Further evidente for interethnic differences in the oral pharmacokinetics of meloxicam

Introduction: Meloxicam is a nonsteroidal anti-inflammatory agent used widely in therapeutics. It is mainly metabolised by the cytochrome P450 enzyme (CYP) 2C9, with minor involvement of CYP3A4. So far, no information on the oral pharmacokinetics of this drug in adult Mexicans is available. The purpose of this study was to evaluate the oral pharmacokinetics of meloxicam in Mexican subjects. Methods: Twenty-four healthy male subjects received an oral dose of meloxicam 7.5mg after fasting for 10 hours. Blood samples were drawn from a suitable forearm vein and plasma obtained. The meloxicam concentration was evaluated by a high-performance liquid chromatographic method and pharmacokinetic parameters were obtained by non-compartmental techniques. Pharmacokinetic parameters obtained in this study were compared with those reported under similar conditions in other populations in order to establish if interethnic differences in the pharmacokinetics of meloxicam exist. Results: After administration of meloxicam, plasma levels increased to a maximum concentration ([C.sub.max]) of 0.702 ± 0.027 (mean ± SEM) µg/mL with a time to reach [C.sub.max] of 4.77 ± 0.65h. The area under the plasma concentration versus time curve was 24.82 ± 1.23 µg x h/mL. The clearance was about 4.8 mL/min and the volume of distribution 9.8 ± 0.36L. When these parameters were compared with those reported in German and Indian subjects, a reduced clearance and volume of distribution were evident in Mexicans. However, clearance and volume of distribution obtained in this study were very similar to those reported in Chinese subjects. Conclusions: The oral pharmacokinetic parameters of meloxicam in healthy Mexican subjects compared with historic controls reported in other populations showed a reduced clearance and volume of distribution when compared with German subjects, whereas no differences between Mexican and Chinese subjects were observed. These results suggest that there are interethnic differences in the pharmacokinetics of meloxicam.