Single dose desloratadine and montelukast and allergen-induced late airway responses

¹ Dept of Medicine (Pharmacology and Respirology), University of Saskatchewan, Saskatoon, Saskatchewan, Canada
² Dept of Medicine, McMaster University, Hamilton, Ontario, Canada
³ Institut de cardiologie et de pneumologie de l'Universite Laval, Hopital Laval, Quebec City, Quebec, Canada

^* To whom correspondence should be addressed. E-mail: beth.davis{at}usask.ca.

	Abstract

Montelukast and desloratadine synergistically inhibit the allergen-induced early asthmatic response. Montelukast suppresses the allergen-induced late asthmatic response but there are no reports on the effect of desloratadine or the combination on the allergen-induced late asthmatic response.

Ten atopic asthmatics completed a multi-center, randomised, double-blind, crossover study comparing single dose placebo, 5mg desloratadine, 10mg montelukast, and the combination administered 2 hours prior to allergen inhalation challenge. Methacholine challenges were performed 24 hours pre and post allergen challenge. Exhaled nitric oxide measurements and sputum inflammatory cell counts were also assessed.

All active treatments significantly decreased the late asthmatic response area under the curve. Combination therapy provided the greatest inhibition compared to desloratadine and montelukast. Montelukast was non-significantly better than desloratadine and not as effective as combination. There was a trend toward a decrease in airway responsiveness following montelukast and combination. Montelukast, but not desloratadine or the combination, decreased eNO 24 hours post allergen. The allergen-induced increase in sputum eosinophils was significantly suppressed at 7h with desloratadine and combination therapy and at 24h with montelukast and combination therapy.

Single dose, co-administration of desloratadine and montelukast administered 2 hours prior to allergen inhalation clinically abolished the late asthmatic response and eosinophil recruitment.