The influence of exercise and dehydration on the urine concentrations of salbutamol after inhaled administration of 1600 μg salbutamol as a single dose in relation to doping analysis

The present study investigated the influence of exercise and dehydration on the urine concentrations of salbutamol after inhalation of that maximal permitted (1600 mu g) on the 2015 World Anti-Doping Agency (WADA) prohibited list. Thirteen healthy males participated in the study. Urine concentrations of salbutamol were measured during three conditions: exercise (EX), exercise+ deehydration (EXD), and rest (R). Exercise consisted of 75 min cycling at 60% of VO2max and a 20-kmtime-trial. Fluid intakewas 2300, 270, and 1100mLduringEX, EXD, and R, respectively. Urine samples of salbutamolwere collected0-24h after drugadministration. Adjustment of urine concentrations of salbutamol to a specific gravity (USG) of 1.020 g/mLwas compared with no adjustment. The 2015WADAdecision limit (1200 ng/mL) for salbutamolwas exceeded in 23, 31, and 10% of the urine samplesduringEX, EXD, and R, respectively, when unadjusted for USG. When adjusted for USG, the corresponding percentages fell to 21, 15, and 8%. During EXD, mean urine concentrations of salbutamol exceeded (1325 +/- 599 ng/mL) the decision limit 4 h after administrationwhen unadjusted for USG. Serum salbutamol Cmax was lower (P<0.01) for R(3.0 +/- 0.7 ng/mL) than EX(3.8 +/- 0.8 ng/mL) and EXD(3.6 +/- 0.8 ng/mL). AUC was lower for R (14.1 +/- 2.8 ng/mL.h) than EX (16.9 +/- 2.9 ng/mL.h)(P<0.01) and EXD (16.1 +/- 3.2 ng/mL h)(P<0.05). In conclusion, exercise and dehydration affect urine concentrations of salbutamol and increase the risk of Adverse Analytical Findings in samples collected after inhalation of that maximal permitted (1600 mu g) for salbutamol. This should be taken into account when evaluating doping cases of salbutamol. Copyright (C) 2015 John Wiley & Sons, Ltd.