Have you tried azelastine nasal (over the counter now) twice a day to see if that helps the night time coughing at all? It takes a few days to build up but it did seem to help me somewhat. It's for allergies and vasomotor (sp?) rhinitis. I get more coughing and mucus when smells bother me...just a thought. Hairspray sends me into an all day coughing up stuff event for example.