Anticholinergic properties of brompheniramine, chlorpheniramine, and atropine in human nasal mucosa in vitro.

Brompheniramine and chlorpheniramine have anticholinergic activities, but the relative potency of these effects has not been well defined. The anticholinergic properties of brompheniramine, chlorpheniramine, and atropine were assessed in an in vitro model of human nasal mucosal glandular secretion. Methacholine was used as a cholinergic agonist to stimulate glandular secretion of 7F10-mucin. These drugs (0.01-1000 microM) or vehicle (saline) were added to explant cultures with and without 100 microM methacholine. 7F10-mucin concentrations were measured in culture supernatants after 2-hour incubations. The effective dose reducing methacholine-induced secretion (ED50) was determined. ED50 was 0.25 microM for atropine, 4.10 microM for brompheniramine, and 4.63 microM for chlorpheniramine. None of the anticholinergic drugs changed spontaneous glandular exocytosis. Brompheniramine and chlorpheniramine are equipotent anticholinergic agents in human nasal mucosa in vitro. Atropine was 16 to 19 times more potent.