It has been reported that the pharmacokinetics and pharmacodynamics of carvedilol vary between the S- and R- enantiomers. The aim of this study was to evaluate the pharmacokinetic characteristics of carvedilol for each enantiomer and apply this in clinical practice. Serum stereoselective concentrations of carvedilol were monitored in 60 Japanese inpatients who received a fixed dose of carvedilol. The concentrations were determined by high performance liquid chromatography (HPLC). Serum carvedilol concentration/dose of administered carvedilol ratios were determined for each enantiomer (R/D, S/D). The means±SD for R/D and S/D were 85.8±264.0 (10-3kg/L) and 29.0±78.2 (10-3kg/L), respectively. The mean for R/D tended to be larger than that for S/D (p=0.11), and the dispersion of R/D was significantly greater than that of S/D (p<0.01). Although a significant positive correlation was observed between R/D and S/D, a remarkable difference was observed in a few inpatients. These results suggest that the pharmacokinetics of carvedilol are different for each enantiomer. The monitoring of the stereoselective pharmacokinetics of carvedilol is therefore necessary to ensure proper use.
