A retrospective evaluation of the efficacy of intravenous bumetanide and comparison of potency with furosemide

Role of Monovalent Ions in the NKCC1 Inhibition Mechanism Revealed through Molecular Simulations

The secondary active Na-K-Cl cotransporter 1 (NKCC1) promotes electroneutral uptake of two chloride ions, one sodium ion and one potassium ion. NKCC1 regulates Cl^- homeostasis, thus being implicated in transepithelial water transport and in neuronal excitability. Aberrant NKCC1 transport is linked to a variety of human diseases. The loop diuretic drugs bumetanide, furosemide, azosemide and ethacrynic acid target NKCC1, but are characterized by poor selectivity leading to severe side effects. Despite its therapeutic importance, the molecular details of the NKCC1 inhibition mechanism remain unclear. Using all-atom simulations, we predict a putative binding mode of these drugs to the zebrafish (z) and human (h) NKCC1 orthologs. Although differing in their specific interactions with NKCC1 and/or monovalent ions, all drugs can fit within the same cavity and engage in hydrophobic interactions with M304/M382 in z/hNKCC1, a proposed ion gating residue demonstrated to be key for bumetanide binding. Consistent with experimental evidence, all drugs take advantage of the K⁺/Na⁺ ions, which plastically respond to their binding. This study not only provides atomic-level insights useful for drug discovery campaigns of more selective/potent NKCC1 inhibitors aimed to tackle diseases related to deregulated Cl^- homeostasis, but it also supplies a paradigmatic example of the key importance of dynamical effects when drug binding is mediated by monovalent ions.

Treatment outcomes of bumetanide continuous infusion: A systematic review and meta-analysis

The clinical use of continuous bumetanide infusion for acute heart failure and volume overload is common. However, there is not enough supporting evidence for the use of continuous bumetanide infusion. Thus, we conducted this systematic review and meta-analysis aiming to describe the treatment outcomes of continuous bumetanide infusion. We searched Ovid MEDLINE, EMBASE and the Cochrane Library for eligible publications. Inclusion criteria were patients age ≥18 years with bumetanide infusion for heart failure, acute kidney injury (AKI) or volume overload. From 1564 citations, three studies (n = 94 patients) were included in the systematic review and meta-analysis. The mean dose of bumetanide was 1.08 ± 0.43 mg/hour with a mean treatment duration of 45.09 ± 10.12 hours. Mean urine output in response to continuous bumetanide infusion was 1.88 mL/kg/hour (95% confidence interval [CI], 1.72-2.05). The incidence of AKI with continuous bumetanide infusion was 24.7% (95% CI, 8.2-54.6). By using Pearson's correlation coefficient, increasing doses of bumetanide were correlated with increased urine output (P = .026) and increased incidence of AKI (P < .01). There was no correlation between increasing urine output and the incidence of AKI (P = .739). In conclusion, with available evidence, continuous bumetanide infusion may be used in the treatment of acute heart failure or volume overload with close monitoring for new-onset or worsening AKI.

Acute Hyperglycemia Aggravates Lung Injury via Activation of the SGK1-NKCC1 Pathway

Acute lung injury (ALI) is characterized by severe hypoxemia and has significantly high mortality rates. Acute hyperglycemia occurs in patients with conditions such as sepsis or trauma, among others, and it results in aggravated inflammation and induces damage in patients with ALI. Regulation of alveolar fluid is essential for the development and resolution of pulmonary edema in lung injury. Pulmonary sodium-potassium-chloride co-transporter 1 (NKCC1) regulates the net influx of ions and water into alveolar cells. The activation of with-no-lysine kinase 4 (WNK4), STE20/SPS1-related proline/alanine rich kinase (SPAK) and the NKCC1 pathway lead to an increase in the expression of NKCC1 and aggravation of ALI. Moreover, hyperglycemia is known to induce NKCC1 expression via the activation of the serum-glucocorticoid kinase 1 (SGK1)-NKCC1 pathway. We aim to evaluate the influence of acute hyperglycemia on the SGK1-NKCC1 pathway in ALI. ALI was induced using a high tidal volume for four hours in a rat model. Acute hyperglycemia was induced by injection with 0.5 mL of 40% glucose solution followed by continuous infusion at 2 mL/h. The animals were divided into sham, sham+ hyperglycemia, ALI, ALI + hyperglycemia, ALI + inhaled bumetanide (NKCC1 inhibitor) pretreatment, ALI + hyperglycemia + inhalational bumetanide pretreatment, and ALI + hyperglycemia + post-ALI inhalational bumetanide groups. Severe lung injury along with pulmonary edema, alveolar protein leakage, and lung inflammation was observed in ALI with hyperglycemia than in ALI without hyperglycemia. This was concurrent with the higher expression of pro-inflammatory cytokines, infiltration of neutrophils and alveolar macrophages (AM) 1, and NKCC1 expression. Inhalational NKCC1 inhibitor significantly inhibited the SGK1-NKCC1, and WNK4-SPAK-NKCC1 pathways. Additionally, it reduced pulmonary edema, inflammation, levels of pro-inflammatory cytokines, neutrophils and AM1 and increased AM2. Therefore, acute hyperglycemia aggravates lung injury via the further activation of the SGK1-NKCC1 pathway. The NKCC1 inhibitor can effectively attenuate lung injury aggravated by acute hyperglycemia.

Quality of acute heart failure treatment in France: Data from REseau Nord-Alpin des Urgences (RENAU)

BACKGROUND

Although mortality due to acute heart failure has decreased, its prevalence in France is still high. The aim of this study was to examine the quality of acute heart failure treatment in French emergency departments (EDs) with reference to subsequently published European Society of Cardiology (ESC) recommendations.

METHODS

The medical records of patients with acute pulmonary oedema (as a marker for acute heart failure) admitted to the EDs of 11 French hospitals in 2013 were reviewed retrospectively.

RESULTS

A total of 834 patients were included (median [interquartile range] age 84 [78-89] years; 48.6% male). Rates of compliance of initial management in 2013 to subsequently published 2015 recommendations were as follows: (1) thoracic ultrasound was performed in 17.3%; (2) loop diuretics were given in 75.9%; at a correct dose (among those for whom this was calculable) in 40.0% (3); intravenous nitrates were given in 21.7% of patients with systolic blood pressure>110mmHg; (4) non-invasive ventilation was initiated in 22.0% of patients with respiratory distress. Discharge summaries most often lacked a scheduled cardiologist follow-up (89.4%) and discharge patient weight (78.9%).

CONCLUSIONS

The early management of patients with acute pulmonary oedema (as a marker of acute heart failure) in France in 2013 was quite different to recommendations published in 2015. A programme to implement the new recommendations is in place, and a repeat evaluation will be conducted in 2017.

Subdiuretic dose of furosemide enhances albuterol effects in asthmatic mice rather than bumetanide

BACKGROUND

One of the loop diuretics, furosemide, was found useful in bronchial asthma. It enhanced anti-asthmatic effects of albuterol. The underlying mechanism is still unclear.

OBJECTIVE

This study was planned to investigate whether the enhancing effect of furosemide for albuterol in ovalbumin-induced asthmatic BALB/c mice is diuretic-related or not.

METHODS

Two sets of experiments were performed. In the first, effects of inhaled subdiuretic doses of furosemide and bumetanide (another loop diuretic) were compared. Treatments (mg/mL) were given as 15 minute-inhalation before final ovalbumin provocation as follows: albuterol (2.5), furosemide (0.08), bumetanide (0.005), (albuterol+furosemide, 2.5+0.08), and (albuterol+bumetanide, 2.5+0.005). Airway hyperreactivity (AHR) to inhaled methacholine, levels of IL-6, TNF-α, and differential white blood cells in bronchoalveolar lavage fluid (BALF), and lung histopathology were evaluated. In the second set, effects of oral diuretic doses (mg/kg) of furosemide (10) and bumetanide (0.25) were given before final ovalbumin provocation. Urine volume and asthma parameters were measured.

RESULTS

Ovalbumin-asthmatic mice showed significant increases in AHR, levels of IL-6, TNF-α, and inflammatory cells in BALF, and lung inflammatory cell infiltration. Inhaled furosemide significantly decreased these changes while inhaled bumetanide failed. Albuterol and albuterol+bumetanide significantly decreased these changes more than furosemide while albuterol+furosemide produced the most significant decreases. Both oral furosemide and bumetanide exerted equivalent diuretic effects but failed to improve asthma.

CONCLUSIONS

Inhaled subdiuretic dose of furosemide enhanced effects of albuterol more in ovalbumin-asthmatic mice rather than bumetanide, while oral diuretic doses of both drugs failed to improve asthma, indicating that this enhancing effect is not diuretic-related.

Inhibition of NKCC1 Modulates Alveolar Fluid Clearance and Inflammation in Ischemia-Reperfusion Lung Injury via TRAF6-Mediated Pathways

Background: The expression of Na-K-2Cl cotransporter 1 (NKCC1) in the alveolar epithelium is responsible for fluid homeostasis in acute lung injury (ALI). Increasing evidence suggests that NKCC1 is associated with inflammation in ALI. We hypothesized that inhibiting NKCC1 would attenuate ALI after ischemia-reperfusion (IR) by modulating pathways that are mediated by tumor necrosis-associated factor 6 (TRAF6).

Methods: IR-ALI was induced by producing 30 min of ischemia followed by 90 min of reperfusion in situ in an isolated and perfused rat lung model. The rats were randomly allotted into four groups comprising two control groups and two IR groups with and without bumetanide. Alveolar fluid clearance (AFC) was measured for each group. Mouse alveolar MLE-12 cells were cultured in control and hypoxia-reoxygenation (HR) conditions with or without bumetanide. Flow cytometry and transwell monolayer permeability assay were carried out for each group.

Results: Bumetanide attenuated the activation of p-NKCC1 and lung edema after IR. In the HR model, bumetanide decreased the cellular volume and increased the transwell permeability. In contrast, bumetanide increased the expression of epithelial sodium channel (ENaC) via p38 mitogen-activated protein kinase (p38 MAPK), which attenuated the reduction of AFC after IR. Bumetanide also modulated lung inflammation via nuclear factor-κB (NF-κB). TRAF6, which is upstream of p38 MAPK and NF-κB, was attenuated by bumetanide after IR and HR.

Conclusions: Inhibition of NKCC1 by bumetanide reciprocally modulated epithelial p38 MAPK and NF-κB via TRAF6 in IR-ALI. This interaction attenuated the reduction of AFC via upregulating ENaC expression and reduced lung inflammation.

Aggressive Versus Conservative Initial Diuretic Dosing in the Emergency Department for Acute Decompensated Heart Failure

Background:Intravenous (IV) loop diuretics are recommended to relieve vascular congestion in patients with acute decompensated heart failure (ADHF); however, initial dosing is often empirical. Strong evidence supporting individualized diuretic dosing in the emergency department (ED) is lacking. Objective: The purpose of this study was to compare the efficacy and safety of aggressive (≥2 daily home doses) and conservative (<2 daily home doses) initial doses of loop diuretic. Methods: This was a retrospective cohort study in adult patients presenting to the ED with ADHF at an academic medical center from Apri 2015 to September 2015. The primary outcome was time to transition from IV to oral diuretics. Results: A total of 91 patients were included (aggressive dosing, n = 44; conservative dosing, n = 47). Mean time to transition from IV to oral diuretics was 67.9 hours in the aggressive group compared with 88.1 hours in the conservative group ( P = 0.049). Mean hospital length of stay (LOS) was 119.5 hours in the aggressive group versus 123.0 hours in the conservative group ( P = 0.799). No differences were observed between the mean urine output ( P = 0.829), change in body weight ( P = 0.528), or serum creatinine ( P = 0.135). Conclusion: Patients who received an aggressive initial diuretic dose in the ED had a significantly faster time to oral diuretic therapy without any significant differences in hospital LOS, urine output, change in body weight, and renal function when compared with conservative dosing.

Cardiovascular Drug Shortages: Predominant Etiologies, Clinical Implications, and Management Strategies

OBJECTIVE

To review the literature surrounding the incidence, significance, and management of cardiovascular (CV) drug shortages.

DATA SOURCES

A literature search was conducted using all available indexing databases from January 1996 to August 2013, coupled with assessments of the ASHP (American Society of Health System Pharmacists) and Food and Drug Administration Web sites designated to drug shortages. Data were also gathered through a review of listservs discussing this topic.

DATA SYNTHESIS

CV drug shortages are among the top 5 national drug class shortages that are posing a threat to patient care and public health. When a drug shortage occurs, it requires modifications to prescribing and the method medications are processed by the pharmacy. These necessary yet cumbersome changes can potentially result in less-than-desirable prescribing options and increases in personnel time because of administrative and dispensing obstacles. Any one of these has the potential to increase costs and/or lead to worse outcomes. Several factors have been shown to contribute to these shortages, including manufacturing delays, increased demand, medication discontinuations, and lack of raw materials. In this article, we review 13 of the critical CV drug shortages, describe their role in therapy, discuss the reasons for the shortage, define their impact on patient care, and recommend alternative therapies.

CONCLUSIONS

CV drug shortages are common and can potentially lead to deleterious patient outcomes. Institutions should develop plans for early identification, management, and resolution to minimize the clinical sequelae associated with drug shortages.

Pharmacotherapeutic targeting of cation-chloride cotransporters in neonatal seizures

Seizures are a common manifestation of acute neurologic insults in neonates and are often resistant to the standard antiepileptic drugs that are efficacious in children and adults. The paucity of evidence-based treatment guidelines, coupled with a rudimentary understanding of disease pathogenesis, has made the current treatment of neonatal seizures empiric and often ineffective, highlighting the need for novel therapies. Key developmental differences in γ-aminobutyric acid (GABA)ergic neurotransmission between the immature and mature brain, and trauma-induced alterations in the function of the cation-chloride cotransporters (CCCs) NKCC1 and KCC2, probably contribute to the poor efficacy of standard antiepileptic drugs used in the treatment of neonatal seizures. Although CCCs are attractive drug targets, bumetanide and other existing CCC inhibitors are suboptimal because of pharmacokinetic constraints and lack of target specificity. Newer approaches including isoform-specific NKCC1 inhibitors with increased central nervous system penetration, and direct and indirect strategies to enhance KCC2-mediated neuronal chloride extrusion, might allow therapeutic modulation of the GABAergic system for neonatal seizure treatment. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.