Our library of drug research abstracts drawn from the medical literature is updated on a regular schedule, and you can be assured that new metoprolol research articles will be listed here shortly after becoming available to us.
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Medical research on metoprolol
Atrial Fibrillation due to Late Amiodarone-Induced Thyrotoxicosis.
Clin Drug Investig. 2008; 28(8): 527-531
Kurt IH, Yigit T, Karademir BM
A 60-year-old male patient complaining of palpitations, fatigue, weakness and weight loss of 1 month's duration was hospitalized in our cardiology department for atrial fibrillation. Thyroid function test results were compatible with thyrotoxicosis. The patient had been taking amiodarone for 2.5 years for hypertrophic obstructive cardiomyopathy and non-sustained ventricular tachycardia episodes. However, amiodarone had been discontinued after follow-up examinations revealed that the patient's ventricular arrhythmias were no longer present, and he had been taking metoprolol only for the preceding 6 months. In this patient, amiodarone-induced thyroiditis had developed 6 months after cessation of treatment, demonstrating that adverse effects may occur after discontinuation of amiodarone. Detection of the condition requires assessment of thyroid function before treatment initiation, during treatment and at regular intervals after treatment cessation. The type of hyperthyroidism induced by amiodarone cannot be determined in most cases. Patients with this condition should be referred to an experienced endocrinologist. Our case of delayed amiodarone-induced thryoiditis occcurred approximately 6 months after termination of amiodarone treatment.
Anaesthesist. 2008 Jul 4;
Petzoldt M, Kähler J, Goetz AE, Friederich P
Patients with major cardiac risk factors have been suggested to benefit from perioperative beta-blockade. However, the scientific literature on perioperative beta-blockade needs to be interpreted carefully. So far treatment recommendations for millions of patients are based on heterogeneous data from randomized trials with divergent study results. The evidence for a beneficial effect of perioperative beta-blockers is sufficient only for a limited subpopulation of high cardiac risk patients undergoing vascular surgery. Perioperative beta-blocker treatment is not useful in patients with intermediate risk and may even be harmful in patients with low cardiac risk. Therefore, an individualized risk-benefit analysis is an important prerequisite for a rational therapy that may be based on a standardized protocol including the Revised Cardiac Risk Index. Such a protocol is presented in this article. A recently reported trial (POISE) demonstrated that perioperative treatment with high doses of oral metoprolol efficiently reduces the incidence of cardiovascular events. However, due to severe adverse effects (hypotension, bradycardia, stroke) the total mortality was increased. Thus, dose adjustments, safety aspects, and monitoring of beta-blocker therapy seem to be mandatory. So far evidence from relevant trials about how to best implement perioperative beta-blockade is lacking. This article offers a simple clinical concept for this purpose.
Heart Surg Forum. 2008; 11(3): E159-63
Koçoğullari CU, Emmiler M, Ayva E, Sasirtan T, Eren N, Cekirdekci A
Background. We investigated the effects of preoperative administration of beta-blockers on the incidence of atrial fibrillation (AF) after cardiothoracic surgery and the resulting morbidity and mortality.Methods. We retrospectively evaluated 181 patients who underwent operations between May 2004 and December 2007. We divided the patients into 2 groups according to their preoperative use beta-blockers. Group A (n = 89) consisted of patients who did not receive beta-blockers, and group B (n = 92) consisted of patients who received 50 mg metoprolol succinate daily. All patients underwent on-pump coronary artery bypass grafting (CABG) via sternotomy.Results. Atrial sizes and the baseline clinical and laboratory data were similar for the 2 groups. The 2 groups were also similar with respect to the numbers of grafts per patient, preoperative ejection fractions, cross-clamp times, cardiopulmonary bypass times, and postoperative inotrope use (P > .05). AF occurred in 39 (21.5%) of the 181 patients after the operation. Postoperative AF occurred in 30 (33.7%) of the group A patients and in 9 patients (9.7%) in group B (P < .05).Conclusion. Postoperative AF increases the rates of morbidity and mortality and the length of hospital stay after CABG. The prophylactic use of beta-blockers decreases the rate of postoperative AF and thus AF-related complications.
Anesthesiology. 2008 Jul; 109(1): 72-80
Lange M, Smul TM, Redel A, Lotz C, Jazbutyte V, Schnupp V, Roewer N, Kehl F
BACKGROUND: Anesthetic preconditioning is mediated by beta- adrenergic signaling. This study tested the hypotheses that desflurane-induced preconditioning is dose-dependently blocked by metoprolol and mediated by calcium/calmodulin-dependent protein kinase II (CaMK II). METHODS: Pentobarbital-anesthetized New Zealand White rabbits were instrumented for measurement of systemic hemodynamics and subjected to 30 min of coronary artery occlusion followed by 3 h of reperfusion. Rabbits were assigned to receive vehicle (control), 0.2, 1.0, 1.75, or 2.5 mg/kg metoprolol for 30 min, or the CaMK II inhibitor KN-93 in the absence or presence of 1.0 minimum alveolar concentration desflurane. Protein expression of CaMK II, phospholamban, and phospho-phospholamban was measured by Western blotting. Myocardial infarct size and area at risk were measured with triphenyltetrazolium staining and patent blue, respectively. RESULTS: Baseline hemodynamics were not different among groups. Infarct size was 60 +/- 3% in control and significantly (* P < 0.05) decreased to 33 +/- 2%* by desflurane. The CaMK II inhibitor KN-93 did not affect infarct size (55 +/- 4%) but blocked desflurane-induced preconditioning (57 +/- 3%). Metoprolol at 0.2 and 1.0 mg/kg had no effect on infarct size (55 +/- 3% and 53 +/-3%), whereas metoprolol at 1.75 and 2.5 mg/kg reduced infarct size to 48 +/- 4%* and 39 +/- 5%*, respectively. Desflurane-induced preconditioning was attenuated by metoprolol at 0.2 mg/kg, leading to an infarct size of 46 +/- 5%*, and was completely abolished by metoprolol at 1.0, 1.75, and 2.5 mg/kg, resulting in infarct sizes of 51 +/- 3%, 52 +/- 3%, and 55 +/- 3%, respectively. CONCLUSIONS: Desflurane-induced preconditioning is dose-dependently blocked by metoprolol and mediated by CaMK II.
Int J Cardiol. 2008 Jun 23;
Braun M, Frank E, Markus K, Steffen S, Carsten S, Gregor S, Mathias B, Christof W, Ruth S
BACKGROUND: In addition to standard therapy with ACE-inhibitors, digitalis and diuretics, beta-adrenergic receptor blockers have become a widely accepted strategy in the treatment of chronic heart failure. The role of calcium antagonists in CHF however remains controversial. To evaluate if a combination therapy of metoprolol and felodipine might improve hemodynamic parameters, a randomized and placebo-controlled study was designed. METHODS AND RESULTS: Sixty-three patients with DCMP, LVEF 3 months in NYHA II-III on standard medication were prospectively treated with either a) a combination of metoprolol+felodipine (MF group, n=20), b) metoprolol+felodipine-placebo (MP group, n=23), or c) metoprolol-placebo+felodipine-placebo (PP group, n=20). Compared to baseline, LVEF and LVEDD significantly improved after 6 months in the MP group (LVEF: 36+/-2% vs 29+/-2%, p
Acta Neurochir (Wien). 2008 Jun 23;
Coenen VA, Gielen FL, Castro-Prado F, Abdel Rahman A, Honey CR
Background. Reversible changes in subthalamic nucleus (STN) activity, detected by microelectrode recording (MER), are reported in three patients who received an intravenous betablocker, metoprolol, during deep brain stimulation (DBS) for Parkinson's disease (PD). Methods. Metoprolol (MP) was given intravenously to reduce blood pressure during surgery. Systolic blood pressure dropped by 4, 11 and 17%, indicating a systemic beta - adrenoceptor blocking effect. Findings. In all patients, the bursting spiking activity of the STN was temporarily suppressed, after the application of MP. Unexpectedly, a transient reduction in Parkinson symptoms (rigidity) was recorded during suppression of STN spiking activity in patient 2. Conclusion. The reversible suppression of STN activity and Parkinson symptoms with the beta1-selective adrenoceptor antagonist MP has not been reported. It supports the theory, that - as recently reported in the rat - the human STN is influenced by adrenergic inputs. This report supports the possible application of adrenergic antagonist drugs for the use in Parkinson's disease and advocates additional neurophysiological and pharmacological research in this field.
Cardiogenic shock following nasal septoplasty: a case report and review of the literature.
Can J Anaesth. 2008 Jun; 55(6): 376-9
Schwalm JD, Hamstra J, Mulji A, Velianou JL
PURPOSE: Nasal septoplasty is a surgical procedure offered to patients with chronic snoring secondary to nasal obstruction. We describe a case of cardiogenic shock following the administration of metoprolol to treat hypertension, (likely) induced by systemic absorption of topical epinephrine used during a routine nasal septoplasty. CLINICAL FEATURES: A 29-yr-old male, with no significant medical history, was scheduled for nasal septoplasty for mild nasal obstruction. Following routine anesthetic induction, cotton balls, soaked with epinephrine (1:1000), were applied to the nasal mucosa. The patient became hypertensive with a blood pressure of 207/123 mmHg. Intravenous metoprolol was administered. Severe pulmonary edema ensued, with resulting hypoxic respiratory failure and cardiogenic shock. The patient was transferred to a tertiary care facility for percutaneous cardiopulmonary bypass. After five days of cardiopulmonary bypass support and six weeks of intensive care monitoring, the patient's cardiac status returned to normal limits. CONCLUSION: A hypertensive response, following systemically absorbed topical vasoconstrictors, including both phenylephrine and epinephrine, can be associated with dire consequences when treated with a beta-adrenergic blocking drug and, possibly, calcium channel blockers. To prevent severe complications including; pulmonary edema, cardiogenic shock, cardiac arrest, and, possibly, death, these drug interactions need to be appreciated.
Diabetes Obes Metab. 2008 Jun 17;
Bell DS, Bakris GL, McGill JB
Context: Vasoconstricting beta-blocker use is associated with a reduction in HDL cholesterol, higher triglyceride, total cholesterol and LDL cholesterol levels, whereas carvedilol, a vasodilating beta-blocker, has not been associated with these effects. Objective: To compare in a randomized, double-blind study, the effects of the beta 1-blocker metoprolol tartrate with the combined alpha 1, beta-blocker carvedilol on serum lipid concentrations. Methods: A prospective randomized, double-blind, parallel-group trial compared the effects of carvedilol and metoprolol on total cholesterol, triglycerides, calculated LDL, HDL and non-HDL cholesterol levels at baseline and after 5 months of therapy as a secondary objective in the Glycemic Effects in Diabetes Mellitus: Carvedilol-Metoprolol Comparison in Hypertensive (GEMINI) study. In this study, 1235 participants with type 2 diabetes and hypertension who were receiving renin-angiotensin system blockers were randomized either to carvedilol, receiving 6.25-25 mg twice daily, or to metoprolol tartrate, receiving 50-200 mg twice daily. If needed, hydrochlorothiazide and a dihydropyridine calcium channel blocker were added to achieve blood pressure goals. Results: In the metoprolol tartrate group, triglycerides and non-HDL cholesterol increased and both the LDL and the HDL cholesterol levels decreased. In the carvedilol group, total LDL and HDL cholesterol decreased, non-HDL cholesterol was unchanged and triglycerides increased. Comparing the carvedilol and metoprolol tartrate groups, there was no statistically significant difference in LDL and HDL cholesterol levels, but there was a significantly greater decreases with carvedilol in total cholesterol [-2.9%, 95% confidence interval (CI) -4.60 to -1.15, p < 0.001], triglycerides (-9.8%, 95% CI -13.7, -5.75%, p < 0.001) and non-HDL cholesterol (-4.03%, 95% CI -6.3 to -1.8, p < 0.0006). At the end of the study, significantly more participants in the metoprolol tartrate group had had initiation of statin therapy or the statin dose increased than those in the carvedilol group (11 vs. 32%, p = 0.04). Conclusions: In patients with type 2 diabetes currently receiving a renin-angiotensin blocker, compared with metoprolol tartrate, the addition of carvedilol for blood pressure control resulted in a significant decrease in triglyceride, total cholesterol and non-HDL cholesterol levels. The use of metoprolol resulted in a significantly greater rate of initiation of statin therapy or an increase in the dose of existing statin therapy when compared with carvedilol utilization.
Eur J Clin Pharmacol. 2008 Jun 11;
Seeringer A, Brockmöller J, Bauer S, Kirchheiner J
OBJECTIVE: Our objective was to study the enantioselective pharmacokinetics of metoprolol in CYP2D6 ultra-rapid metabolizers (UM) compared with extensive (EM) and poor (PM) metabolizers to quantify differential effects of metoprolol enantiomers on the beta1-adrenoreceptor blockade. METHODS: Twenty-nine healthy individuals were selected based on their CYP2D6 genotype, and 100 mg racemic metoprolol was administered. Plasma concentrations of R- and S-metoprolol and the metabolites SS-, SR-, RS-, and RR-hydroxymetoprolol were quantified by high-performance liquid chromatography. RESULTS: Mean (+/-SD) AUCs of S-metoprolol were 190 +/- 99 ng/ml.h in UMs, 366 +/- 158 in EMs, and 1,804 +/- 300 in PMs. For R-metoprolol, the AUCs were 127 +/- 72 ng/ml.h in UMs, 261 +/- 126 in EMs, and 1,746 +/- 319 in PMs. The concentrations of R-metoprolol and S-metoprolol, respectively, needed to obtain a half-maximum reduction in heart rate were estimated as 20 and 21 ng/ml in PMs, 11 and 17 ng/ml in EMs, and 7 and 11 ng/ml in UMs. CONCLUSION: A slight enantiopreference towards metabolism of R-metoprolol by CYP2D6 was observed in EMs and even more in the UM group, but the effect was far from being enantioselective.
The development of multiple probe microdialysis sampling in the stomach.
J Pharm Biomed Anal. 2008 Apr 26;
Woo KL, Lunte CE
A multiple probe approach of implanting microdialysis probes into each separate tissue layer would better represent sampling from the stomach. Presently, microdialysis sampling experiments are performed with only a single probe in the submucosa to represent sampling from the stomach tissue. The focus of this research was to develop a four-probe microdialysis sampling design to simultaneously monitor the stomach lumen, mucosa, submucosa and in the blood of the rat. Due to the small outer diameter of the microdialysis probe (350mum), implantation into each separate layer was achieved with confirmation of probe location from histological examination. To assess the significance of sampling by this approach, multiple probe microdialysis sampling was used to monitor drug absorption in the stomach. Salicylic acid, caffeine and metoprolol were individually dosed to the ligated stomach. Analysis of the dialysate samples was performed by HPLC-UV and concentration-time curves and pharmacokinetics analysis were used to determine differences between the different probe locations.