Metoprolol succinate, a selective beta-adrenergic blocker, has no effect on insulin sensitivity

Vascular Effects of Avocado Seed Glycosides during Diabetes-induced Endothelial Damage

BACKGROUND AND OBJECTIVES

The relationship between vascular damage and diabetes mellitus was exploited using avocado seed extracts. The purpose of the study was to understand the therapeutic relevance of glycosides compared to standard vascular and anti-diabetic drugs. Constituent Avocado Seed Glycosides (ASG) were analysed and administered to rats with Diabetes-Induced Vascular Damage (DIVD).

METHODS

The rats were first administered with streptozotocin and screened after seven days for alterations in blood glucose, insulin, vascular cell adhesion molecule (VCAM-1), Von Willebrand factor (VWF), Renin-Angiotensin-Aldosterone System (RAS), eNOx, and endothelin-1 (ET-1). Only rats that satisfied these criteria were recruited and treated with either glibenclamide, met.su + losart, or 200 mg/kg body weight ASG for 28 days.

RESULTS

There was an abundance of digitoxin (13.41 mg/100g), digoxin (17.98 mg/100g), avicularin (165.85 mg/100g), and hyperoside (282.51 mg/100g). ASG or met.su + losart exhibited slight modulatory properties on glucose homeostasis. Rats with DIVD showed elevated renin, angiotensin, VCAM-1 and Lp-PLA2 levels but slightly decreased with glibenclamide treatment and normalized with ASG or met.su + losart administration. All treatments normalized Hcy levels. DIVD caused the overproduction of CnT, LDH, Crt-K, LDL-c, TG, and TC and suppressed HDL-c but was completely normalized by the ASG. Water intake remained altered in treated rats.

CONCLUSION

The ASG had no relevant effect on glucose homeostasis during DIVD but showed significant vasoprotective properties.

Measurements, Thermodynamic Modeling, and a Hydrogen Bonding Study on the Solubilities of Metoprolol Succinate in Organic Solvents

The solubilities of metoprolol succinate (a cardioselective β1 adrenergic receptor) in methanol, ethanol, n-propanol, isopropanol, n-butanol, ethyl acetate, and acetone were measured at temperatures ranging from (278.2 to 318.2) K using a solid–liquid equilibrium method. The solubility of metoprolol succinate increases with increasing temperature. At a fixed temperature, the solubility decreases in the order methanol > ethanol > n-butanol > n-propanol > isopropanol > acetone > ethyl acetate. The enthalpy of fusion and the melting point of metoprolol succinate were determined by differential scanning calorimetry. The thermodynamic properties of the dissolution process, determined by a van’t Hoff analysis, have been obtained and are discussed. The modified Apelblat equation, Wilson model, and non-random two-liquid (NRTL) model were employed to correlate the solubilities of metoprolol succinate in different solvents. Finally, a quantitative structure–property relationship (QSPR) study of physical properties of solvents and density functional theory simulations of hydrogen-bonding structure were carried out to give the explanation for the sequence of solubility in alcohols. The density functional theory (DFT) calculations well illustrated that the solubility of metoprolol succinate in various alcohols can be mainly attributed to the intra- and intermolecular hydrogen bonds in metoprolol succinate-solvent complexes.

Metoprolol in the treatment of cardiovascular disease: a critical reappraisal

BACKGROUND

Extensive clinical experience on metoprolol has been gained in different cardiovascular conditions.

REVIEW

This paper discusses the use of metoprolol, with a focus on the extended-release formulation, in clinical practice in the light of existing evidence and current recommendations. This is a narrative review based on existing evidence and clinical experience of the author. Evidence on the use of metoprolol in heart failure, ischemic artery disease, arterial hypertension, and atrial fibrillation is well-established.

CONCLUSIONS

Metoprolol still appears to be a suitable pharmacological option in different cardiovascular conditions. Research on this molecule is still active and new, promising settings of use are being explored and may provide relevant results in the years to come.

Primary hypertension is a disease of premature vascular aging associated with neuro-immuno-metabolic abnormalities

There is an increasing amount of data indicating that primary hypertension (PH) is not only a hemodynamic phenomenon but also a complex syndrome involving abnormal fat tissue distribution, over-activity of the sympathetic nervous system (SNS), metabolic abnormalities, and activation of the immune system. In children, PH usually presents with a typical phenotype of disturbed body composition, accelerated biological maturity, and subtle immunological and metabolic abnormalities. This stage of the disease is potentially reversible. However, long-lasting over-activity of the SNS and immuno-metabolic alterations usually lead to an irreversible stage of cardiovascular disease. We describe an intermediate phenotype of children with PH, showing that PH is associated with accelerated development, i.e., early premature aging of the immune, metabolic, and vascular systems. The associations and determinants of hypertensive organ damage, the principles of treatment, and the possibility of rejuvenation of the cardiovascular system are discussed.

Beta-blocker use for the stages of heart failure

The 2005 American Heart Association/American College of Cardiology heart failure (HF) guidelines contributed to a renewed focus on "at-risk" patients and emphasized HF as a progressive disease. Patient categorization by stages focused attention on customization of therapy to achieve optimal, evidence-based treatments across the HF continuum. Therapy for risk factors that predispose patients to left ventricular dysfunction or other symptoms may help reduce HF development. beta-Blockers are valuable for treatment of HF; however, the class is heterogeneous, and proper beta-blocker selection for each HF stage is important. beta-Blockers have been used routinely to treat patients with stage A HF with hypertension. Recent controversy regarding the detrimental effects that some beta-blockers have on metabolic parameters has raised inappropriate concerns about the use of any beta-blocker for diabetes. beta-Blockade is standard therapy for the patient with stage B HF who has had a myocardial infarction, but few data are available concerning use in asymptomatic patients with left ventricular dysfunction. Additionally, beta-blockers are part of the core therapy for stage C HF and selected patients with stage D HF. This review examines the role and use of beta-blockers in each HF stage through an evidence-based approach to provide better understanding of their importance in this progressive disease. PubMed searches (1980-2008) identified large clinical trials that evaluated cardiovascular events and outcomes in any HF stage or hypertension. Search terms were heart failure, hypertension, beta-blocker, ACEI, ARB, and calcium channel blocker AND blood pressure coronary artery disease, diabetes, efficacy, left ventricular dysfunction, metabolism, mortality, myocardial infarction, or stroke.

Metoprolol succinate combination in the treatment of hypertension

Metoprolol is a selective beta(1)-adrenergic antagonist extensively used since 1975. Metoprolol has proven its efficacy in reducing cardiovascular events and mortality in patients with hypertension and coronary heart disease. A recently developed controlled release/ extended-release formulation of metoprolol succinate was designed to provide relatively constant metoprolol plasma concentrations and beta(1)-blockade while retaining the convenience of once daily administration. A 100-mg metoprolol controlled/extended-release tablet contains 95 mg of metoprolol succinate and is considered to have equivalent activity of 100 mg metoprolol tartrate. After ingestion, the tablet disintegrates into individual pellets and each pellet acts as a diffusion cell releasing the drug at a relatively constant rate over a period of approximately 20 hours. The aim of this review was to determine the pharmacokinetic and pharmacodynamic properties of metoprolol succinate and to apply those properties in combination with other drugs mainly diuretics in the treatment of hypertension.

Treatment with metoprolol succinate, a selective beta adrenergic blocker, lowers blood pressure without altering insulin sensitivity in diabetic patients

Insulin resistance is a risk factor for cardiovascular disease. Therapies to lower blood pressure should not decrease insulin sensitivity, especially among high-risk patients such as diabetics. This study examined the effect of the beta1-selective adrenergic receptor-blocking agent extended-release metoprolol succinate (ER metoprolol) on insulin sensitivity in type 2 diabetic patients with suboptimal blood pressure control. Diabetic patients with average blood pressure levels >130/85 mm Hg despite antihypertensive therapy had insulin sensitivity quantified by insulin clamp. ER metoprolol was then added to their ongoing therapy. Following 12 weeks of ER metoprolol plus other therapy, the insulin clamp study was repeated. There were no significant changes in measures of insulin sensitivity, plasma lipids, or hemoglobin A1c with use of ER metoprolol. When beta-blocker therapy is considered, it appears that this agent can be used to treat hypertension without adverse effects on insulin sensitivity in patients with type 2 diabetes, at least over the period of time treated.

Metoprolol succinate extended release/hydrochlorothiazide combination tablets

Lowering elevated blood pressure (BP) with drug therapy reduces the risk for catastrophic fatal and nonfatal cardiovascular events such as stroke and myocardial infarction. Given the heterogeneity of hypertension as a disease, the marked variability in an individual patient's BP response, and low response rates with monotherapy, expert groups such as the Joint National Committee (JNC) emphasize the value of combination antihypertensive regimens, noting that combinations, usually of different classes, have additive antihypertensive effects. Metoprolol succinate extended-release tablet is a beta-1 (cardio-selective) adrenoceptor-blocking agent formulated to provide controlled and predictable release of metoprolol. Hydrochlorothiazide (HCT) is a well-established diuretic and antihypertensive agent, which promotes natruresis by acting on the distal renal tubule. The pharmacokinetics, efficacy, and safety/tolerability of the antihypertensive combination tablet, metoprolol extended release hydrochlorothiazide, essentially reflect the well-described independent characteristics of each of the component agents. Not only is the combination product more effective than monotherapy with the individual components but the combination product allows a low-dose multidrug regimen as an alternative to high-dose monotherapy, thereby, minimizing the likelihood of dose-related side-effects.