Antioxidant properties of carvedilol and metoprolol in heart failure: A double-blind randomized controlled trial

Animal and human studies have shown that carvedilol has significant antioxi dant properties compared with other beta -blockers. The objective of this s tudy was to determine if these antioxidant effects: are detectable in patie nts with heart failure and to compare carvedilol with the selective beta -b locker metoprolol. Twenty-four patients with chronic heart failure were ran domly assigned to receive either carvedilol or metoprolol in a double-blind control trial for 12 weeks in a University teaching hospital clinic. Blood pressure, heart rate, exercise tolerance, left ventricular ejection fracti on, plasma total antioxidant status, erythrocyte superoxide dismutase, and glutathione peroxidase activities were determined at baseline and every 4 w eeks up to 12 weeks. The results showed that erythrocyte superoxide dismuta se and glutathione peroxidase were significantly reduced in carvedilol trea ted patients after 12 weeks of therapy, whereas metoprolol had no significa nt effect, although the clinical improvement over the short-term was simila r with both drugs. Thus carvedilol, in addition to improving symptoms in he art failure, also possesses significant antioxidant properties. Whether thi s additional action influences long-term outcome is at present unknown.