Hi My Child Is 3 And A Half Years Okd,

Hi my child is 3 and a half years okd, she has been havig a very non stop cough for the past week now doctor have her butalin for mucus to come out in addition to suprax and decadron lately , but she is not getting any better everytime i give her the butalin she has a terrible non stop cough and end up vomiting sometimes 3 times per day , should i stop it or is this normal?