Onset of action of a topical antihistamine as assessed by histamine challenge-induced plasma exudation responses.

BACKGROUND

Although usually administered orally, antihistamines are available also for topical use in allergic rhinitis. Information on onset of action of these drugs is incomplete.

OBJECTIVE

To examine onset of action of topical cetirizine-dinitrate on plasma exudation evoked by repeated nasal histamine challenges.

METHODS

A liposome formulation of cetirizine-dinitrate (2.44 mg per nasal cavity) was delivered via a nasal spray device as 2 consecutive actuations per nasal cavity in a placebo-controlled design. The nasal mucosal surface was challenged and lavaged with a histamine solution (100 microg/mL) 5, 15, 25, and 55 minutes after each treatment. In addition, the mucosa was lavaged with saline before each treatment. The lavage fluid levels of alpha2-macroglobulin were measured as an index of mucosal exudation (luminal entry) of plasma.

RESULTS

Histamine produced significant increases in nasal lavage fluid levels of alpha2-macroglobulin at all observation points (5 through 55 minutes after treatment). Nasal cetirizine-dinitrate significantly inhibited this response at 5 and 15 minutes after treatment.

CONCLUSIONS

The effect of topical cetirizine-dinitrate, as established by histamine challenge-induced mucosal exudation of plasma, has an early onset (ie, within 5 to 10 minutes).