I Am Helping A Friend With Her Many Meds. She

I am helping a friend with her many meds. She was just switched from Pristiq to Fetzima. She is on Abilify, oxycontin and trazadone. as wellas other maintenance meds. ai am concerned about interactions since I know most of her meds are powerful. ai help her because she has some possible demntia and forgetfullness. I am a retired RN and have been organizing her meds to keep her from forgetting them. What would you expect any new problems with the new med.