[Influence of montelukast on inhalational bronchial allergen provocation]

Leukotrienes are potent bronchoconstrictive and proinflammatory mediators in bronchial asthma. A randomized, cross-over study on 16 subjects assigned to two groups investigated whether premedication with the leukotriene antagonist montelukast (10 mg daily for 21 days) has a relevant effect on inhalational bronchial allergen provocation.

Allergens were inhaled by atomizing commercial provocation solutions in dilutions of 1 : 1000, 1 : 100, 1 : 50, 1 : 10 and 1 : 5 with a nebulizer (Pari). The allergen dose was escalated every 20 minutes until the positive criteria (20 % fall in FEV1, doubling of oscillatory resistance) were met. The provocation tests were performed on days 1, 21 and 42 of the study.

An allergen protective effect of variable magnitude (PD20 increased by a factor of 1.6 to 21) was observed in 12 of the 16 subjects following provocation with pollen and mite allergens. The mean for all 16 patients showed a highly significant increase (p = 0.0005) by a factor of 4.3. The extent of allergen protection cannot be predicted in individual cases and is independent of the chosen allergen and the PD20 without montelukast. However, a significant correlation (p = 0.0016) was found between unspecific bronchial hyperreactivity (histamine) and the PD20. The allergen protective effect of montelukast decreases with increasing unspecific hyperreactivity.

We recommend that medication with montelukast be discontinued before allergen provocation because it cannot be predicted in individual cases whether and to what extent montelukast suppresses the immediate reaction following inhalational bronchial allergen provocation.