in seizures & changing Types.
In my Daughter's case meds weren't working & her seizure 'focal point' (where seizures originated) spread from one area to include the whole brain.

W/in 1-2 yrs.

Researchers theorize that our brain Teaches the rest of the brain to seize. Which is why it is important to achieve seizure control ASAP. But, we all know, seizure control is Iffy on any of our meds. It just depends on how our systems react to the med. It May take more than 1 med change to find the rite one for your son.
Are you keeping a Journal? If not, now, during his med change, would be a Good time to start. Read Journal Info under Tips.

Again, taking him off Trileptal IS a Good Thing!

I do Hope you will, Please, keep us posted. Know I care. HUGS!
Love Candi