Effect of a single dose of montelukast sodium on methacholine chloride PC20

It is currently recommended that leukotriene modifiers (receptor antagonists and synthesis inhibitors) be withheld for a minimum of 24 h before direct bronchoprovocation testing, but there is little evidence to support this recommendation.

To examine the effect of a single oral dose of montelukast sodium 10 mg on airway response to methacholine chloride-induced bronchoconstriction.

A double-blind, placebo-controlled, randomized crossover trial was performed in 12 subjects with asthma whose methacholine chloride concentration causing a 20% decrease in the forced expiratory volume during the first second of exhalation (PC20) was 8 mg/mL or lower and a baseline forced expiratory volume during the first second of exhalation of 70% predicted or greater. Two-minute tidal breathing methacholine chloride inhalation challenges were performed 1 h and 25 h after both 10 mg montelukast sodium and identical-appearing placebo.

There were no significant differences in the methacholine chloride PC20 between active treatment and placebo at 1 h post-10 mg montelukast sodium (1.0 mg/mL versus 1.3 mg/mL; n=12; P=0.17, respectively) or at 25 h post-10 mg montelukast sodium (1.4 mg/mL versus 1.9 mg/mL; n=11; P=0.15, respectively).

A single dose of montelukast sodium did not affect methacholine chloride-induced bronchoconstriction measured after 1 h and 25 h.