which is a better cough med.?

which medicine is better for a cough for a 17 month old, shes on amoxil but its not helping with her cough, poly-tussin dm, rondec dm or cardec dm? I also just started her on her breathing treatments. But her cough wakes her up in the middle of the night and the antibiotics are not helping i figure i should give her a cough med., right?

[Jizi]

When I called my daughter's doctor asking her the same thing, she told me they took all cough medicine off the shelves for children 2 yrs of age and under, she pretty much told me no cough medicine is safe to give her. Keep a vaporizer in the same room as her, lots of liquids, etc.