What Causes Stomach Pain After Taking Levodropropizina And Celestamine?

My mother is sick and we are in Mexico.She has had no fever but a troubling cough, aches and chills.She was given Levodropropizina, Levodropropizina, (both in liquid form) and Celestamine NS in tablet form. She is experiencing stomach pain. I want her to stop taking the Celestamine NS tablets since stomach pain appears to be a side effect. What benefits will she lose if she stops taking this pill?