Asthma
Conditions
Brief summary
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.
Interventions
DRUGsalbutamol
200mcg twice daily for a total of 7 doses
DRUGPlacebo
200mcg twice a day for a total of 7 doses (3.5 days).
Sponsors
University of Saskatchewan
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Airway responsiveness as a measure of salbutamol bronchoprotection | 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 bronchoprotection. The primary outcome is to determine the onset of this tolerance. | 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. |
Countries
Canada
Outcome results
None listed