Non allergic nasal drip chronic. What is best treatment?

First generation. Antihistamines are effective due to their anticholinergic (drying) effect. The most popular is diphenhydramine. Unfortunately these medications are poorly tolerated due to their side effect of lethargy. Another class of medications you can try are topical nasal antihistamines. Azelastine has been shown in clinical trials to be effective for non-allergic rhinitis. This must be prescribed.