Salbutamol Tolerance Onset

Overview

Overuse of inhaled bronchodilator beta agonist medication results in a loss of effectiveness (i.e. tolerance). This has been shown for the short acting beta agonist salbutamol and the long acting beta agonist salmeterol. Tolerance to salmeterol is present within 24 hours. The onset of tolerance to salbutamol is not known.

Full Title of Study: “Salbutamol: Tolerance to Bronchoprotection vs. Methacholine: Time Course of Onset”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Crossover Assignment
    • Primary Purpose: Basic Science
    • Masking: Triple (Participant, Investigator, Outcomes Assessor)
  • Study Primary Completion Date: March 2012

Interventions

  • Drug: salbutamol
    • 200mcg twice daily for a total of 7 doses
  • Drug: Placebo
    • 200mcg twice a day for a total of 7 doses (3.5 days).

Arms, Groups and Cohorts

  • Active Comparator: salbutamol
  • Placebo Comparator: placebo
    • 200mcg twice daily for a total of 7 doses

Clinical Trial Outcome Measures

Primary Measures

  • Airway responsiveness as a measure of salbutamol bronchoprotection
    • Time Frame: ten minutes post 200mcg salbutamol on day 1
    • Regular use of salbutamol results in loss of bronchoprotection. The primary outcome is to determine the onset of this tolerance.
  • Airway responsiveness as a measure of salbutamol bronchoprotection
    • Time Frame: ten minutes post 200mcg salbutamol on day 3
    • Regular use of salbutamol results in loss of bronchoprotection. The primary outcome is to determine the onset of this tolerance.
  • Airway responsiveness as a measure of bronchoprotection. The primary outcome is to determine the onset of this tolerance.
    • Time Frame: ten minutes post 200mcg salbutamol on day 5
    • Regular use of salbutamol results in loss of bronchoprotection. The primary outcome is to determine the onset of this tolerance.
  • Airway responsiveness as a measure of salbutamol bronchoprotection
    • Time Frame: ten minutes post 200mcg salbutamol on day 7
    • Regular use of salbutamol results in loss of bronchoprotection. The primary outcome is to determine the onset of this tolerance.

Participating in This Clinical Trial

Inclusion Criteria

  • male or female – 18 to 65 years of age – non smoker – beta agonist naive for at least 14 days – baseline FEV1 at least 70% predicted – no respiratory tract infection or allergen exposure (if atopic) within 4 weeks of visit 1 Exclusion Criteria:

  • poorly controlled asthma – pregnant or lactating women

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 65 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • University of Saskatchewan
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Donald W Cockcroft, MD, Principal Investigator, University of Saskatchewan

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