Effects of single green tea ingestion on pharmacokinetics of nadolol in healthy volunteers
Shingen Misaka, Osamu Abe, Tomoyuki Ono, Yuko Ono, Hiroshi Ogata, Itaru Miura, Yayoi Shikama, Martin F. Fromm, Hirooki Yabe, Kenju Shimomura
Abstract
Aims The aim of this study was to investigate the effects of a single green tea (GT), administered concomitantly or 1 hour before nadolol intake on nadolol pharmacokinetics. Methods In a randomized 3‐phase crossover study, 11 healthy volunteers received an oral administration of nadolol with, or 1 hour after preingestion of brewed GT, or with water in a volume of 150 mL. Results Geometric mean ratio with 90% confidence interval for nadolol AUC 0–48 was 0.371 (0.303–0.439) with concomitant GT. In addition, ingestion of GT 1 hour before nadolol administration resulted in a significant reduction of nadolol AUC 0–48 with geometric mean ratio of 0.536 (0.406–0.665). There were no differences in time to maximal plasma concentration and renal clearance of nadolol among groups. Conclusion These results suggest that single concomitant ingestion of GT substantially decreases plasma concentrations of nadolol. Moreover, the reduction in nadolol bioavailability could persist for at least 1 hour after drinking a cup of GT.