I use a year-round non-steroid nasal spray Azalastine (OTC brand name AstePro, but much cheaper in generic on my Medicare Part D.) to control post-nasal drip. This not only relieved my post-nasal drip, and the accompanying cough/raw throat, but alleviated the heartburn/indigestion I used to get. Ironically, everyone assume I had reflux, but all tests said "no" and this proved it.

During allergy seasons, I then add an over-the-counter antihistamine tablet called Xyzal (levocetiritzine). It is not as drying as most others I have tried, and does not aggravate my bronchospasms.

Have you tried a nasal spray to control the post-nasal drip? They are often less drying than an oral antihistamine.