The utility of methacholine airway responsiveness measurements in evaluating anti-asthma drugs

MD Inman, AL Hamilton, HAM Kerstjens, RM Watson, PM O'Byrne*

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    56 Citations (Scopus)

    Abstract

    Background: Measurements of airway responsiveness are frequently used to evaluate anti-asthma drugs.

    Objective: This study investigated the utility of methacholine airway responsiveness measurements in evaluating anti-asthma medications, both in terms of a bronchoprotective effect and the ability to attenuate allergen-induced methacholine airway hyperresponsiveness.

    Methods: Methacholine airway responsiveness was measured as PC20 on two occasions (separated by 35 +/- 17 days, mean +/- SD) in 40 subjects with mild, stable asthma. Additional subjects had PC20 measurements made before and af ter administration of either inhaled salbutamol (200 mu g) (n = 20) or allergen inhalation challenge (n = 31).

    Results: The reproducibility of the methacholine PC20 with this method was high (intraclass correlation coefficient = 0.94), The average shift in PC20 after salbutamol was 4.11 doubling concentrations (SD = 1.08). On the basis of these results, a sample size of 12 subjects would be required to demonstrate a 1 doubling concentration difference in the bronchoprotective effect of two drugs with a 90% power. The average shift in PC20 after allergen was 1.29 doubling concentrations. On the basis of these results sind an estimated SD of 0.96, a sample size of 24 subjects would be required to demonstrate that a drug is effective in attenuating 50% of allergen-induced airway hyperresponsiveness with a 90% power:

    Conclusion: These results confirm the high reproducibility of methacholine PC20 measurements in subjects with mild, stable asthma and demonstrate its utility in evaluating the effects of anti-asthma drugs.

    Original languageEnglish
    Pages (from-to)342-348
    Number of pages7
    JournalJournal of Allergy and Clinical Immunology
    Volume101
    Issue number3
    Publication statusPublished - Mar-1998

    Keywords

    • airway responsiveness
    • asthma
    • reproducibility
    • bronchoprotection
    • allergen
    • ALLERGEN-INDUCED INCREASE
    • INDUCED BRONCHOCONSTRICTION
    • BRONCHIAL RESPONSIVENESS
    • SODIUM CROMOGLYCATE
    • INHALED SALBUTAMOL
    • MILD ASTHMA
    • RESPONSES
    • HISTAMINE
    • REPRODUCIBILITY
    • REACTIVITY

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