Many thanks

Based on the dynamics of the two classes of drugs one would expect what William points out. Carlos may also want to consider respective blood levels in the patients presenting with bradycardia with this combination. For instance, we would expect low levels of an alpha-blocker, for whatever reason, to predispose to beta-blocker-induced bradycardia. On the flip-side low levels of a beta-blocker are expected to poorly oppose alpha-blocker-induced tachycardia with this combination. I would venture that pharmacogenetic-dependent kinetics may explain some of the variability observed in the effects of this combination in patients.