OTC antihistamines are overused. Constant marketing campaigns keep them front and center, and overuse may actually make sinus problems worse. Antihistamines are for “histaminic” or hay fever-like symptoms, which are itchy water eyes, sneezing, and rhinorhea (or what some used to term “catarrh”).

If you do not have these type of symptoms, then antihistamines can actually “gum up” the works, causing thickening and higher viscosity of the sinonasal secretions.