I have PND and use Allegra, Astelin and Flonase for it. I was on Protonix for years for reflux with coughing as my primary symptom. What finally worked for me was taking Prevacid twice a day.

If you aren't already familiar with it, you might search this board for LPR. It might give you some insight as to why you cough after eating. There are some really good posts on this topic.