How Can Allergic Rhinitis With Postnasal Drip And Cough Be Treated?

Dr. Grief, My postnasal drip cough is causing me grief...lol...I have allergic rhinitis which causes postnasal drip cough...sinus rinse helps which I do before I go to bed...but, end up stuffed up...coughing in bed. What can I do for relief...would vaporizer help? The cold makes it worse. Thank you... Cheryl