Evaluation of tolerance after continuous and prolonged oral administration of salbutamol to asthmatic patients.

Salbutamol (8 mg) was administered twice daily as a sustained release formulation to twenty-four asthmatic patients for up to four weeks under double-blind conditions. 2. The ability of bronchial smooth muscle to respond was determined by monitoring the response to salbutamol (200 mug) administered by aerosol at set intervals three times a week. 3. There was no evidence of diminishing response during the study period. 4. It is concluded that tolerance to salbutamol does not occur at therapeutic dose levels and that clinical observations of tolerance may be due to other factors.