Serious Bleeding in Patients With Atrial Fibrillation Using Diltiazem With Apixaban or Rivaroxaban.

Importance: Diltiazem, a commonly prescribed ventricular rate-control medication for patients with atrial fibrillation, inhibits apixaban and rivaroxaban elimination, possibly causing overanticoagulation. Objective: To compare serious bleeding risk for new users of apixaban or rivaroxaban with atrial fibrillation treated with diltiazem or metoprolol. Design, Setting, and Participants: This retrospective cohort study included Medicare beneficiaries aged 65 years or older with atrial fibrillation who initiated apixaban or rivaroxaban use and also began treatment with diltiazem or metoprolol between January 1, 2012, and November 29, 2020. Patients were followed up to 365 days through November 30, 2020. Data were analyzed from August 2023 to February 2024. Exposures: Diltiazem and metoprolol. Main Outcomes and Measures: The primary outcome was a composite of bleeding-related hospitalization and death with recent evidence of bleeding. Secondary outcomes were ischemic stroke or systemic embolism, major ischemic or hemorrhagic events (ischemic stroke, systemic embolism, intracranial or fatal extracranial bleeding, or death with recent evidence of bleeding), and death without recent evidence of bleeding. Hazard ratios (HRs) and rate differences (RDs) were adjusted for covariate differences with overlap weighting. Results: The study included 204 155 US Medicare beneficiaries, of whom 53 275 received diltiazem and 150 880 received metoprolol. Study patients (mean [SD] age, 76.9 [7.0] years; 52.7% female) had 90 927 person-years (PY) of follow-up (median, 120 [IQR, 59-281] days). Patients receiving diltiazem treatment had increased risk for the primary outcome (RD, 10.6 [95% CI, 7.0-14.2] per 1000 PY; HR, 1.21 [95% CI, 1.13-1.29]) and its components of bleeding-related hospitalization (RD, 8.2 [95% CI, 5.1-11.4] per 1000 PY; HR, 1.22 [95% CI, 1.13-1.31]) and death with recent evidence of bleeding (RD, 2.4 [95% CI, 0.6-4.2] per 1000 PY; HR, 1.19 [95% CI, 1.05-1.34]) compared with patients receiving metoprolol. Risk for the primary outcome with initial diltiazem doses exceeding 120 mg/d (RD, 15.1 [95% CI, 10.2-20.1] per 1000 PY; HR, 1.29 [95% CI, 1.19-1.39]) was greater than that for lower doses (RD, 6.7 [95% CI, 2.0-11.4] per 1000 PY; HR, 1.13 [95% CI, 1.04-1.24]). For doses exceeding 120 mg/d, the risk of major ischemic or hemorrhagic events was increased (HR, 1.14 [95% CI, 1.02-1.27]). Neither dose group had significant changes in the risk for ischemic stroke or systemic embolism or death without recent evidence of bleeding. When patients receiving high- and low-dose diltiazem treatment were directly compared, the HR for the primary outcome was 1.14 (95% CI, 1.02-1.26). Conclusions and Relevance: In Medicare patients with atrial fibrillation receiving apixaban or rivaroxaban, diltiazem was associated with greater risk of serious bleeding than metoprolol, particularly for diltiazem doses exceeding 120 mg/d.

Prospective Clinical Trial Comparing IV Esmolol to IV Metoprolol in CT Coronary Angiography: Effect on Hemodynamic, Technical Parameters and Cost.

BACKGROUND: Intravenous [IV] esmolol, an alternative to IV metoprolol for coronary computed tomography angiography [CCTA], has shorter half-life that decreases the risk of prolonged hypotension. The primary aim was to prospectively compare IV esmolol alone to IV metoprolol alone for effectiveness in achieving heart rate [HR] of 60 beats per minute[bpm] during CCTA. The secondary aim was to compare hemodynamic response, image quality, radiation dose and cost. MATERIALS AND METHODS: Institutional Review Board approved prospective randomized study of 28 CCTA patients medicated in a 1:1 blinded match with IV esmolol or IV metoprolol to achieve HR of 60 bpm. Serial hemodynamic response was measured at 6 specified times. Two cardiac radiologists independently scored the image quality. RESULTS: Both IV esmolol and IV metoprolol achieved the target HR. IV esmolol resulted in significantly less profound and shorter duration of reduction in systolic blood pressure [BP] than IV metoprolol with a difference of -10, -14 and -9 mm Hg compared to -20, -26 and -25 mmHg at 2, 15 & 30 min respectively. No significant difference in HR at image acquisition, exposure window, radiation dose and image quality. Although IV esmolol was expensive, the overall cost of care was comparable to IV metoprolol due to shortened post CCTA observation period consequent to faster restoration of hemodynamic status. CONCLUSION: Comparison of IV esmolol and IV metoprolol demonstrate that both are effective in achieving the target HR but significantly faster recovery of HR and BP in patients who receive IV esmolol was found.

Assessment of effects of repeated oral doses of fedratinib on inhibition of cytochrome P450 activities in patients with solid tumors using a cocktail approach.

PURPOSE: Fedratinib, an oral selective kinase inhibitor with activity against both wild type and mutationally activated Janus kinase 2, has been approved for the treatment of adult patients with intermediate-2 or high-risk myelofibrosis by the US Food and Drug Administration. In vitro studies indicated that fedratinib was an inhibitor of several cytochrome P450 (CYP) enzymes. The primary objective of this study was to evaluate the effects of repeated doses of fedratinib on the activity of CYP2D6, CYP2C19, and CYP3A4 in patients with solid tumors using a CYP probe cocktail. METHODS: An open-label, one-sequence, two-period, two-treatment crossover study was conducted. Patients were administered a single oral dose cocktail of metoprolol (100 mg), omeprazole (20 mg), and midazolam (2 mg) used as probe substrates for CYP2D6, CYP2C19, and CYP3A4 enzyme activities, respectively, without fedratinib on Day -1 or with fedratinib on Day 15. RESULTS: Coadministration of 500 mg once-daily doses of fedratinib for 15 days increased the mean area under the plasma concentration-time curve from time zero to infinity following a single-dose cocktail containing metoprolol (CYP2D6 substrate), omeprazole (CYP2C19 substrate), and midazolam (CYP3A4 substrate) by 1.77-fold (90% confidence interval [CI] 1.27-2.47) for metoprolol, 2.82-fold (90% CI 2.26-3.53) for omeprazole, and 3.84-fold (90% CI 2.62-5.63) for midazolam, respectively. The mean plasma Day 14/Day 1 ratio of 4ß-hydroxycholesterol, an endogenous biomarker of CYP3A4 activity, was 0.59 (90% CI 0.54-0.66), suggesting a net inhibition of CYP3A4 by fedratinib. CONCLUSION: Fedratinib is a weak inhibitor of CYP2D6, and a moderate inhibitor of CYP2C19 and CYP3A4. These results serve as the basis for dose modifications of these CYP substrate drugs when co-administered with fedratinib.

Blood pressure response to metoprolol and chlorthalidone in European and African Americans with hypertension.

Despite the availability of many antihypertensive drug classes, half of patients with hypertension have uncontrolled blood pressure (BP). The authors sought to assess the effect of age on BP response in European American and African American patients with hypertension. Clinic BP from the PEAR2 (Pharmacogenomics Evaluation of Antihypertensive Responses 2) study was used to estimate BP responses from baseline following sequential treatment with metoprolol 100 mg twice daily and chlorthalidone 25 mg daily for 8 to 9 weeks each, with a minimum 4-week washout between treatments. BP responses to both drugs were compared in 159 European Americans and 119 African Americans by age with adjustment for baseline BP and sex. European Americans younger than 50 years responded better to metoprolol than chlorthalidone (diastolic BP: -9.6 ± 8.0 vs -5.9 ± 6.8 mm Hg, adjusted P = .003), whereas patients 50 years and older responded better to chlorthalidone than metoprolol (systolic BP: -18.7 ± 13.8 vs -13.6 ± 14.8 mm Hg, adjusted P = .008). African Americans younger than 50 years responded similarly to both drugs, whereas those 50 years and older responded better to chlorthalidone than metoprolol (-17.0 ± 13.2/-9.6 ± 7.5 vs -7.0 ± 18.6/-6.7 ± 9.3 mm Hg, adjusted P<.0001/.008). Therefore, age should be considered when selecting antihypertensive therapy in European and African American populations with hypertension.

Rationale for the Assessment of Metoprolol in the Prevention of Vasovagal Syncope in Aging Subjects Trial (POST5).

BACKGROUND: Vasovagal syncope (VVS) is a common problem associated with a poor quality of life, which improves when syncope frequency is reduced. Effective pharmacological therapies for VVS are lacking. Metoprolol is a ß-adrenergic receptor antagonist that is ineffective in younger patients, but may benefit older (≥40 years) VVS patients. Given the limited therapeutic options, a placebo-controlled clinical trial of metoprolol for the prevention of VVS in older patients is needed. STRUCTURE OF STUDY: The POST5 is a multicenter, international, randomized, placebo-controlled study of metoprolol in the prevention of VVS in patients ≥40 years old. The primary endpoint is the time to first recurrence of syncope. Patients will be randomized 1:1 to receive metoprolol 25 to 100 mg BID or matching placebo, and followed up for 1 year. Secondary end points include syncope frequency, presyncope, quality of life, and cost analysis. Primary analysis will be intention to treat, with a secondary on-treatment analysis. POWER CALCULATIONS: A sample size of 222, split equally between the groups achieves 85% power to detect a hazard rate of 0.3561 when the event rates are 50% and 30% in the placebo and metoprolol arms. Allowing for 10% dropout, we propose to enroll 248 patients. IMPLICATIONS: This study will be the first adequately powered trial to determine whether metoprolol is effective in preventing VVS in patients ≥40 years. If effective, metoprolol may become the first line pharmacological therapy for these patients.

Is the Preoperative Administration of Amiodarone or Metoprolol More Effective in Reducing Atrial Fibrillation: After Coronary Bypass Surgery?

This study examined the influence of preoperative administration of amiodarone and metoprolol in preventing postoperative atrial fibrillation (AF) after coronary artery bypass grafting (CABG) surgery.The study comprised 251 patients who underwent CABG surgery at our hospital between January 2012 and May 2014. The patients were randomly divided into 2 groups: amiodarone therapy group (n = 122 patients) and metoprolol therapy group (n = 129 patients).In the amiodarone group, the patients received amiodarone tablet orally 1 week before coronary bypass surgery and during the postoperative period. In the metoprolol group, the patients received metoprolol tablet orally 1 week before surgery and during the postoperative period. The AF development rate was retrospectively evaluated between the first 3 days and 4 weeks after surgery.AF developed in 14 patients in the amiodarone group and 16 patients in the metoprolol group 4 weeks after the operation (P = 0.612).No significant difference was observed between the groups in terms of intensive care unit and hospital stay. Furthermore, hospital charges were similar in both groups (P = 0.741).The results of the logistic regression analysis showed age, left ventricular ejection fraction, left atrial diameter, and aortic cross-clamping time to be predictors for postoperative AF.This study demonstrates that amiodarone and metoprolol have similar effects in prevention of AF after cardiac surgery. However, larger-scale studies need to be conducted to substantiate these findings.

Efectividad y seguridad del metoprolol succinato en pacientes con taquiarritmias supraventriculares / Effectiveness and safety of metoprolol succinate in patients with supraventricular tachyarrhythmias

Introducción: Se define como arritmia cardiaca a cualquier ritmo diferente al sinusal en presencia de un sistema de conducción atrioventricular normal y como taquiarritmia, a los ritmos cardiacos anormales con frecuencia ventricular mayor a 100 por minuto. Las taquiarritmias supraventriculares (TSV) son aquellas cuyo sitio de formación del impulso se origina por encima de la bifurcación del haz de His; pueden ser repetitivas, persistentes y algunas veces poner en riesgo la vida. Objetivo: Evaluar la evidencia científica sobre los beneficios y riesgos del uso de metoprolol succinato en el tratamiento de pacientes con TSV como uno de los criterios para informar la toma de decisiones relacionada con la posible inclusión de tecnologías en el Plan Obligatorio de Salud, en el marco de su actualización ordinaria para el año 2015. Metodología: Se buscaron revisiones sistemáticas y estudios primarios en los que se hubiera evaluado el uso de metoprolol succinato para evitar episodios de una TSV o para controlar la frecuencia ventricular en el caso de la fibrilación y el flutter auricular. El comparador podía ser placebo, cualquier otro betabloqueador (incluso el metoprolol tartrato) o calcioantagonistas no dihidropiridínicos (verapamilo o diltiazem). No se restringió por fecha de publicación y se buscaron estudios en inglés o español. Resultados: No se encontraron revisiones sistemáticas ni estudios primarios de buena calidad diseñados específicamente para evaluar el impacto del metoprolol succinato sobre los desenlaces clínicamente importantes en pacientes con TSV. Evidencia de baja calidad demostró que en pacientes con FA y falla cardiaca sistólica el uso de metoprolol succinato no disminuye la mortalidad ni las hospitalizaciones y tampoco mejora la calidad de vida. En pacientes con falla cardiaca sistólica en ritmo sinusal, el uso del medicamento succinato se asoció con una disminución en la incidencia de FA. Evidencia de moderada calidad demostró que en pacientes con FA persistente el uso de metoprolol succinato retrasa el tiempo hasta la recaída después de una cardioversión exitosa. Evidencia de muy baja calidad demostró que en pacientes con taquicardia sinusal inapropiada el metoprolol succinato es tan efectivo como la ivabradina para disminuir la frecuencia cardiaca en reposo. Conclusiones: Se necesitan estudios de buena calidad metodológica diseñados específicamente para evaluar la efectividad del metoprolol succinato sobre desenlaces clínicamente importantes en pacientes con TSV.(AU)

Cost-effectiveness analysis of nebivolol and metoprolol in essential hypertension: a pharmacoeconomic comparison of antihypertensive efficacy of beta blockers.

OBJECTIVE: To estimate and compare the cost-effectiveness and safety of nebivolol with sustained-release metoprolol in reducing blood pressure by 1 mm of Hg per day in hypertensive patients. MATERIALS AND METHODS: This was a prospective, randomized, open label, observational analysis of cost-effectiveness, in a questionnaire-based fashion to compare the cost of nebivolol (2.5 mg, 5 mg, 10 mg) and sustained released metoprolol succinate (25 mg, 50 mg, 100 mg) in hypertensive patients using either of the two drugs. A total of 60 newly detected drug naïve hypertensive patients were considered for the comparison, of which 30 patients were prescribed nebivolol and the other 30 were prescribed metoprolol succinate as per the recommended dosage. Based on the data, statistical analysis was carried out using GraphPad Prism 5 and MS Excel Spreadsheet 2007. RESULT: The cost of reducing 1 mm of Hg blood pressure per day with nebivolol was 0.60, 0.70, and 1.06 INR, whereas that of metoprolol succinate was 0.93, 1.18, and 1.25 INR at their respective equivalent doses, hence significantly lower with the nebivolol group as compared to the metoprolol group (P < 0.05). CONCLUSION: This pharmacoeconomic analysis shows that nebivolol is more cost-effective as compared to metoprolol when the cost per reduction in blood pressure per day is considered. This may affect the patients economically during their long-term use of these molecules for the treatment of hypertension.

Assessment of effects of IR and IPC on activities of cytochrome P450 isozymes in rats by a five-drug cocktail approach.

BACKGROUND AND OBJECTIVE: To evaluate the effects of ischemia and reperfusion (IR) and ischemic preconditioning (IPC) on the metabolic activities of cytochrome P450 (CYP) isozymes in rats by a five-drug cocktail approach. METHODS: Cocktail approach was used to evaluate the influence of IR and IPC on the activities of CYP1A2, CYP2C9, CYP2E1, CYP2D6 and CYP3A4, which were reflected by the changes of pharmacokinetic parameters of five specific probe drugs: caffeine, chlorzoxazone, tolbutamide, metoprolol and midazolam, respectively. Rats were randomly divided into IR, IPC and sham groups, and then injected the mixture of five probe drugs. Blood samples were collected at a series of time-points and the concentrations of probe drugs in plasma were determined by a HPLC method with UV detection. The pharmacokinetic parameters were calculated by the software of DAS 2.0. RESULTS: The parameters including t(1/2ß), CLs, AUC, MRT and K10 exhibited a similar tendency for both IR and IPC groups. Compared with sham group, CLs and K10 of five probe drugs were significantly lower (p < 0.05), AUC and t(1/2ß) of five or some probe drugs were significantly increased in IR and IPC groups (p < 0.05). Compared with IPC group, CLs of five probe drugs were decreased and AUC were significantly increased in the IR group (p < 0.05). CONCLUSION: IR can variably decrease the activities of CYP isozymes in rats and this decrease can be attenuated by IPC.

Risk of emergent bradycardia associated with initiation of immediate- or slow-release metoprolol.

OBJECTIVES: To estimate and compare the risk of emergent bradycardia associated with starting immediate-release (IR) and slow-release (SR) formulations of metoprolol. DESIGN: Retrospective analysis of administrative claims data. DATA SOURCE: State of California Medicaid program (Medi-Cal) claims database. PATIENTS: A total of 31,574 adults beginning metoprolol between May 1, 2004, and November 1, 2009, without a pharmacy claim for a ß blocker within the previous 6 months of metoprolol initiation; patients with a primary or secondary diagnosis of symptomatic bradycardia, pacemaker, or implantable cardioverter-defibrillator placement before metoprolol initiation were excluded. MEASUREMENTS AND MAIN RESULTS: The study outcome was the time to first occurrence of emergent bradycardia, measured at an emergency department visit or hospitalization due to diagnosis of symptomatic bradycardia, after metoprolol initiation. We calculated the incidence and compared the risk of emergent bradycardia by using a proportional hazards model that included the metoprolol formulation with adjustment for total daily metoprolol dose and the use of other drugs as time-varying covariates, as well as demographics and comorbidities. Among 31,574 patients starting metoprolol, 18,516 (58.6%) used the IR formulation. The incidence of emergent bradycardia was 19.1/1000 person-years overall but was nearly twice as common in patients using the IR versus the SR formulation (24.1/1000 person-yrs in the IR group versus 12.9/1000 person-yrs in the SR group, unadjusted hazard ratio [HR] 1.81, 95% confidence interval [CI] 1.28-2.56). Adjustment for other drugs also associated with symptomatic bradycardia (cytochrome P450 2D6 inhibitors, class I or III antiarrhythmics, and atrioventricular node-blocking agents), metoprolol dose, and other participant characteristics somewhat attenuated the association (adjusted HR 1.48, 95% CI 1.03-2.13). CONCLUSION: The risk of emergent bradycardia associated with metoprolol initiation was higher with the IR formulation than the SR formulation, although the absolute risk was low.

Empirical shrinkage estimator for consistency assessment of treatment effects in multi-regional clinical trials.

Multi-regional clinical trials have been widely used for efficient global new drug developments. Both a fixed-effect model and a random-effect model can be used for trial design and data analysis of a multi-regional clinical trial. In this paper, we first compare these two models in terms of the required sample size, type I error rate control, and the interpretability of trial results. We then apply the empirical shrinkage estimation approach based on the random-effect model to two criteria of consistency assessment of treatment effects across regions. As demonstrated in our computations, compared with the sample estimator, the shrinkage estimator of the treatment effect of an individual region borrowing information from the other regions is much closer to the estimator of the overall treatment effect, has smaller variability, and therefore provides much higher probability for demonstrating consistency. We use a multinational trial example with time to event endpoint to illustrate the application of the method.

Simultaneous pharmacokinetics assessment of caffeine, warfarin, omeprazole, metoprolol, and midazolam intravenously or orally administered to Microminipigs.

Small minipigs (Microminipig, registered as a novel variety of pig in Japan) were developed for use in non-clinical pharmacological/toxicological studies for new drug development. To assess the pharmacokinetics of selective substrates of human cytochrome P450s in Microminipigs, caffeine (human P450 1A2), warfarin (P450 2C9), omeprazole (P450 2C19), metoprolol (P450 2D6), and midazolam (P450 3A) were administered in combination, intravenously (0.20 mg kg(-1))( )or orally (1.0 mg kg(-1)). Plasma samples obtained, up to 24 hr after dosing, from four male and four female Microminipigs were analyzed by liquid chromatography tandem mass spectrometry to estimate typical pharmacokinetic parameters for each analyte. Bioavailabilities were approximately 80% for caffeine and warfarin, but less than 10% for omeprazole, metoprolol, and midazolam. No significant differences were noted, for the five probes, in area under the plasma concentration-time curve and peak plasma concentration values obtained from male and female Microminipigs. Clearance of caffeine, warfarin, omeprazole or midazolam in vivo, mediated mainly by cytochrome P450s 1A, 2C or 3A in Microminipigs, was similar to data reported for human. However, metoprolol metabolism, mediated by P450 2D enzymes in Microminipigs, was faster than reported for in vivo human kinetic parameters and in vitro in a human liver microsomal system. The results of this study suggest that the Microminipig is a suitable animal model for use in biological experiments for comparisons of pharmacokinetics of drugs in humans. The five-probes in combination used in this study demonstrate the disposition of typical P450 drugs in Microminipigs in vivo, with the aim of use in non-clinical pharmacological/toxicological studies.

Persistence with nebivolol in the treatment of hypertension: a retrospective claims analysis.

OBJECTIVE: Examine drug persistence by evaluating the hazard of discontinuation and of switching to different antihypertensive drugs in patients initiating treatment with a recently approved ß-blocker, nebivolol, versus other ß-blockers. METHODS: This retrospective analysis included all patients diagnosed with hypertension in the MarketScan Database (January 2007 - December 2008) with at least two medical claims and no prior ß-blocker prescriptions within 6 months of the initial prescription date. Multivariate Cox proportional hazard models (adjusted for baseline differences in demographics, previous use of other antihypertensive medications, initial doses and supply of medication, and number of distinct prescriptions at baseline) were used to assess the hazard of discontinuation, defined as the first prescription gap of ≥30 days, and to assess the hazard of switching to another antihypertensive drug, defined as a prescription fill for another antihypertensive drug within 15 days before and 30 days after discontinuation of the initial ß-blocker. RESULTS: Of the 173,200 patients included in the study population, the adjusted hazard of discontinuation for nebivolol-initiated patients was 8-20% lower than that of patients who initiated treatment with atenolol (hazard ratio [HR] 0.82, p < 0.001), metoprolol (HR 0.91, p < 0.001), carvedilol (HR 0.92, p < 0.001), or other ß-blockers (HR 0.80, p < 0.001). The adjusted hazard of nebivolol-treated patients switching to a different antihypertensive medication was 12-22% lower than that of the other four ß-blocker cohorts (atenolol: HR 0.80, p < 0.001; metoprolol: HR 0.86, p < 0.001; carvedilol: HR 0.88, p < 0.001; other ß-blockers: HR 0.78, p < 0.001). Sensitivity analyses defined discontinuation as prescription gaps of ≥45 days and ≥60 days and showed a lower hazard of discontinuation among patients initiating nebivolol than among patients initiating all other drug cohorts (p < 0.001). LIMITATIONS: Comparisons of non-randomized treatment groups may be confounded by unobserved differences in patients' baseline characteristics. CONCLUSIONS: Initiation with nebivolol was associated with greater persistence than initiation with atenolol, carvedilol, metoprolol, or other ß-blockers.

[Clinical-pharmacoeconomical aspects of ß-adrenoblockers use in patients with ischemic heart disease undergoing coronary artery bypass grafting].

Aim of this study was to assess clinical and pharmacoeconomic effects of long term use of adrenoblockers in patients with ischemic heart disease (IHD) undergoing coronary artery bypass grafting. Patients with IHD (n=294) were included in open, prospective, randomized clinical trial. The follow up period was 3 years. It was noted that long term use of bisoprolol in comparison with atenolol and metoprolol was characterized by more pronounced increase of exercise tolerance, lower rate of angina recurrence and lower expenses for treatment of patients with IHD.

Farmacovigilancia activa en pacientes afiliados al sistema general de seguridad social en salud / Active pharmacosurveillance of patients affiliated to the Colombian general social security/health system

Objetivos Determinar los posibles resultados negativos asociados a la medicación mediante la metodología de búsqueda activa de posibles interacciones medicamentosas en bases de datos de pacientes afiliados al Sistema General de Seguridad Social en Salud. Métodos A partir de las bases de datos de dispensación de medicamentos de Audifarma S.A a unos 4 millones de usuarios del país, se hizo una revisión sistemática de estadísticas de una serie de medicamentos identificados por presentar interacciones de riesgo, dosis diferentes a las recomendadas o dispensación irregular. Los casos son socializados con las EPS responsables. Resultados Se encontró un caso de nefrotoxicidad por ácido zoledrónico; el 37,0 por ciento de los usuarios de clopidogrel recibían concomitantemente omeprazol, que reduce la efectividad del primero; el 29,9 por ciento de los pacientes que toman losartan están recibiendo dosis superiores a las recomendadas para su indicación; el 2,0 por ciento de los pacientes que toman metoprolol o verapamilo, los recibe simultáneamente, con riesgo de generar bradicardia sinusal, bloqueos auriculoventriculares o disfunción sistólica. Todos los casos fueron notificados a los responsables en la EPS que atienden estos pacientes. Discusión La farmacovigilancia activa permite optimizar recursos, prevenir eventos adversos que puedan potencialmente causar morbilidad importante o incluso letalidad o determinar problemas que podrían ser responsables del fracaso terapéutico. Este tipo de estrategia se anticipa a la aparición de posibles riesgos para el paciente por lo que se recomienda considerarla para reforzar los programas de vigilancia de uso de medicamentos en el país.

Objectives Determining negative results associated with medication through an active search of possible drug interactions in databases for patients affiliated to the Colombian general social security/health system. Methods Statistics related to Audifarma S.A. dispensation drug databases for about 4 million Colombian users were systematically reviewed for identifying drugs having known interactions involving risk, doses different from recommended ones or irregular dispensation. The pertinent health-care providing services were made aware of the above. Results There was one case of nephrotoxicity being caused by zoledronic acid. 37 percent of clopidogrel users concomitantly received omeprazole which reduces the former's effectiveness. 29.9 percent of patients who were taking losartan were receiving doses higher than the recommended ones. 2.0 percent of patients who were taking metoprolol or verapamil were simultaneously receiving them, at the risk of generating first-degree heart block, bradycardia, or systolic dysfunction. All these cases were notified to the pertinent health-care services. Conclusions Active pharmacosurveillance leads to resources being optimised, adverse events which can potentially cause morbidity or lethality being prevented or even determining problems which could be responsible for therapeutic failure. This type of strategy anticipates the appearance of possible risks for patients, meaning that drug use monitoring programmes in Colombia should be reinforced.

[Active pharmacosurveillance of patients affiliated to the Colombian general social security/health system]. / Farmacovigilancia activa en pacientes afiliados al sistema general de seguridad social en salud.

OBJECTIVES: Determining negative results associated with medication through an active search of possible drug interactions in databases for patients affiliated to the Colombian general social security/health system. METHODS: Statistics related to Audifarma S.A. dispensation drug databases for about 4 million Colombian users were systematically reviewed for identifying drugs having known interactions involving risk, doses different from recommended ones or irregular dispensation. The pertinent health-care providing services were made aware of the above. RESULTS: There was one case of nephrotoxicity being caused by zoledronic acid. 37 % of clopidogrel users concomitantly received omeprazole which reduces the former's effectiveness. 29.9 % of patients who were taking losartan were receiving doses higher than the recommended ones. 2.0 % of patients who were taking metoprolol or verapamil were simultaneously receiving them, at the risk of generating first-degree heart block, bradycardia, or systolic dysfunction. All these cases were notified to the pertinent health-care services. CONCLUSIONS: Active pharmacosurveillance leads to resources being optimised, adverse events which can potentially cause morbidity or lethality being prevented or even determining problems which could be responsible for therapeutic failure. This type of strategy anticipates the appearance of possible risks for patients, meaning that drug use monitoring programmes in Colombia should be reinforced.

[Assessment of dynamics of the autonomic cardiovascular system regulation based on low-frequency rhythm synchronization in patients with ischemic heart diseases complicated by myocardial infarction treated with metoprolol].

AIM: To develop a procedure for assessing the adequacy of metoprolol use in patients with coronary heart disease (CHD) on the basis of synchronization of 0.1-Hz rhythms in cardiac rhythm variability (CRV) and vascular blood filling in the microcirculatory bed (MCB). Materials and methods. 43 patients with CHD (age 63 +/- 8 years), who had sustained myocardial infarction about 6 months before, were examined. Synchronous registration of ECG and a pulsogram were made during an orthostatic test before and after therapy with metoprolol in the maximum tolerable doses during 3 months. The presence of synchronization of 0.1-Hz rhythms identified from a series of R-R intervals and the pulsogram was determined from the difference of phases; the total percent of synchronization (S) was estimated. RESULTS: The authors identified 2 groups of CHD patients: those with positive (n=21) and negative (n=16) orthostatic S, trends during treatment. The groups were matched by major clinical characteristics. There was an inverse relationship between the values of S, in the lying and standing position prior to or following treatment. It is suggested that there is the optimum range of 0.1-Hz rhythm synchronization values in the cardiovascular system during beta-blocker therapy in patients with CHD. CONCLUSION: There is a possibility applying an objective approach to assessing the adequacy of metoprolol treatment in CHD patients on the basis of synchronization of 0.1-Hz fluctuations in variations CR V and vascular blood filling in MCB.

Valsartan versus lisinopril or extended-release metoprolol in preventing cardiovascular and renal events in patients with hypertension.

PURPOSE: The objective of this study was to compare cardiovascular and renal events in patients with hypertension receiving the angiotensin II-receptor blocker valsartan versus those receiving the angiotensin-converting-enzyme lisinopril or the beta-blocker metoprolol succinate in an extended-release formulation. METHODS: A retrospective study was conducted using a health insurance claims database spanning the period from January 1997 through December 2003 and representing approximately 40 million members enrolled in over 70 health plans across the United States. Study subjects included all persons in the database with two or more outpatient prescriptions for valsartan, lisinopril, or extended-release metoprolol and two or more prior claims with a diagnosis of hypertension. Those with a history of major cardiovascular or renal events (diagnosis of myocardial infarction, stroke, heart failure, ventricular arrhythmias, or cardiac arrest; coronary revascularization procedure; diagnosis of renal failure; or dialysis or kidney transplantation) or using other antihypertensive medications except diuretics during the 12 months before treatment with valsartan, lisinopril, or extended-release metoprolol were excluded. Risks of major cardiovascular or renal event during follow-up were analyzed using Cox proportional hazards regression. RESULTS: A total of 29,357 antihypertensive patients were identified who initiated therapy with valsartan (n = 6,645), lisinopril (n = 17,320), or extended-release metoprolol (n = 5,392). In multivariate analyses, therapy with valsartan was associated with a significantly lower risk of a major cardiovascular or renal event versus extended-release metoprolol (heart rate [HR], 0.70; 95% confidence interval [CI], 0.56-0.87; p = 0.0015). Patients receiving valsartan had a nominally lower risk of a major cardiovascular or renal event than those receiving lisinopril, although this difference was not statistically significant (HR, 0.89; 95% CI, 0.74-1.07; p = 0.1987). CONCLUSION: Results of this observational study suggest that the use of valsartan may reduce the risk of major cardiovascular and renal events compared with extended-release metoprolol.

Assessment of left ventricular function and mass in patients undergoing computed tomography (CT) coronary angiography using 64-detector-row CT: comparison to magnetic resonance imaging.

PURPOSE: To quantify left ventricular function and mass derived from retrospectively ECG-gated 64-detector-row computed tomography coronary angiography data sets in comparison to cine magnetic resonance (MR) imaging as the reference standard. We hypothesized that the administration of beta-blockers prior to multidetector computed tomography (MDCT) coronary angiography has a significant impact on left ventricular functional parameters. MATERIAL AND METHODS: Multiplanar reformations in the short-axis orientation were calculated from axial contrast-enhanced CT images in 21 patients (16 male, five female; age range 41-75 years, mean 64.3+/-6.8 years) referred for CT coronary angiography. Patients whose heart rates exceeded 60 bpm received 5 mg bisoprolol orally 1 hour before the MDCT examination. In case of insufficient heart-rate reduction, up to four vials (20 mg) of metoprolol were injected intravenously. The end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), cardiac output (CO), and left ventricular mass (LVM) of the reformatted images were analyzed compared to volumetric measurements based on continuous short-axis steady-state free-precession cine MR sequences (TR 3 ms, TE 1.5 ms, FA 60 degrees ). RESULTS: On average, each patient received 15.5 mg metoprolol (range 0-20 mg) and 3.85 mg bisoprolol (range 0-5 mg). The mean heart rate was 56+/-5 bpm during CT and 73+/-9 bpm during MRI examination. This difference was statistically significant (P<0.05). Mean EDV and ESV measured on MDCT were significantly higher compared to MR (MDCT vs. MR: EDV 164.2+/-52.5 vs. 144.2+/-46.7 ml, ESV 77.3+/-46.6 vs. 63.8+/-47.3 ml; P<0.05). Mean EF and CO derived from MDCT images were significantly lower compared to MR (MDCT vs. MR: EF 55.4+/-11.8 vs. 59.3+/-15.4%, CO 4822+/-779 vs. 5755+/-1267 ml; P<0.05). Mean SV and LVM were not significantly different between both methods (MDCT vs. MR: SV 86.8+/-18.1 vs. 80.3+/-15.6 ml, P = 0.44; LVM 132.4+/-42.5 vs. 138.7+/-39.1 g, P = 0.31). CONCLUSION: Left ventricular volumes assessed by the newest-generation MDCT scanners are significantly higher compared with MRI, whereas ejection fraction and cardiac output are significantly lower in MDCT. This appears to be a result of the frequent application of beta-blockers prior to MDCT examinations.