Evaluation of the urinary threshold concentration of formoterol in sports drug testing.

The use of formoterol in sports is allowed by inhalation at the maximum recommended therapeutic dose. Recently, a threshold concentration of 30 ng.mL(-1) was defined by the World Anti-Doping Agency (WADA) to distinguish between therapeutic and forbidden use of formoterol. The objective of this work was to evaluate that threshold concentration. Concentrations of formoterol were measured in urine samples collected after administration of 18 µg of inhaled formoterol to five healthy volunteers, and in samples collected in routine doping tests belonging to athletes having declared inhaled formoterol use. Formoterol was detected up to 8 h after administration in all volunteers with concentrations up to 19.6 ng.mL(-1) . From 28 routine samples, 27 had less than 10 ng.mL(-1) of formoterol and only in one of the samples the concentration was 25 ng.mL(-1) . Therefore, administration of formoterol by inhalation at the maximum dose allowed by WADA will not produce false positive results using a threshold concentration of 30 ng.mL(-1) , and the experience up to now in routine doping tests indicates that the probability of obtaining urines with concentrations greater than 30 ng.mL(-1) is close to nil. For this reason, sports authorities should re-evaluate the need of a threshold concentration for formoterol and its practical usefulness.