Lamictal side effects

I have been on Lamictal 100mg for awhile now as a mood stabalizer. Since I am Keppra and the two are in the same catagory, my neurologist wants to up it and eventually get me off the Keppra. Make me happy and seizure free too. Yeah! Except now I have gone up to 150mg AM and 150mg PM. I am so constpated. Increased my fiber, fluids, exercise..... Has anyone else had this happen and if so does it go away????? Thanks in advance.

I was on Lamictal. I didnt get constipated on it but I ate so much fruits and vegetable (70% of my diet) I ended up developing a horrible allergic reaction to it and had to stop after 2 months.