Resumen de Formoterol Concentrations in Blood and Urine: The World Anti-Doping Agency 2012 Regulations.
Kasper Eibye, Vibeke Backer, Jimmi Elers, Kim Dalhoff, Lars Pedersen, Peter Hemmersbach, John Henninge
AB Introduction: We examined urinary and serum concentrations of formoterol in asthmatic and healthy individuals after a single dose of 18 [mu]g inhaled formoterol and after repeated inhaled doses in healthy individuals. Results were evaluated using the World Anti-Doping Agency (WADA) 2012 threshold for formoterol. Methods: On the day of this open-label, crossover study, 10 asthmatic subjects who regularly used beta2-agonists and 10 healthy participants with no previous use of beta2-agonists received a single dose of 18 [mu]g formoterol. Further, 10 nonasthmatic participants inhaled 18 [mu]g formoterol every second hour until obtaining a total of 72 [mu]g, which is twice the maximum daily dose (36 [mu]g formoterol) permitted by the WADA. Blood samples were collected at baseline, 30 min, 1, 2, 3, 4, and 6 h after the first inhalation. Urine samples were collected at baseline, 0-4, 4-8, and 8-12 h after the first inhalation. Results: Median urine concentration, corrected for specific gravity, after the single-dose administration peaked during 0-4 h after inhalation at a maximum of 7.4 ng[middle dot]mL-1 in asthmatic subjects and 7.9 ng[middle dot]mL-1 in healthy subjects. Median urine concentration after repeated doses peaked during 4-8 h after inhalation of a total of 72 [mu]g formoterol at a maximum of 16.8 ng[middle dot]mL-1 in healthy participants. The maximum individual concentration of 25.6 ng[middle dot]mL-1 was found after inhalation of a total of 72 [mu]g formoterol. Conclusions: We found no significant differences in urinary and serum concentrations of formoterol between asthmatic and healthy subjects. We found high interindividual variability in the concentrations in all groups. Our data support the WADA 2012 urinary threshold of 30 ng[middle dot]mL-1 formoterol as being an adverse analytical finding.
