title: Urine concentrations of oral salbutamol in samples collected after intense exercise in endurance athletes.
abstract: Our objective was to investigate urine concentrations of 8 mg oral salbutamol in samples collected after intense exercise in endurance athletes. Nine male endurance athletes with a VO2max of 70.2 ± 5.9 mL/min/kg (mean ± SD) took part in the study. Two hours after administration of 8 mg oral salbutamol, subjects performed submaximal exercise for 15 min followed by two, 2-min exercise bouts at an intensity corresponding to 110% of VO2max and a bout to exhaustion at same intensity. Urine samples were collected 4, 8, and 12 h following administration of salbutamol. Samples were analyzed by the Norwegian World Anti-doping Agency (WADA) laboratory. Adjustment of urine concentrations of salbutamol to a urine specific gravity (USG) of 1.020 g/mL was compared with no adjustment according to WADA's technical documents. We observed greater (P = 0.01) urine concentrations of salbutamol 4 h after administration when samples were adjusted to a USG of 1.020 g/mL compared with no adjustment (3089 ± 911 vs. 1918 ± 1081 ng/mL). With the current urine decision limit of 1200 ng/mL for salbutamol on WADA's 2013 list of prohibited substances, fewer false negative urine samples were observed when adjusted to a USG of 1.020 g/mL compared with no adjustment. In conclusion, adjustment of urine samples to a USG of 1.020 g/mL decreases risk of false negative doping tests after administration of oral salbutamol. Adjusting urine samples for USG might be useful when evaluating urine concentrations of salbutamol in doping cases.
authors.affiliation: Respiratory Research Unit, Bispebjerg University Hospital, Copenhagen, Denmark; Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Hostrup
authors.forename: Anders
authors.initials: A
authors.lastname: Kalsen
authors.forename: Michael
authors.initials: M
authors.lastname: Auchenberg
authors.forename: Sebastian
authors.initials: S
authors.lastname: Rzeppa
authors.forename: Peter
authors.initials: P
authors.lastname: Hemmersbach
authors.forename: Jens
authors.initials: J
authors.lastname: Bangsbo
authors.forename: Vibeke
authors.initials: V
authors.lastname: Backer
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000420:Albuterol / Q000008:administration & dosage / Q000652:urine*; D056352:Athletes; D001993:Bronchodilator Agents / Q000008:administration & dosage / Q000652:urine*; D004300:Doping in Sports; D005080:Exercise Test; D005188:False Negative Reactions; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D010807:Physical Endurance / Q000502:physiology; D015813:Substance Abuse Detection / Q000379:methods*; D013997:Time Factors; D055815:Young Adult
chemical_list: D001993:Bronchodilator Agents; D000420:Albuterol
keywords: athletes; doping; salbutamol; urine concentrations; urine specific gravity