Mechanism action of Carvedilol
Carvedilol is a racemic mixture in which nonselective
beta-adrenoreceptor blocking activity is present in the S(-) enantiomer
and alpha-adrenergic blocking activity is present in both R(+) and S(-)
enantiomers at equal potency. Carvedilol's beta-adrenergic receptor
blocking ability decreases the heart rate, myocardial contractility, and
myocardial oxygen demand. Carvedilol also decreases systemic vascular
resistance via its alpha adrenergic receptor blocking properties.
Carvedilol and its metabolite BM-910228 (a less potent beta blocker, but
more potent antioxidant) have been shown to restore the inotropic
responsiveness to Ca2+ in OH- free radical-treated myocardium. Carvedilol and its metabolites also prevent OH- radical-induced decrease in sarcoplasmic reticulum Ca2+-ATPase
activity. Therefore, carvedilol and its metabolites may be beneficial
in chronic heart failure by preventing free radical damage.
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