Influence of zafirlukast and loratadine on exercise-induced bronchoconstriction.
BACKGROUND
Airway obstruction induced by physical exercise is a common feature in asthma, and conventional treatments do not offer optimal protection. There is thus a need for additional therapies for optimal control of exercise-induced bronchoconstriction (EIB).


OBJECTIVE
The influence of treatment with the antihistamine loratadine and the antileukotriene zafirlukast alone and in combination on EIB was investigated. This combination has previously shown beneficial additive effects in allergen-induced bronchoconstriction.


METHODS
In a double-blind cross-over study loratadine (10 mg twice daily) and zafirlukast (80 mg twice daily) were evaluated alone and in combination in 16 nonsmoking patients with mild asthma, previously documented EIB, and airways hyperresponsiveness to histamine.


RESULTS
The mean +/- SE maximum decrease in FEV1 after a standardized exercise provocation was 21.6% +/- 3% after placebo, 22.8% +/- 3% after loratadine, 13.9% +/- 2% after zafirlukast (P <.05 vs placebo), and 10.3% +/- 2% after the combination of loratadine and zafirlukast (P <.05 vs placebo). Expressed as the area under the FEV1 percentage change versus time curve, the mean protection produced by zafirlukast and the combination of zafirlukast and loratadine was 57% and 65%, respectively, whereas loratadine alone had no significant protective effect. There was also no significant difference between the effect of zafirlukast alone or in combination with loratadine.


CONCLUSIONS
The study confirmed the beneficial effect of a leukotriene receptor antagonist in EIB but failed to obtain evidence that H1-receptor antagonism alone or together with the cysteinyl-leukotriene 1 receptor antagonist zafirlukast offers a protective effect.
Dahlén
Barbro
B
Division of Respiratory Medicine, Department of Medicine at Karolinska Hospital and Experimental Asthma and Allergy Research, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
Roquet
Annika
A
Inman
Mark D
MD
Karlsson
Osten
O
Naya
Ian
I
Anstrén
Gudrun
G
O'Byrne
Paul M
PM
Dahlén
Sven-Erik
SE
D001982:Bronchial Diseases / Q000188:drug therapy* / Q000209:etiology* / Q000503:physiopathology; D003251:Constriction, Pathologic; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D015444:Exercise; D005541:Forced Expiratory Volume / Q000187:drug effects; D006634:Histamine H1 Antagonists / Q000627:therapeutic use*; D006801:Humans; D007211:Indoles; D020024:Leukotriene Antagonists / Q000627:therapeutic use*; D017336:Loratadine / Q000627:therapeutic use*; D048448:Phenylcarbamates; D013449:Sulfonamides; D014105:Tosyl Compounds / Q000627:therapeutic use*
D006634:Histamine H1 Antagonists; D007211:Indoles; D020024:Leukotriene Antagonists; D048448:Phenylcarbamates; D013449:Sulfonamides; D014105:Tosyl Compounds; D017336:Loratadine; C062735:zafirlukast