Jason,
All of my doctors have assured me that Movicol/Miralax is safe to take long term. I plan to always have to take it although I have been able to greatly reduce the dose by taking an oat bran/prune juice/applesauce mixture nightly. You might try that. It's 1 cup of oat bran/1 cup of applesauce/ 1/4 cup of prune juice. I currently take 3 tablespoons of that mixture at bedtime. Good luck!