The clinical pharmacology of loop diuretics in the pediatric patient

Furosemide in pediatric intensive care: a retrospective cohort analysis

Introduction

Furosemide is the most commonly used medication in pediatric intensive care. Growing data indicates improved hemodynamic stability and efficacy of furosemide infusions compared to intermittent injections, thereby suggesting furosemide infusions might be considered as first line therapy in critically ill, paediatric patients. The objective of this study is to examine furosemide treatment as either continuous infusions or intermittent injections and subsequent patient outcomes.

Methods

This is a retrospective cohort analysis of patients treated in a pediatric intensive care unit (ICU) over a nine year period (July 31st 2006 and July 31, 2015). Eligible patients were admitted to either the general pediatric or cardiac specific ICU for a duration of at least 6 hours and who received intravenous furosemide treatment.

Results

A total of 7,478 patients were identified who received a total of 118,438 furosemide administrations for a total of 113,951 (96%) intermittent doses and 4,487 (4%) infusions running for a total of 1,588,750 hours. A total of 5,996 (80%) patients received exclusively furosemide injections and 1,482 (20%) patients received at least one furosemide infusion. A total of 193 patients died during ICU admission, amounting to 87 (6%) of the 1,482 patients who received an infusion and 106 (2%) of the 5,996 who received intermittent injections. Multivariable regression analysis showed no statistically significant decrease in adjusted mortality for patients who received furosemide injections compared to furosemide infusions (aOR 1.20, CI 0.76-1.89).

Discussion

This retrospective study observed similar mortality for patients who received furosemide infusions compared to furosemide injections. More research on furosemide in the ICU could provide insights on fluid management, drug effectiveness, and pharmacologic stewardship for critically ill children.

Hydroxyapatite Nanorods Based Drug Delivery Systems for Bumetanide and Meloxicam, Poorly Water Soluble Active Principles

Poorly water-soluble drugs represent a challenge for the pharmaceutical industry because it is necessary to find properly tuned and efficient systems for their release. In this framework, organic-inorganic hybrid systems could represent a promising strategy. A largely diffused inorganic host is hydroxyapatite (HAP, Ca10(PO4)6(OH)2), which is easily synthesized with different external forms and can adsorb different kinds of molecules, thereby allowing rapid drug release. Hybrid nanocomposites of HAP nanorods, obtained through hydrothermal synthesis, were prepared with two model pharmaceutical molecules characterized by low and pH-dependent solubility: meloxicam, a non-steroidal anti-inflammatory drug, and bumetanide, a diuretic drug. Both hybrids were physically and chemically characterized through the combined use of X-ray powder diffraction, scanning electron microscopy with energy-dispersive spectroscopy, differential scanning calorimetry, and infrared spectroscopy measurements. Then, their dissolution profiles and hydrophilicity (contact angles) in different media as well as their solubility were determined and compared to the pure drugs. This hybrid system seems particularly suitable as a drug carrier for bumetanide, as it shows higher drug loading and good dissolution profiles, while is less suitable for meloxicam, an acid molecule.

New frontiers in neonatal red blood cell transfusion research

Red blood cell (RBC) transfusions are common in neonates requiring intensive care. Recent studies have compared restricted versus liberal transfusion guidelines, but limitations exist on evaluations of outcomes in populations that never required a transfusion compared to those receiving any transfusion. Although there are well-established risks associated with RBC transfusions, new data has emerged that suggests additional clinically relevant associations, including adverse neurodevelopmental outcomes, donor sex differences, and inflammation or immunosuppression. Further research is needed to delineate the magnitude of these risks and to further improve the safety of transfusions. The goal of this review is to highlight underappreciated, yet clinically important risks associated with neonatal RBC transfusions and to introduce several areas in which neonates may uniquely benefit from alterations in practice.

The loop diuretic torasemide but not azosemide potentiates the anti-seizure and disease-modifying effects of midazolam in a rat model of birth asphyxia

Loop diuretics such as furosemide and bumetanide, which act by inhibiting the Na-K-2Cl cotransporter NKCC2 at the thick ascending limb of the loop of Henle, have been shown to exert anti-seizure effects. However, the exact mechanism of this effect is not known. For bumetanide, it has been suggested that inhibition of the NKCC isoform NKCC1 in the membrane of brain neurons may be involved; however, NKCC1 is expressed by virtually all cell types in the brain, which makes any specific targeting of neuronal NKCC1 by bumetanide impossible. In addition, bumetanide only poorly penetrates the brain. We have previously shown that loop diuretics azosemide and torasemide also potently inhibit NKCC1. In contrast to bumetanide and furosemide, azosemide and torasemide lack a carboxylic group, which should allow them to better penetrate through biomembranes by passive diffusion. Because of the urgent medical need to develop new treatments for neonatal seizures and their adverse outcome, we evaluated the effects of azosemide and torasemide, administered alone or in combination with phenobarbital or midazolam, in a rat model of birth asphyxia and neonatal seizures. Neither diuretic suppressed the seizures when administered alone but torasemide potentiated the anti-seizure effect of midazolam. Brain levels of torasemide were below those needed to inhibit NKCC1. In addition to suppressing seizures, the combination of torasemide and midazolam, but not midazolam alone, prevented the cognitive impairment of the post-asphyxial rats at 3 months after asphyxia. Furthermore, aberrant mossy fiber sprouting in the hippocampus was more effectively prevented by the combination. We assume that either an effect on NKCC1 at the blood-brain barrier and/or cells in the periphery or the NKCC2-mediated diuretic effect of torasemide are involved in the present findings. Our data suggest that torasemide may be a useful option for improving the treatment of neonatal seizures and their adverse outcome.

Diuretics in pediatrics

Diuretics are frequently prescribed drugs and help managing several pathological conditions, including acute and chronic kidney disease, nephrotic syndrome, congestive heart failure, ascites, systemic and pulmonary hypertension. Diuretic classes include among others osmotic diuretics and carboanhydrase inhibitors, loop diuretics, thiazides, and potassium-sparing diuretics. In this educational article, we aim at reviewing indications, mechanisms of action, and side effects, as well as basic pharmacokinetics considerations and data on diuretics in children, supporting practicing clinicians in choosing (and understanding the background of) the best-suited diuretic regimen for the individual patient. Newer diuretic classes like vaptans and sodium glucose type 2 cotransporter inhibitors, the recent controversies on hydrochlorothiazide, and the issue of diuretic resistance, will also be briefly addressed.

CONCLUSION

This educational review offers a didactical overview of diuretics in Pediatrics.

WHAT IS KNOWN

• Diuretics are frequently prescribed drugs in both adults and children. • They increase water and sodium excretion, reducing fluid overload.

WHAT IS NEW

• This article reviews indications, mechanisms of action, side effects, and basic pharmacokinetics facts on diuretics in Paediatrics. • It also addresses current issues, like the management of diuretic resistance, the recent controversy on hydrochlorothiazide, and the novel classes vaptans and gliflozins.

3D printed furosemide and sildenafil tablets: Innovative production and quality control

Three-dimensional (3D) printing of pharmaceuticals has the potential to revolutionise personalised medicine but is as yet largely unexplored. A proof-of-concept study of a novel heated, piston-driven semi-solid extrusion 3D printer was performed by producing furosemide and sildenafil tablets for paediatric patients. The average weight of the tablets was 141.1 mg (RSD 1.26%). The acceptance values of the content uniformity were 4.2-10.6 (concentration RSD 0.41-0.63%), 4.8-8.9 (concentration RSD 0.76-0.97%) and 6.6-9.2 (concentration RSD 0.94-1.44%) for furosemide 2 mg, 10 mg and sildenafil 4 mg, respectively. The dissolution rate limiting step was the dissolving and eroding of the tablet matrix and showed an immediate release. The tablets complied to the requirements of the European Pharmacopoeia (EP) for uniformity of mass (EP 2.9.5), content uniformity (EP 2.9.40) and conventional release (EP 2.9.3). While they complied, not all of these quality tests for tablets might be suitable for 3D printed tablets due to the layering of the tablets and the small batch production. To assess adequate layer adhesion adjusted friability (EP 2.9.7) and resistance to crushing (EP 2.9.8) tests are proposed.

Contribution of Uptake and Efflux Transporters to Oral Pharmacokinetics of Furosemide

Furosemide is a widely used diuretic for treating excessive fluid accumulation caused by disease conditions like heart failure and liver cirrhosis. Furosemide tablet formulation exhibits variable pharmacokinetics (PK) with bioavailability ranging from 10 to almost 100%. To explain the variable absorption, we integrated the physicochemical, in vitro dissolution, permeability, distribution, and the elimination parameters of furosemide in a physiologically-based pharmacokinetic (PBPK) model. Although the intravenous PBPK model reasonably described the observed in vivo PK data, the reported low passive permeability failed to capture the observed data after oral administration. To mechanistically justify this discrepancy, we hypothesized that transporter-mediated uptake contributes to the oral absorption of furosemide in conjunction with passive permeability. Our in vitro results confirmed that furosemide is a substrate of intestinal breast cancer resistance protein (BCRP), multidrug resistance-associated protein 4 (MRP4), and organic anion transporting polypeptide 2B1 (OATP2B1), but it is not a substrate of P-glycoprotein (P-gp) and MRP2. We then estimated the net transporter-mediated intestinal uptake and integrated it into the PBPK model under both fasting and fed conditions. Our in vitro data and PBPK model suggest that the absorption of furosemide is permeability-limited, and OATP2B1 and MRP4 are important for its permeability across intestinal membrane. Further, as furosemide has been proposed as a probe substrate of renal organic anion transporters (OATs) for assessing clinical drug-drug interactions (DDIs) during drug development, the confounding effects of intestinal transporters identified in this study on furosemide PK should be considered in the clinical transporter DDI studies.

Antihypertensive agents: a long way to safe drug prescribing in children

Recently updated clinical guidelines have highlighted the gaps in our understanding and management of pediatric hypertension. With increased recognition and diagnosis of pediatric hypertension, the use of antihypertensive agents is also likely to increase. Drug selection to treat hypertension in the pediatric patient population remains challenging. This is primarily due to a lack of large, well-designed pediatric safety and efficacy trials, limited understanding of pharmacokinetics in children, and unknown risk of prolonged exposure to antihypertensive therapies. With newer legislation providing financial incentives for conducting clinical trials in children, along with publication of pediatric-focused guidelines, literature available for antihypertensive agents in pediatrics has increased over the last 20 years. The objective of this article is to review the literature for safety and efficacy of commonly prescribed antihypertensive agents in pediatrics. Thus far, the most data to support use in children was found for angiotensin-converting enzyme inhibitors (ACE-I), angiotensin receptor blockers (ARB), and calcium channel blockers (CCB). Several gaps were noted in the literature, particularly for beta blockers, vasodilators, and the long-term safety profile of antihypertensive agents in children. Further clinical trials are needed to guide safe and effective prescribing in the pediatric population.

Pharmacoepidemiology of Furosemide in the Neonatal Intensive Care Unit

BACKGROUND

Furosemide is commonly used off-label in the neonatal intensive care unit (NICU), but current dosing practices vary widely.

OBJECTIVES

To describe dosing practices including route, dose, and duration of exposure to furosemide in a large number of community and tertiary NICUs across North America.

METHOD

Using the Pediatrix Medical Group Clinical Data Warehouse, we identified infants who received ≥1 dose of furosemide between 1997 and 2016. We excluded infants with incomplete dosing data. We calculated average daily furosemide dose, cumulative dose, total days of exposure, and maximum daily dose. We compared dosing between infants born at <32 weeks gestational age (GA) and ≥32 weeks GA.

RESULTS

A total of 18,572 infants had complete dosing data. The median (interquartile value) postnatal age at first exposure was 11 days (4, 26), the median maximum daily dose was 1.0 mg/kg (0.97, 1.6), the median average daily dose was 1.0 mg/kg (0.88, 1.1), and the median cumulative dose was 2.0 mg/kg (1.0, 4.5). The median total duration of exposure was 2 days (1, 4). A total of 177 (1%) infants received ≥4 mg/kg/day of furosemide. Infants born <32 weeks GA were an older age at initial furosemide exposure compared to those born ≥32 weeks GA: 19 versus 4 days, p < 0.001.

CONCLUSIONS

Most infants received short courses of furosemide within the labeled dosing parameters. Further studies are needed to assess the safety and efficacy of furosemide in the NICU.

Avoiding Furosemide Ototoxicity Associated With Single-Ventricle Repair in Young Infants

OBJECTIVE

To reduce bilateral delayed-onset progressive sensory permanent hearing loss using a systems-wide quality improvement project with adherence to best practice for the administration of furosemide.

DESIGN

Prospective cohort study with regular audiologic follow-up assessment of survivors both before and after a 2007-2008 quality improvement practice change.

SETTING

The referral center in Western Canada for complex cardiac surgery, with comprehensive multidisciplinary follow-up by the Complex Pediatric Therapies Follow-up Program.

PATIENTS

All consecutive patients having single-ventricle palliative cardiac surgery at age 6 weeks old or younger.

INTERVENTIONS

A 2007-2008 quality improvement practice change consisted of a Parenteral Drug Monograph revision indicating slow IV administration of furosemide, an educational program, and an evaluation.

MEASUREMENTS AND MAIN RESULTS

The outcome measure was the prevalence of permanent hearing loss by 4 years old. Firth multiple logistic regression compared pre (1996-2008) to post (2008-2012) practice change occurrence of permanent hearing loss, adjusting for confounding variables, including all hospital days, extracorporeal membrane oxygenation, cardiopulmonary bypass time, age at first surgery, dialysis, and sepsis. From 1996 to 2012, 259 infants had single-ventricle palliative surgery at age 6 weeks old or younger, with 173 (64%) surviving to age 4 years. Of survivors, 106 (61%) were male, age at surgery was 11.6 days (9.0 d), and total hospitalization days by age 4 years were 64 (42); 18 (10%) had cardiopulmonary resuscitation and 38 (22%) had sepsis at any time. All 173 (100%) had 4-year follow-up. Pre- to postpractice change permanent hearing loss dropped from 17/100 (17%) to 0/73 (0%) of survivors. On Firth multiple logistic regression, the only variable statistically associated with permanent hearing loss was the pre- to postpractice change time period (odds ratio, 0.03; 95% CI, 0-0.35; p = 0.001).

CONCLUSIONS

A practice change to ensure slow IV administration of furosemide eliminated permanent hearing loss. Centers caring for critically ill infants, particularly those with single-ventricle anatomy or hypoxia, should review their drug administration guidelines and adhere to best practice for administration of IV furosemide.

Systematic analysis and identification of unexpected interactions from the neuroprotein drug interactome in hydrocephalus pharmacological intervention

Hydrocephalus is a neurological condition caused by an abnormal accumulation of cerebrospinal fluid; pharmacological intervention of the disease has been found to elicit a variety of adverse drug reactions (ADRs) in central nervous system (CNS) by unexpectedly targeting certain functional neuroproteins. Here, a systematic neuroprotein drug interactome (SNDI) is created for 11 hydrocephalus drugs/metabolites plus 20 control drugs across 518 druggable pockets on the surface of 472 CNS neuroproteins via a large-scale molecular docking approach. Heuristic clustering analysis of the SNDI profile divides the 31 investigated drug ligands into a distinct panel and a background panel; the former consists of two hydrocephalus drugs (Furosemide and Triamterene) and their respective metabolites (Furosemide glucuronide and Hydroxytriamterene) that are inferred to have generally high affinity towards the whole array of neuroprotein pockets. A total of 13 neuroproteins are enriched in gene ontology semantic mining as putative unexpected targets of the distinct panel, and their intermolecular interactions with hydrocephalus drugs/metabolites are investigated in detail using dynamics simulation and energetics analysis. We also perform kinase assay and viability test to substantiate the interactome analysis. It is found that the Furosemide and Triamterene have significant cytotoxic effects on normal human astrocytes, in which the Triamterene can inhibit the neurokinase ROCK2, a representative of putative unexpected targets, with a high activity, which is comparable with the sophisticated ROCK2 inhibitor Fasudil.

Azosemide is more potent than bumetanide and various other loop diuretics to inhibit the sodium-potassium-chloride-cotransporter human variants hNKCC1A and hNKCC1B

The Na⁺–K⁺–2Cl⁻ cotransporter NKCC1 plays a role in neuronal Cl⁻ homeostasis secretion and represents a target for brain pathologies with altered NKCC1 function. Two main variants of NKCC1 have been identified: a full-length NKCC1 transcript (NKCC1A) and a shorter splice variant (NKCC1B) that is particularly enriched in the brain. The loop diuretic bumetanide is often used to inhibit NKCC1 in brain disorders, but only poorly crosses the blood-brain barrier. We determined the sensitivity of the two human NKCC1 splice variants to bumetanide and various other chemically diverse loop diuretics, using the Xenopus oocyte heterologous expression system. Azosemide was the most potent NKCC1 inhibitor (IC₅₀s 0.246 µM for hNKCC1A and 0.197 µM for NKCC1B), being about 4-times more potent than bumetanide. Structurally, a carboxylic group as in bumetanide was not a prerequisite for potent NKCC1 inhibition, whereas loop diuretics without a sulfonamide group were less potent. None of the drugs tested were selective for hNKCC1B vs. hNKCC1A, indicating that loop diuretics are not a useful starting point to design NKCC1B-specific compounds. Azosemide was found to exert an unexpectedly potent inhibitory effect and as a non-acidic compound, it is more likely to cross the blood-brain barrier than bumetanide.

Development of Tolerance to Chronic Intermittent Furosemide Therapy in Pediatric Patients

OBJECTIVES

The purpose of this study is to describe whether tolerance develops in pediatric patients receiving chronic intermittent furosemide therapy, to characterize when it occurs and whether age-related variations exist. The effects of increasing total daily dose of furosemide and concurrent diuretics and vasopressors were assessed as secondary aims.

METHODS

Charts from patients receiving intravenous or oral furosemide for at least 3 consecutive days of therapy between June 1, 2013, and December 31, 2013, were reviewed retrospectively. Daily net fluid balance was used as the objective marker for development of tolerance. Net fluid balance (mL/kg/mg) was defined as the difference in a patient's daily intake and urine output (mL), normalized by weight (kg) and total daily dose of furosemide (mg).

RESULTS

Sixty-one patients, aged 2 days to 20 years (median 3 years), were included in this study. Median daily dose of furosemide was 1.96 mg/kg/day (range, 0-13.7 mg/kg/day). Average net fluid balance for all patients on the first day and last day of therapy was 6.83 and 26.66 mL/kg/mg, respectively (p = 0.011). Linear regression and Spearman's correlation found no significant relationship between age and difference in net fluid balance between the first and last day. Linear mixed-effects model for net fluid balance with day as covariate found that net fluid balance increases over time (p = 0.002).

CONCLUSIONS

Pediatric patients appear to develop tolerance to chronic intermittent furosemide therapy.

Simultaneous determination of metolazone and valsartan in plasma by on-line SPE coupled with liquid chromatography/tandem mass spectrometry

Combination of metolazone (0.5 mg) and valsartan (80 mg) has been verified as a promising therapy treatment for hypertension. In order to facilitate to pharmacokinetic research, it needs a method for the simultaneously determination of metolazone and valsartan in biological samples. However, there are no relative reports so far. In order to facilitate to pharmacokinetic research, an on-line solid phase extraction coupled with liquid chromatography-tandem mass spectrometry method for the simultaneous determination of metolazone and valsartan in beagle dog plasma was developed and validated in this study. An on-line solid phase extraction column Retain PEP Javelin (10 mm × 2.1 mm) was used to remove impurities in plasma samples. The metolazone, valsartan and internal standard (losartan) were separated on a Poroshell 120 SB-C18 column (4.6 mm × 50 mm × 2.7 µm) with a gradient elution procedure. Acidified acetonitrile/water mixture was used as a mobile phase. The selected multiple-reaction monitoring mode in positive ion was performed and the parent to the product transitions m/z 366/259, m/z 436.2/291 and m/z 423.4/207 were used to measure the metolazone, valsartan and losartan. The method was linear over the range of 0.1-100 ng/mL and 1-1000 ng/mL for metolazone and valsartan, respectively. This method was validated in terms of specificity, linearity, sensitivity, precision, accuracy, matrix effect, and stability and then successfully applied to pharmacokinetic studies of the metolazone and valsartan combination tablets in beagle dogs.

Efficacy of sequential nephron blockade with intravenous chlorothiazide to promote diuresis in cardiac intensive care infants

BACKGROUND

Sequential nephron blockade using intravenous chlorothiazide is often used to enhance urine output in patients with inadequate response to loop diuretics. A few data exist to support this practice in critically ill infants.

METHODS

We included 100 consecutive patients <1 year of age who were administered intravenous chlorothiazide while receiving furosemide therapy in the cardiac ICU in our study. The primary end point was change in urine output 24 hours after chlorothiazide administration, and patients were considered to be responders if an increase in urine output of 0.5 ml/kg/hour was documented. Data on demographic, clinical, fluid intake/output, and furosemide and chlorothiazide dosing were collected. Multivariable regression analyses were performed to determine variables significant for increase in urine output after chlorothiazide administration.

RESULTS

The study population was 48% male, with a mean weight of 4.9±1.8 kg, and 69% had undergone previous cardiovascular surgery. Intravenous chlorothiazide was initiated at 89 days (interquartile range 20-127 days) of life at a dose of 4.6±2.7 mg/kg/day (maximum 12 mg/kg/day). Baseline estimated creatinine clearance was 83±42 ml/minute/1.73 m2. Furosemide dose before chlorothiazide administration was 2.8±1.4 mg/kg/day and 3.3±1.5 mg/kg/day after administration. A total of 43% of patients were categorised as responders, and increase in furosemide dose was the only variable significant for increase in urine output on multivariable analysis (p<0.05). No graphical trends were noted for change in urine output and dose of chlorothiazide.

CONCLUSIONS

Sequential nephron blockade with intravenous chlorothiazide was not consistently associated with improved urine output in critically ill infants.

Stability of furosemide and chlorothiazide stored in syringes

PURPOSE

The results of a study to determine the stability of solutions of furosemide and chlorothiazide over 96 hours are reported.

METHODS

Chlorothiazide and furosemide were diluted in 5% dextrose USP to final concentrations of 10 and 1 mg/mL, respectively, and combined. In addition, sample solutions of chlorothiazide in dextrose, furosemide in dextrose, and dextrose alone were prepared for control purposes. The resulting solutions were analyzed immediately after preparation and 24, 48, 72, and 96 hours later using a liquid chromatography-tandem mass spectroscopy (LC-MS/MS) system with an electrospray ionization source. Mixtures and samples were diluted 10,000-fold prior to LC-MS/MS analysis so that concentrations of both drugs would be within the assay's linear range of detection.

RESULTS

LC-MS/MS analysis showed that chlorothiazide typically eluted at 2.6 minutes and furosemide at 4.8 minutes. Each compound was degraded by exposure to strong ultraviolet light in a time-dependent manner. Both unmixed and mixed solutions retained over 90% of the original concentrations of chlorothiazide and furosemide for up to 96 hours. Furosemide and chlorothiazide are commonly used concomitantly to maximize diuresis in pediatric patients; the study findings suggest that solutions of furosemide and chlorothiazide can be combined in the same syringe without loss of stability for up to 96 hours.

CONCLUSION

Solutions of chlorothiazide (10 mg/mL) and furosemide (1 mg/mL) stored either separately or together in polypropylene syringes remained stable for up to 96 hours at room temperature and protected from light.

Pediatric Cardiac Intensive Care Society 2014 Consensus Statement: Pharmacotherapies in Cardiac Critical Care Fluid Management

OBJECTIVE

In this Consensus Statement, we review the etiology and pathophysiology of fluid disturbances in critically ill children with cardiac disease. Clinical tools used to recognize pathologic fluid states are summarized, as are the mechanisms of action of many drugs aimed at optimal fluid management.

DATA SOURCES

The expertise of the authors and a review of the medical literature were used as data sources.

DATA SYNTHESIS

The authors synthesized the data in the literature in order to present clinical tools used to recognize pathologic fluid states. For each drug, the physiologic rationale, mechanism of action, and pharmacokinetics are synthesized, and the evidence in the literature to support the therapy is discussed.

CONCLUSIONS

Fluid management is challenging in critically ill pediatric cardiac patients. A myriad of causes may be contributory, including intrinsic myocardial dysfunction with its associated neuroendocrine response, renal dysfunction with oliguria, and systemic inflammation with resulting endothelial dysfunction. The development of fluid overload has been associated with adverse outcomes, including acute kidney injury, prolonged mechanical ventilation, increased vasoactive support, prolonged hospital length of stay, and mortality. An in-depth understanding of the many factors that influence volume status is necessary to guide optimal management.

Loop diuretics for patients receiving blood transfusions

BACKGROUND

Blood transfusions are associated with significant morbidity and mortality. Prophylactic administration of loop diuretics (furosemide, bumetanide, ethacrynic acid, or torsemide) is common practice, especially among people who are at risk for circulatory overload, pulmonary oedema or both.

OBJECTIVES

This review aimed to determine if the prophylactic administration of loop diuretics (furosemide, bumetanide, ethacrynic acid, or torsemide) provides a therapeutic advantage (that is, a favourable risk benefit ratio) in adults and children who are recipients of any blood product transfusion versus placebo, no treatment, or general fluid restriction measures.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 13 January 2015 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTs assessing a loop diuretic in patients receiving any blood transfusion were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Study authors were contacted for additional information. Results were to be expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) and 95% CI for continuous outcomes. Mean effect sizes were to be calculated using the random-effects models.

MAIN RESULTS

We included four studies that involved 100 participants. Furosemide was the only diuretic investigated in all four studies.None of the included studies assessed the clinically important outcomes noted in our protocol. The studies focused on various markers of respiratory function. An improvement in fraction of inspired oxygen (in favour of furosemide) was noted in one study. An improvement in pulmonary capillary wedge pressure (in favour of furosemide) was noted in two studies.

AUTHORS' CONCLUSIONS

There was insufficient evidence to determine whether premedicating people undergoing blood transfusion with loop diuretics prevents clinically important transfusion-related morbidity. Due to the continued use of prophylactic loop diuretics during transfusions, and because this review highlights the absence of evidence to justify this practice, well-conducted RCTs are needed. Given the high mortality, severe morbidity and increasing incidence of transfusion-associated circulatory overload, determining the therapeutic utility of pre-transfusion loop diuresis is an urgent need.

Furosemide versus ethacrynic acid in pediatric patients undergoing cardiac surgery: a randomized controlled trial

Introduction

Clinical effects of furosemide (F) and ethacrynic acid (EA) continuous infusion on urine output (UO), fluid balance, and renal, cardiac, respiratory, and metabolic function were compared in infants undergoing surgery for congenital heart diseases.

Methods

A prospective randomized double-blinded study was conducted. Patients received 0.2 mg/kg/h (up to 0.8 mg/kg/h) of either F or EA.

Results

In total, 38 patients were enrolled in the F group, and 36, in the EA group. No adverse reactions were recorded. UO at postoperative day (POD) 0 was significantly higher in the EA group, 6.9 (3.3) ml/kg/h, compared with the F group, 4.6 (2.3) ml/kg/h (P = 0.002) but tended to be similar in the two groups thereafter. Mean administered F dose was 0.33 (0.19) mg/kg/h compared with 0.22 (0.13) mg/kg/h of EA (P < 0.0001). Fluid balance was significantly more negative in the EA group at postoperative day 0: −43 (54) ml/kg/h versus −17 (32) ml/kg/h in the F group (P = 0.01). Serum creatinine, cystatin C and neutrophil gelatinase-associated lipocalin levels and incidence of acute kidney injury did not show significant differences between groups. Metabolic alkalosis occurred frequently (about 70% of cases) in both groups, but mean bicarbonate level was higher in the EA group: 27.8 (1.5) M in the F group versus 29.1 (2) mM in the EA group (P = 0.006). Mean cardiac index (CI) values were 2.6 (0.1) L/min/m² in the F group compared with 2.98 (0.09) L/min/m² in the EA group (P = 0.0081). Length of mechanical ventilation was shorter in the EA group, 5.5 (8.8) days compared with the F group, 6.7 (5.9) (P = 0.06). Length of Pediatric Cardiac Intensive Care Unit (PCICU) admission was shorter in the EA group: 14 (19) days compared with 16 (15) in the F group (P = 0.046).

Conclusions

In cardiac surgery infants, EA produced more UO compared with F on POD0. Generally, a smaller EA dose is required to achieve similar UO than F. EA and F were safe in terms of renal function, but EA caused a more-intense metabolic alkalosis. EA patients achieved better CI, and shorter mechanical ventilation and PCICU admission time.

Trial registration

Clinicaltrials.gov NCT01628731. Registered 24 June 2012.

Co-administration of furosemide with albumin for overcoming diuretic resistance in patients with hypoalbuminemia: a meta-analysis

PURPOSE

To systematically review clinical studies of co-administration of albumin and loop diuretics in hypoalbuminemic patients as a strategy to overcome diuretic resistance.

MATERIALS AND METHODS

Systematic search of electronic databases up to October 2012. We included randomized clinical trials of adults with hypoalbuminemia, comparing co-administration of loop diuretics and albumin versus loop diuretics alone. Quantitative data were synthesized with meta-analytic techniques for clinical, surrogate (urinary volume and urinary sodium excretion) and intermediate (pharmacokinetic and hemodynamic parameters) outcomes.

RESULTS

Ten studies were included, of which 8 trials with crossover design were synthesized with meta-analysis. A statistically significant increase in the amount of urine volume (increment of 231 mL [95% confidence interval 135.5-326.5]) and sodium excreted (15.9 mEq [4.9-26.8]) at 8 hours were found in favor of co-administration of albumin and furosemide. These differences were no longer statistically significant at 24 hours. Meta-analyses for intermediate outcomes (ie, furosemide excretion, distribution volume etc.) did not reveal statistically significant differences.

CONCLUSIONS

Synthesis of a heterogeneous body of evidence shows transient effects of modest clinical significance for co-administration of albumin with furosemide in hypoalbuminemic patients. Pragmatic, large-scale randomized studies are needed to delineate the role of this strategy.

Clinical pharmacology of furosemide in neonates: a review

Furosemide is the diuretic most used in newborn infants. It blocks the Na⁺-K⁺-2Cl⁻ symporter in the thick ascending limb of the loop of Henle increasing urinary excretion of Na⁺ and Cl⁻. This article aimed to review the published data on the clinical pharmacology of furosemide in neonates to provide a critical, comprehensive, authoritative and, updated survey on the metabolism, pharmacokinetics, pharmacodynamics and side-effects of furosemide in neonates. The bibliographic search was performed using PubMed and EMBASE databases as search engines; January 2013 was the cutoff point. Furosemide half-life (t_1/2) is 6 to 20-fold longer, clearance (Cl) is 1.2 to 14-fold smaller and volume of distribution (Vd) is 1.3 to 6-fold larger than the adult values. t_1/2 shortens and Cl increases as the neonatal maturation proceeds. Continuous intravenous infusion of furosemide yields more controlled diuresis than the intermittent intravenous infusion. Furosemide may be administered by inhalation to infants with chronic lung disease to improve pulmonary mechanics. Furosemide stimulates prostaglandin E2 synthesis, a potent dilator of the patent ductus arteriosus, and the administration of furosemide to any preterm infants should be carefully weighed against the risk of precipitation of a symptomatic patent ductus arteriosus. Infants with low birthweight treated with chronic furosemide are at risk for the development of intra-renal calcifications.

Clinical pharmacology of the loop diuretics furosemide and bumetanide in neonates and infants

The loop diuretics furosemide and bumetanide are used widely for the management of fluid overload in both acute and chronic disease states. To date, most pharmacokinetic studies in neonates have been conducted with furosemide and little is known about bumetanide. The aim of this article was to review the published data on the pharmacology of furosemide and bumetanide in neonates and infants in order to provide a critical analysis of the literature, and a useful tool for physicians. The bibliographic search was performed electronically using PubMed and EMBASE databases as search engines and March 2011 was the cutoff point. The half-life (t(½)) of both furosemide and bumetanide is considerably longer in neonates than in adults and consequently the clearance (CL) of these drugs is reduced at birth. In healthy volunteers, plasma t(½) of furosemide ranges from 33 to 100 minutes, whereas in neonates it ranges from 8 to 27 hours. The volume of distribution (V(d)) of furosemide undergoes little variation during neonate maturation. The dose of furosemide, administered by intermittent intravenous infusion, is 1 mg/kg and may increase to a maximum of 2 mg/kg every 24 hours in premature infants and every 12 hours in full-term infants. Comparison of continuous infusion versus intermittent infusion of furosemide showed that the diuresis is more controlled with fewer hemodynamic and electrolytic variations during continuous infusion. The appropriate infusion rate of furosemide ranges from 0.1 to 0.2 mg/kg/h and when the diuresis is <1 mL/kg/h the infusion rate may be increased to 0.4 mg/kg/h. Treatment with theophylline before administration of furosemide results in a significant increase of urine flow rate. Bumetanide is more potent than furosemide and its dose after intermittent intravenous infusion ranges from 0.005 to 0.1 mg/kg every 24 hours. The t(½) of bumetanide in neonates ranges from 1.74 to 7.0 hours. Up to now, no data are available on the continuous infusion of bumetanide. Extracorporeal membrane oxygenation (ECMO) is used for a variety of indications including sepsis, persistent pulmonary hypertension, meconium aspiration syndrome, cardiac defects and congenital diaphragmatic hernia. There are two studies of furosemide in neonates undergoing ECMO and only one on the pharmacokinetics of bumetanide under ECMO. When ECMO was conducted for 72 hours, the total amount of furosemide administered was 7.0 mg/kg, and the urine production in the 3 days of treatment was about 6 mL/kg/h, which is the target value. The t(½) of bumetanide in neonates during ECMO was extremely variable. CL, t(½), and V(d) were 0.63 mL/min/kg, 13.2 hours, and 0.45 L/kg, respectively. Furosemide may be administered by inhalation and inhibits the bronco-constrictive effect of exercise, cold air ventilation and antigen challenge. However, inhaled furosemide is not active in infants with viral bronchiolitis and its effect on broncho-pulmonary dysplasia is still uncertain. Furosemide does not significantly increase the risk of failure of patent ductus arteriosus closure when indomethacin or ibuprofen have been co-administered. Infants with low birth weight treated long-term with furosemide are at risk for the development of intra-renal calcification. Furosemide therapy above 10 mg/kg bodyweight cumulative dose had a 48-fold increased risk of nephrocalcinosis. The use of furosemide in combination with indomethacin increased the incidence of acute renal failure. The maturation of the kidney governs the pharmacokinetics of furosemide and bumetanide in the infant. CL and t(½) are influenced by development, and this must be taken into consideration when planning a dosage regimen with these drugs.

The use of bumetanide for oliguric acute renal failure in preterm infants

OBJECTIVE

To determine the effects of bumetanide in preterm infants with oliguric acute renal failure (OARF).

STUDY DESIGN

Retrospective data review and multivariate analysis of urine output and serum creatinine, blood urea nitrogen, Na, K, Cl, and Ca levels before, during, and after bumetanide therapy in preterm infants with OARF whose conditions did not respond to furosemide therapy.

RESULTS

A total of 35 infants received bumetanide for OARF after an initial trial of furosemide. Their birth weight, gestational age at birth, and postconceptional age at OARF were 811 ± 326 g, 26 ± 2.75 wks, and 29.2 ± 2.7 wks, respectively. Twenty-nine of the 35 infants (83%) responded to bumetanide. Seventeen of the 35 infants subsequently died in the hospital due to multiorgan dysfunction. For the survivors (n = 18) and 11 of 17 of nonsurvivors, urine output increased from 0.6 ± 0.6 mL/kg/hr to 3.0 ± 2.1 mL/kg/hr during bumetanide therapy (p < .0005). Serum creatinine levels increased from 2.13 ± 0.83 mg/dL to 2.3 ± 0.92 mg/dL (p = .04) during bumetanide treatment, whereas blood urea nitrogen levels decreased after bumetanide therapy from 38 ± 19 mg/dL to 31.67 ± 21.6 mg/dL (p = .049). No significant changes were noted in serum sodium, chloride, or calcium concentration.

CONCLUSIONS

Bumetanide therapy significantly increased urine output within 24-48 hrs, but its use was associated with a transient increase in serum creatinine level. Bumetanide can be used in preterm infants to reverse oliguria when therapy with furosemide fails. Prospective, randomized, controlled trials with long-term follow-up in preterm infants are necessary to establish the usefulness of bumetanide for OARF.

Bumetanide inhibits rapid kindling in neonatal rats

PURPOSE

To examine the effects of bumetanide, a selective blocker of Na+-K+-2Cl- cotransporter (NKCC1), on hippocampal excitability and rapid kindling in immature rats.

METHODS

Studies were performed in Wistar rats of three ages: postnatal day 11 (P11, neonatal), P14 (postneonatal), and P21 (preadolescent). Bumetanide (0.2, 0.5, 2.5 mg/kg) was given intraperitoneally 20 min prior to the beginning of the studies. Hippocampal excitability was examined by measuring threshold and duration of afterdischarge, which had been elicited by electrical stimulation of ventral hippocampus. Kindling procedure consisted of 80 electrical stimulations of ventral hippocampus, delivered every 5 min.

RESULTS

At P11, bumetanide (0.5 mg/kg) increased the baseline hippocampal afterdischarge threshold and shortened the afterdischarge duration. Bumetanide delayed the occurrence, and reduced the number of full motor seizures during kindling, and prevented the development of kindling-induced enhanced seizure susceptibility in a majority of animals. At P14, bumetanide (0.5 mg/kg) induced no significant antiepileptic effects, although suppression of hippocampal excitability and inhibition of kindling were observed in a subset of animals. At P21, bumetanide (0.2; 2.5 mg/kg) exerted no effects on hippocampal excitability and kindling progression.

DISCUSSION

The obtained results provide further evidence that bumetanide may be beneficial for treating neonatal seizures, and that NKCC1 represents a potential target for antiepileptic interventions in the immature brain.

An exploratory study with an adaptive continuous intravenous furosemide regimen in neonates treated with extracorporeal membrane oxygenation

INTRODUCTION

The objective of the present study was to explore a continuous intravenous furosemide regimen that adapts to urine output in neonates treated with extracorporeal membrane oxygenation (ECMO).

METHODS

Seven neonates admitted to a paediatric surgical intensive care unit for ECMO therapy were treated with a furosemide regimen consisting of a loading bolus (1-2 mg/kg) followed by a continuous infusion at 0.2 mg/kg per hour, which was adjusted according to the target urine production of 6 ml/kg per hour. Therapeutic drug monitoring for furosemide concentrations in blood was performed.

RESULTS

The mean +/- standard deviation furosemide dose was 0.17 +/- 0.06 mg/kg per hour, 0.08 +/- 0.04 mg/kg per hour and 0.12 +/- 0.07 mg/kg per hour, respectively, on the first day, second day and third day of the study. The median (range of the urine production of the study subjects) urine production over the consecutive study days was 6.8 (0.8-8.4) mg/kg per hour, 6.0 (4.7-8.9) mg/kg per hour and 5.4 (3.4-10.1) ml/kg per hour. The target urine production was reached after a median time of 7 (3-37) hours. The regimen was haemodynamically well tolerated and the median furosemide serum concentration was 3.1 (0.4-12.9) mug/ml, well below the toxic level.

CONCLUSION

The evaluated furosemide infusion appears an effective means to reduce volume overload in neonates treated with ECMO. The data of this preliminary study suggest that the starting dose of furosemide was too high, however, because the urine output was excessive and required frequent adaptations. The results of this study therefore indicate that a novel pharmacokinetic/pharmacodynamic model needs to be developed for neonates treated with ECMO.

Absence of tolerance and toxicity to high-dose continuous intravenous furosemide in haemodynamically unstable infants after cardiac surgery

AIM

To evaluate a high-dose continuous furosemide regimen in infants after cardiac surgery.

METHODS

Fifteen haemodynamically unstable infants with volume overload admitted to a paediatric intensive care unit were treated with an aggressive furosemide regimen consisting of a loading bolus (1-2 mg kg(-1)) followed by a continuous infusion at 0.2 mg kg(-1) h(-1) which was adjusted according to a target urine output of 4 ml kg(-1) h(-1). Frequent sampling for furosemide concentrations in blood and urine was done for 3 days with simultaneous assessment of sodium excretion and urine output.

RESULTS

The mean furosemide dose was 0.22 (+/- 0.06), 0.25 (+/- 0.10) and 0.22 (+/- 0.11) mg kg(-1) h(-1) on the first, second and third day, respectively. Median urine production was 3.0 (0.6-5.3), 4.2 (1.7-6.6) and 3.9 (2.0-8.5) ml kg(-1) h(-1), respectively, on the first, second and third day of the study. The target urine production was reached at a median time of 24 (6-60) h and this was maintained during the study period. The regimen did not result in toxic serum concentrations and was haemodynamically well tolerated.

CONCLUSION

High-dose continuous furosemide infusion for 72 h in haemodynamically unstable infants after cardiac surgery appears to be a safe and effective treatment for volume overload. Development of tolerance against the effects of furosemide and ototoxic furosemide concentrations were not observed.

Evaluation of furosemide regimens in neonates treated with extracorporeal membrane oxygenation

Introduction

Loop diuretics are the most frequently used diuretics in patients treated with extracorporeal membrane oxygenation (ECMO). In patients after cardiopulmonary bypass (CPB) surgery, the use of continuous furosemide infusion is increasingly documented. Because ECMO and CPB are 'comparable' procedures, continuous furosemide infusion is used in newborns on ECMO. We report on the use of continuous intravenous furosemide in neonates treated with ECMO.

Methods

This was a retrospective observational study in neonates treated with continuous intravenous furosemide during ECMO.

Results

Thirty-one patients were included in the study. A median of 25 (9–149) hours after the start of ECMO, continuous furosemide therapy was started at a median rate of 0.08 (0.02–0.17) mg/kg per hour. The continuous furosemide dose was not changed in the individual patient. Seven patients received a furosemide bolus prior to, and five patients received additional loop diuretics during, the continuous infusion. Urine production before continuous furosemide therapy was not significantly different between patients who received a furosemide bolus prior to the infusion and those who did not receive this bolus (P = 0.2879). Although a positive effect of the 'loading' bolus was observed in urine output in the first 24 hours, there was no statistically significant difference in urine output (P = 0.0961) or in time (P = 0.1976) to reach a urine output of 6 ml/kg per hour between patients. After 24 hours, urine production remained a median of 6.2 ml/kg per hour irrespective of furosemide boluses. The forced diuresis was well tolerated as illustrated by stable haemodynamic parameters and a decrease in ECMO flow and vasopressor score over the observation period.

Conclusion

This is the first report on continuous intravenous furosemide therapy in newborns treated with ECMO. The furosemide regimens used in this study varied widely in continuous and intermittent doses. However, all regimens achieved adequate urine output. An advantage of continuous, over intermittent, intravenous furosemide could not be documented. Furosemide dosing regimens should be developed for neonates treated with ECMO. In addition, therapeutic drug-monitoring studies are required to prevent furosemide toxicity because so far no data are available on serum furosemide levels in neonates treated with ECMO.

Diuretics in pediatrics : current knowledge and future prospects

This review summarizes current knowledge on the pharmacology, pharmacokinetics, pharmacodynamics, and clinical application of the most commonly used diuretics in children. Diuretics are frequently prescribed drugs in children. Their main indication is to reduce fluid overload in acute and chronic disease states such as congestive heart failure and renal failure. As with most drugs used in children, optimal dosing schedules are largely unknown and empirical. This is undesirable as it can potentially result in either under- or over-treatment with the possibility of unwanted effects. The pharmacokinetics of diuretics vary in the different pediatric age groups as well as in different disease states. To exert their action, all diuretics, except spironolactone, have to reach the tubular lumen by glomerular filtration and/or proximal tubular secretion. Therefore, renal maturation and function influence drug delivery and consequently pharmacodynamics. Currently advised doses for diuretics are largely based on adult pharmacokinetic and pharmacodynamic studies. Therefore, additional pharmacokinetic and pharmacodynamic studies for the different pediatric age groups are necessary to develop dosing regimens based on pharmacokinetic and pharmacodynamic models for all routes of administration.

Short-term medical management of hydrocephalus

Hydrocephalus is an excess accumulation of cerebrospinal fluid in or around the brain that can be produced by a broad spectrum of disorders. It can develop at any age and its incidence is increasing, both in infants and adults. Although the standard treatment of hydrocephalus is cerebrospinal fluid shunting, there are certain circumstances in which medical treatment, alone or in combination with shunting, has been suggested as an alternative. This review aims to present and discuss the indications for pharmacological treatment in the medical management of hydrocephalus, and the drugs most frequently used. Carbonic anhydrase inhibitors, loop diuretic agents, osmotic agents and fibrinolytic therapy are discussed. The most suitable drug seems to be acetazolamide, alone or in combination with furosemide. At present, osmotic agents are no longer used in the treatment of hydrocephalus. Fibrinolytic therapy administered directly into the ventricular system may not avoid the need for shunt placement, but may help in the management of hydrocephalus by preventing or reducing the rate of catheter obstruction and accelerating clot resolution.

Oral urea for the treatment of chronic syndrome of inappropriate antidiuresis in children

We report the successful use of oral urea in the management of children with chronic syndrome of inappropriate antidiuretic hormone secretion (SIAD). We performed a retrospective review of four children with chronic SIAD. After initial attempts at management with fluid restriction, each was started on a 30% to 50% oral urea solution, and the dose was titrated until normal serum sodium was achieved. Fluid intake was liberalized after serum sodium normalization. All four children normalized their serum sodium. No side effects or toxicities were experienced. Oral urea is a safe, effective treatment for chronic SIAD in children.

Furosemide: progress in understanding its diuretic, anti-inflammatory, and bronchodilating mechanism of action, and use in the treatment of respiratory tract diseases

Accumulated experimental and clinical data suggest that adrenocorticosteroids and/or endogenous ouabain-like substances may play an important role in the mechanism of furosemide diuretic action. It was reported that the drug is highly bound in the adrenals, lungs, kidney, spleen, and liver. In patients with liver cirrhosis, furosemide exerted a markedly decreased natriuretic effect compared with normal subjects, and the plasma levels of circulating endothelin and atrial natriuretic factor (ANF) were significantly elevated. In neonates, after administration of furosemide, the urinary excretion of endothelin-1 and aldosterone increased markedly, and it is known that endothelin may release ANF and aldosterone in a dose-dependent manner. Furosemide was used to stimulate zona glomerulosa, whereas ANF decreased the production of steroids in zona glomerulosa and fasciculata cell culture owing to stimulation by various factors. Because the concomitant use of ANF and furosemide appeared to be diuretically effective in newborns after cardiac surgery, one may suggest that furosemide competes with ANF for its effects on the adrenals. Furosemide administered by inhalation exerted a protective effect on allergic and perennial nonallergic rhinitis and was effective in preventing the postsurgical recurrence of nasal polyposis. The drug can also be used as an antiasthmatic agent. In preterm ventilator-dependent infants with chronic lung disease, aerosolized furosemide improved pulmonary function with no marked effect on diuresis. In adults and children with asthma, furosemide exerted a protective effect against bronchoconstriction induced by several indirect stimuli similar to that of disodium cromoglycate or nedocromil. Aerosolized furosemide had a preventive effect also on bronchoconstriction induced by inhaled lysine acetylsalicylate in patients with aspirin-sensitive asthma. In high-dose beclomethasone-dependent asthma, inhaled lysine acetylsalicylate and furosemide exerted a mutually potentiating antiasthmatic activity, allowing considerable sparing of the inhaled steroid. It is proposed that this effect may be explained by the corticosteroid-sparing action of lysine released from the lysine acetylsalicylate molecule because similar beneficial effects were also obtained after the concomitant use of epsilon-aminocaproic acid (whose chemical structure is almost the same as that of lysine) and prednisone. Furosemide exhibited an anti-inflammatory effect through inhibition of production and release of cytokines interleukin (IL)-6, IL-8, and tumor necrosis factor-alpha from peripheral mononuclear cells, which may have a beneficial effect on local inflamed tissue imbalance in the ratio of different cytokines, thus improving the sensitivity of target cells to endogenous glucocorticosteroids.

Serial plasma concentrations of atrial natriuretic peptide, plasma renin activity, aldosterone, and antidiuretic hormone in neonates on extracorporeal membrane oxygenation

To obtain information on water and salt regulating hormones and volume homeostasis during neonatal extracorporeal membrane oxygenation (ECMO), serial determinations of atrial natriuretic peptide (ANP), plasma renin activity (PRA), aldosterone (Aldo), antidiuretic hormone (ADH), colloid-osmotic pressure (COP), osmolality (Osmol), and central venous pressure (CVP) before, during, and after neonatal ECMO in 10 neonates with meconium aspiration syndrome (MAS) were carried out. Mean gestational ages and birth weights were 41(+3) weeks (39(+6) - 42(+4)) and 4,063 gm (3,500-4700), respectively; mean age at start and duration of ECMO 29.3 (14-69) and 152.6 hr (92-267), respectively. Plasma ANP (mean +/- SD) was 67.8+/-69.1 pmol/L before, decreased to 33.3+/-22.1 (not significant) pmol/L during, and significantly increased to 274.6+/-131.8 pmol/L after ECMO (p < 0.05). ANP correlated positively with CVP (r = 0.63; p < 0.001). Pre-ECMO PRA, Aldo, and ADH were comparable to those described earlier in normal neonates, decreased during (p < 0.001 for Aldo; p < 0.05 for PRA and ADH) and either remained elevated (PRA, p < 0.001; Aldo, p < 0.05) or decreased (ADH) after ECMO. COP and Osmol remained unchanged. Neonatal ECMO for MAS is characterized by circulatory and osmotic equilibrium. It is suggested that circulating volume contracts during and expands after neonatal ECMO for MAS.

Clinical pharmacology of furosemide in children: a supplement

Furosemide is one of the most effective and least toxic diuretics used in pediatric practice. Experimental and clinical data suggest that adrenocorticosteroids and/or endogenous ouabain-like substances may play an important role in its diuretic effect. Also, the drug appears to have anti-inflammatory properties. In children with different diseases who received orally or intravenously 1 to 2 mg/kg doses of furosemide, a statistically significant positive linear relationship was found between the drug urinary excretion rate and the urine flow rate, but log dose-response curves to the drug were found to vary depending on the disease and the route of the drug administration. No sigmoid-shaped log dose-response curve (ie, one approaching a zero response at very low furosemide urinary excretion rates and a maximum response at very high excretion rates) was attained, which may suggest that the capacity of the kidney tubules to respond diuretically to the aforementioned doses of furosemide was not exceeded in these patients. However, in infants with different diseases and reasonably normal renal function who required administration of this diuretic, a very steep log dose-response curve to a 1 mg/kg intravenous dose of furosemide was found, which may suggest that higher doses may not result in a significant increase in diuretic response. The lowest mean furosemide urinary excretion rate and its concentration in urine associated with a significant diuresis were found to be 0.58 +/- 0.33 microg/kg/min and 24.2 +/- 10.5 microg/ml, respectively. Also, a significant correlation was found between the amount (in milligrams) of furosemide excreted in the urine during the first 6 hours after administration and the urine volume collected during that time. Patients with cystic fibrosis appeared to have a markedly more pronounced diuretic response to the average oral dose of 0.835 +/- 0.18 mg/kg than that reported in control children given 2 mg/kg. In children with acute renal failure caused by acute gastroenterocolitis or glomerulonephritis, a broad relationship was observed between a single intravenous dose and diuretic response after administration of furosemide (1.2 to 30.8 mg/kg). It was suggested that the total daily dose of the drug should not exceed 100 mg in these patients. Furosemide was found to be effective in management of bronchoconstriction accompanying chronic lung disease and narrowing of the upper respiratory airways; in hydrocephalus in infancy to avoid cerebrospinal fluid shunts; in some diagnostic procedures, such as an assessment of fetal and neonatal hydronephrosis; and in evaluation of different types of renal tubular acidosis. Among side effects accompanying clinical use of this drug were cholelithiasis in premature infants receiving total parenteral nutrition concomitantly with the diuretic; secondary hyperparathyroidism and bone disease in infants obtaining long-term furosemide treatment; and drug-induced fever.

Diuretic therapy of heart failure in infants and children

Diuretics are the mainstay of traditional therapy for congestive heart failure. The syndrome of heart failure is now understood to involve complex interactions of neurohumoral substances released in response to poor cardiac function. Developmental changes during infancy and childhood will affect both the activation of systemic neurohumoral responses and the pharmacokinetic and pharmacodynamic actions of diuretics. Few human studies directly evaluate the efficacy of diuretic therapy in heart failure in adults. The pharmacodevelopmental aspects of diuretic therapy in infants and children are also incompletely studied. This review will describe the kidney's role in the pathogenesis of sodium and water retention in heart failure and the developmental changes in the kidney related to fluid retention. Known principles of diuretic therapy in congestive heart failure will be described. All these factors can then be used by the reader to evaluate the role of diuretic therapy in the complex syndrome of heart failure in infants and children.

Failure of the loop diuretic torasemide to improve renal function of hypoxemic vasomotor nephropathy in the newborn rabbit

The use of diuretic therapy in vasomotor nephropathy is a controversial topic. It is generally agreed that diuretics in this situation enhance urinary output, reduce the degree of volume expansion, and improve cardiac and especially the compromised lung function. It is less clear whether diuretic therapy improves kidney function. The present study evaluates the effects of intravenous torasemide on renal function in 25 anesthetized ventilated hypoxemic newborn New Zealand White rabbits with vasomotor nephropathy. This well-established animal model mimics the renal physiology of the human newborn and, in particular, that of the premature infant. Three groups of hypoxemic rabbits were studied. The animals of group 1 (n = 8) received no diuretic therapy (hypoxemic control), and those of group 2 (n = 9) were given a single intravenous dose of torasemide (1 mg/kg) in a curative fashion 2 h after hypoxemia was induced. In the third group of animals (n = 8), torasemide was given preventively; a bolus intravenous dose of torasemide (0.2 mg/kg) was given before the induction of hypoxemia and sustained by the addition of 0.2 mg x kg(-1) x h(-1) of the drug to the continuous intravenous infusion given throughout the entire 3-h hypoxemic period. Hypoxemia alone (group 1) caused acute renal insufficiency with a significant fall in mean arterial blood pressure, GFR, and renal blood flow; the renal vascular resistance increased, and the filtration fraction was unchanged. The curative dose of torasemide (group 2) induced a significant diuresis and natriuresis with minimal augmentation of urinary potassium excretion, converting mildly oliguric to nonoliguric acute renal insufficiency. In this group of animals, torasemide did not improve the glomerular dysfunction. The preventive dose of torasemide (group 3) even somewhat worsened the already impaired renal functions without further increasing the diuretic effect of the drug. We conclude that in hypoxemic newborn animals with renal dysfunction, torasemide is an effective potassium-sparing diuretic that unfortunately does not improve renal blood flow and GFR. The failure of torasemide to attenuate the glomerular dysfunction of hypoxemic vasomotor nephropathy in the newborn rabbit is disturbing. These data certainly caution against the overzealous use of loop diuretics in hypoxemic oliguric neonates.