Salbutamol Tolerance Onset

Salbutamol: Tolerance to Bronchoprotection vs. Methacholine: Time Course of Onset

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.

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