Pharmacological characteristics of the stereoisomers of carvedilol

Abstract
Summary The racemic compound carvedilol possesses two complementary pharmacological effects, vasodilation and β-blockade. TheR- andS-enantiomers of carvedilol and the racemate were investigated with respect to the β-blocking, vasodilating, and hypotensive actions. In agreement with results obtained with other β-blockers, only theS-enantiomer of carvedilol exerts β-blocking effects. In contrast, no substantial difference between the enantiomers could be seen with respect to α-blockade. The greater hypotensive activity ofS-carvedilol may be attributed to β-blockade, which inhibits counter-regulatory mechanisms provoked by vasodilation. From these results it is concluded that there is a rationale for using carvedilol as the racemate. Using theS-enantiomer would lead to relatively strong β-blockade with only a weak vasodilating effect. TheR-enantiomer alone would act only as a hypotensive agent without β-blockade.