Background: The aim of this study was to investigate the effect of the corticosteroids, the antihistamines, and the preservatives benzalkonium chloride (BKC) and potassium sorbate (PS) in intranasal medications on human nasal epithelial ciliary beat frequency (CBF). Methods: Primary ciliated epithelial cell cultures from the human nasal mucosa of chronic sinusitis patients were established. Changes in CBF of epithelial cell cultures treated/untreated with intranasal medications or preservatives were assessed using high-speed digital imaging methods. Results: Budesonide caused a rapid but reversible ciliostasis and showed no ciliotoxic effect at 10% dilution. Fluticasone propionate induced an irreversible ciliostatic activity and showed a reversible decrease in CBF at 10% dilution. Azelastine hydrochloride and levocabastine hydrochloride both induced a dose-dependent and irreversible decrease in CBF, although the ciliotoxic effect was not evident at 5% dilution. BKC resulted in an irreversible ciliostasis at 0.005 or 0.01% concentrations, whereas PS did not show any change in CBF at 0.12 or 0.24% concentrations. Conclusions: Crystalline BKC and BKC-containing intranasal medications, including fluticasone propionate, azelastine hydrochloride and levocabastine hydrochloride, but not PS or PS-containing intranasal budesonide spray, led to irreversible ciliostasis in human nasal epithelial cell cultures when applied at clinically relevant concentrations. (C) 2014 S. Karger AG, Basel