Inhaled salbutamol and doping control: effects of dose on urine concentrations.

Objective: The present study was designed to examine the dose-response relationship of inhaled salbutamol and its concentration in the urine while resting at various times after inhalation, and to compare these values against the current World Anti-Doping Code limits.

Design: An interventional, repeated-measures design.

Setting: Sport Medicine Clinic, University of British Columbia (Vancouver, Canada).

Participants: Eight healthy, nonasthmatic males participated in this study (age = 28 +/- 6 years, height = 179.4 +/- 5.1 cm, and weight = 77.4 +/- 5.4 kg).

Intervention: Administration of three different doses of inhaled salbutamol (800, 400, and 200 microg) in a randomized fashion separated by at least 72 hours.

Main Outcome Measurement: Urine concentration of nonsulphated salbutamol

Results: Urine concentrations were highly variable between subjects and increased as dose increased, with a significant difference noted between 800 and 200 microg at 30, 60, and 120 minutes after inhalation. Urine concentrations of salbutamol peaked at 60 minutes for all doses. No samples exceeded the doping criterion of 1000 ng/mL, and the maximum value observed was 904 ng/mL.

Conclusion: These results indicate that after inhalation of doses up to 800 microg, urinary concentrations of salbutamol are well below the limits used in doping control.