Effect of Chlorpheniramine on Airway Physiology and Symptoms during Natural Pollen Exposure

Abstract

Previous studies have documented the changes in airway physiology which accompany natural pollen exposure. This study was designed to determine the effect of chlorpheniramine (8 mg b.i.d.) on seasonal changes in airway physiology and symptoms. Pollen counts, eustachian tube (ET) function, nasal resistance, mucociliary transport, and nasal symptoms were assessed weekly before, during, and after ragweed pollen season in 15 chlorpheniramine-treated and 15 placebo-treated allergic rhinitis (AR) subjects in a double-blind protocol and in 10 untreated control (non-AR) subjects. In placebo-treated AR subjects, the degree of congestion, rhinorrhea, sneezing, ET dysfunction, and nasal obstruction closely tracked pollen counts. However, symptoms, ET obstruction, and nasal obstruction persisted well beyond the temporal peak in pollen counts. There were no changes in mucociliary transport or pulmonary function during pollen exposure. Compared to placebo, chlorpheniramine-treated subjects manifested significantly less (p < .05) seasonal sneezing and rhinorrhea, but similar degrees of nasal congestion, ET dysfunction, and nasal obstruction. Pollen-related changes in nasal physiology and symptoms were not detected in the non-AR subjects. These data document that chlorpheniramine significantly attenuated the seasonal increases in rhinorrhea and sneezing, but did not lessen the concommitant physiologic alterations or the increase in nasal congestion.