1.
The effect of nebivolol treatment on oxidative stress and antioxidant status in patients with cardiac syndrome-X.
Erdamar, H, Sen, N, Tavil, Y, Yazici, HU, Turfan, M, Poyraz, F, Topal, S, Okuyan, H, Cemri, M, Cengel, A
Coronary artery disease. 2009;(3):238-4
Abstract
BACKGROUND Free radical-mediated oxidative stress has been implicated in the etiopathogenesis of several disorders. The aim of this study was to elucidate the effect of treatment with nebivolol on the metabolic state of oxidative stress, and antioxidant status markers in patients with cardiac syndrome-X (CSX), additionally, to compare with the effect of metoprolol treatment. METHODS Thirty patients, 17 female and 13 male, with CSX were enrolled in the study. Nebivolol (5 mg/day) or metoprolol (50 mg/day) was administrated for 12 weeks. Twelve hour fasting blood samples, taken at the initiation and on the third month of therapy, were analyzed for the levels of malondialdehyde (MDA), nitrite+nitrate (NOx), and the activity of myeloperoxidase (MPO), superoxide dismutase (SOD). No patient presented additional risk factors for increased reactive oxygen species levels. RESULTS Compared with sixteen control participants, patients with CSX had significantly higher activity of MPO and levels of MDA, but significantly lower SOD activity and levels of NOx before treatment. After treatment, MPO activity and MDA levels were significantly reduced; SOD activity and NOx levels were significantly increased with nebivolol but remained unchanged with metoprolol. CONCLUSION We have shown that patients with CSX who taken nebivolol have lower serum MPO activity, levels of MDA and higher serum SOD activity, NOx levels when compared with metoprolol treatment. Exercise stress test parameters were also ameliorated in patients who had taken nebivolol in contrast to metoprolol. Nebivolol treatment may be a novel treatment strategy in cases with CSX in the future.
2.
Metabolic effects of carvedilol vs metoprolol in patients with type 2 diabetes mellitus and hypertension: a randomized controlled trial.
Bakris, GL, Fonseca, V, Katholi, RE, McGill, JB, Messerli, FH, Phillips, RA, Raskin, P, Wright, JT, Oakes, R, Lukas, MA, et al
JAMA. 2004;(18):2227-36
Abstract
CONTEXT Beta-blockers have been shown to decrease cardiovascular risk in patients with hypertension and type 2 diabetes mellitus (DM); however, some components of the metabolic syndrome are worsened by some beta-blockers. OBJECTIVE To compare the effects of beta-blockers with different pharmacological profiles on glycemic and metabolic control in participants with DM and hypertension receiving renin-angiotensin system (RAS) blockade, in the context of cardiovascular risk factors. DESIGN, SETTING, AND PARTICIPANTS A randomized, double-blind, parallel-group trial (The Glycemic Effects in Diabetes Mellitus: Carvedilol-Metoprolol Comparison in Hypertensives [GEMINI]) conducted between June 1, 2001, and April 6, 2004, at 205 US sites that compared the effects of carvedilol and metoprolol tartrate on glycemic control. The 1235 participants were aged 36 to 85 years with hypertension (>130/80 mm Hg) and type 2 DM (glycosylated hemoglobin [HbA1c], 6.5%-8.5%) and were receiving RAS blockers. Participants were followed up for 35 weeks. INTERVENTIONS Participants were randomized to receive a 6.25- to 25-mg dose of carvedilol (n = 498) or 50- to 200-mg dose of metoprolol tartrate (n = 737), each twice daily. Open-label hydrochlorothiazide and a dihydropyridine calcium antagonist were added, if needed, to achieve blood pressure target. MAIN OUTCOME MEASURES Difference between groups in mean change from baseline HbA1c following 5 months of maintenance therapy. Additional prespecified comparisons included change from baseline HbA1c in individual treatment groups, treatment effect on insulin sensitivity, and microalbuminuria. RESULTS The 2 groups differed in mean change in HbA1c from baseline (0.13%; 95% confidence interval [CI], -0.22% to -0.04%; P = .004; modified intention-to-treat analysis). The mean (SD) HbA1c increased with metoprolol (0.15% [0.04%]; P<.001) but not carvedilol (0.02% [0.04%]; P = .65). Insulin sensitivity improved with carvedilol (-9.1%; P = .004) but not metoprolol (-2.0%; P = .48); the between-group difference was -7.2% (95% CI, -13.8% to -0.2%; P = .004). Blood pressure was similar between groups. Progression to microalbuminuria was less frequent with carvedilol than with metoprolol (6.4% vs 10.3%; odds ratio, 0.60; 95% CI, 0.36-0.97; P = .04). CONCLUSIONS Both beta-blockers were well tolerated; use of carvedilol in the presence of RAS blockade did not affect glycemic control and improved some components of the metabolic syndrome relative to metoprolol in participants with DM and hypertension. The effects of the 2 beta-blockers on clinical outcomes need to be compared in long-term clinical trials.