Pharmacokinetics of nebulized and oral procaterol in asthmatic and non-asthmatic subjects

Given the high prevalence of asthma in elite athletes, beta2-agonists are among the most used drugs in competitive sports. Numerous studies have investigated the pharmacokinetics of different beta2-agonists while limited data exist on procaterol. We investigated serum and urine concentrations of procaterol when administered as nebulization and tablets in asthmatic and non-asthmatic subjects. Methods: Ten asthmatic and 10 non-asthmatic men underwent two visits. 1. visit 4μg procaterol as nebulization. 2. visit 0,1 mg procaterol as tablet. Blood and urine samples were collected prior to and after administration. Results: No differences were observed in serum and urine procaterol between the groups after nebulized administration. However, serum AUC tended (P=0.08) to be lower for the asthmatic group (1.21±0.35 vs. 2.23±0.70 ng/ml•min). After oral administration the asthmatic group showed higher serum procaterol (P<0.05) after 6 h (0.03±0.01 vs. 0.02±0.01) and serum AUC tended (P=0.09) to be higher (18.80±2.19 vs. 12.86±4.07 ng/ml•min). After oral administration urine concentrations were higher (P<0.05) for the asthmatic group after 4 h with (52.99±9.87 vs. 33.78±10.69 ng/ml) and without (47.29±12.14 vs. 27.74±8.78 ng/ml) adjustment for USG and tended (P=0.06) to be higher after 8 h when unadjusted for USG (39.13±9.32 vs. 15.25±4.83 ng/ml). Conclusion: Our data showed large variations in the serum and urine concentrations of asthmatics and non-asthmatics when procaterol was administrated as nebulization or as tablets. Urine concentrations of oral procaterol were markedly higher than after nebulization. These findings are relevant for WADA in regard to doping control of procaterol.