Reduced bioavailability of atenolol in man: the role of bile acids

The effect of bile acids on atenolol bioavailability was assessed using a randomised two-way cross-over study in eight healthy volunteers. Single dose kinetics were studied in fasted subjects using either Tenormin® or a preparation of atenolol containing bile acids. The co-administration of bile acids with atenolol resulted in a 30% reduction in AUC and a 28% reduction in Cmax compared to Tenormin®. No significant differences in tmax or t12 were detected. The potential clinical implications of the interactions between atenolol and bile acids in vivo are discussed, together with a possible explanation for the observed effects of food on atenolol bioavailability.