Intravenous Administration Of Magnesium Sulfate Research Articles

Pharmacological treatment of acquired QT prolongation and torsades de pointes.

Torsades de pointes (TdP) is a characteristic polymorphic ventricular arrhythmia associated with delayed ventricular repolarization as evidenced on the surface electrocardiogram by QT interval prolongation. It typically occurs in self-limiting bursts, causing dizziness and syncope, but may occasionally progress to ventricular fibrillation and sudden death. Acquired long QT syndromes are mainly caused by cardiac disease, electrolyte abnormalities or exposure to drugs that block rectifying potassium channels, especially IKr. Management of TdP or marked QT prolongation includes removal or correction of precipitants, including discontinuation of culprit drugs and institution of cardiac monitoring. Electrolyte abnormalities and hypoxia should be corrected, with potassium concentrations maintained in the high normal range. Immediate treatment of TdP is by intravenous administration of magnesium sulphate, terminating prolonged episodes using electrical cardioversion. In refractory cases of recurrent TdP, the arrhythmia can be suppressed by increasing the underlying heart rate using isoproterenol (isoprenaline) or transvenous pacing. Other interventions are rarely needed, but there are case reports of successful use of lidocaine or phenytoin. Anti-arrhythmic drugs that prolong ventricular repolarization should be avoided. Some episodes of TdP could be avoided by careful prescribing of QT prolonging drugs, including an individualized assessment of risks and benefits before use, performing baseline and periodic electrocardiograms and measurement of electrolytes, especially during acute illnesses, using the lowest effective dose for the shortest possible time and avoiding potential drug interactions. These steps are particularly important in those with underlying repolarization abnormalities and those who have previously experienced drug-induced TdP.

Current insights in brain protection for the sick newborn infant

This paper presents an overview of the modern antenatal and postnatal strategies in brain protection for both preterm and term born infants. It is known, that the two most common causes of neonatal brain injury are prematurity and hypoxic-ischemic encephalopathy (HIE) in the term born infant. Approximately one in nine babies is born before term. Nowadays these preterm born infants more often survive the neonatal period due to developments in treatment options in the last decades. They are however at a high risk for developing brain damage and neurodevelopmental impairment later in life. Approximately 40 % of survivors develop long-term intellectual or physical impairment, including cerebral palsy (CP). Term born infants born after perinatal asphyxia may also survive with a variety of neurocognitive disorders due to brain damage as a result from the hypoxic ischemic encephalopathy (HIE). Untreated, the sequelae of moderate to severe HIE includes a 60 to 65 % risk of mental retardation, CP, hydrocephalus, seizures, or death. The main goal in neonatal care for these surviving but vulnerable infants is to preserve brain function and prevent further brain damage, in order to improve neurocognitive outcome and the subsequent quality of life. In preterm brain protection antenatal strategies besides educating and supporting pregnant women regarding life style and healthy food intake, centralization of care for extreme preterm born infants, fetal monitoring in high risk pregnancies, administration of antenatal steroids for lung maturity, the use of intravenous magnesium sulfate administration to mothers just before preterm delivery are of great importance. In the postnatal strategies setting optimal oxygen saturation, the avoidance of prolonged artificial mechanical ventilation, hypoglycemia, hypocapnia electrolytic imbalances, hyperbilirubinemia, blood pressure shifts, stress and pain, inflammation, necrotizing enterocolitis as well as adequate feeding strongly predict neurocognitive outcome. In the term asphyxiated infants the brain experiences a cascade of problems occurring after energy failure which in fact are the basis of neuroprotective strategies. These strategies consist of anti-oxidative, anti-inflammatory, anti-excitatoxic and anti-apoptotic agents, and in the future possibly neurogenetic approaches, including stem cell therapy. In antenatal strategies prevention of asphyxia starts at promoting a healthy pregnancy and of an early recognition of fetal, placental or perinatal risk factors for hypoxia. Recent experimental trials have shown a possible beneficial effect of antenatal administration of the anti-oxidative agent allopurinol in a HIE. In postnatal strategies two methods to achieve therapeutic hypothermia were evaluated in newborn infants with HIE: whole body cooling and selective head cooling with mild systemic hypothermia with the conclusion: hypothermia should be instituted in term infants with moderate-to-severe hypoxic ischemic encephalopathy if identified before six hours of age. Monitoring of brain activity by means of amplitude integrated electroencephalography to identify infants with HIE is promising. Potential agents with either anti-oxidative, anti-inflammatory, anti-excitatoxic or anti-apoptotic capacities are currently being investigated in various phases of research.

Magnesium Sulfate in Exacerbations of COPD in Patients Admitted to Internal Medicine Ward.

The purpose of this study was to examine the effect of intravenous magnesium sulfate on patients with COPD exacerbation requiring hospitalization. In this randomized clinical trial 30 patients with COPD exacerbation were studied. Patients were randomly assigned to group A (case) who concurrent with standard therapy received 2 g magnesium sulfate in normal saline infused in 20 minutes on days one to three and group B (control) who received standard medications and placebo. PEFR and FEV1 were measured by before, 45 minutes and third day of entering the study. Vital signs HR, BP, RR, temperature and SpO2 were monitored during hospitalization. 21 males and 9 females patients with mean age of 68 ± 9 years, case 67 ± 10 and control 70 ± 8 were studied (15 patients in each arm of study). The mean pretreatment FEV1 was 26% ± 12, and 35% ± 18 in case and control groups respectively (P=0.137). FEV1 after 45 minutes in case group was 27% ± 9 and control group 36% ± 20 (p=0.122). FEV1 after 3 days of study was 32% ± 17 in case and 41% ± 22 in control groups (P=0.205). The mean pretreatment PEFR was 126 ± 76 l/min in case and 142 ± 62 l/min in control groups (P=0.46). Changes in PEFR were not significant 45 min (p=0.540) and 3 days (p=0.733) of the administration of intravenous magnesium sulfate. Duration of hospital stay between the two groups did not show any significant difference. This study showed that administration of intravenous magnesium sulfate in hospitalized patients with COPD exacerbation neither revealed any significant bronchodilating effect nor reduced duration of hospital stay.

Acute Effect of Intravenous Administration of Magnesium Sulfate on Serum Levels of Interleukin-6 and Tumor Necrosis Factor-α in Patients Undergoing Elective Coronary Bypass Graft With Cardiopulmonary Bypass.

Background:Cardiovascular problems are among the most common health issues. A considerable number of cardiac patients undergo cardiac surgery, and coronary artery disease patients constitute about two-thirds of all these surgeries. The application of cardiopulmonary bypass (CBP) usually results in some untoward effects.Objectives:Studies have suggested magnesium sulfate (MgSO4) as an anti-inflammatory agent in a coronary artery bypass graft (CABG). This study aimed to assess the effect of an IV MgSO4 infusion during elective CABG (with CBP) on the blood levels of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α).Materials and Methods:During a 12 month period, after review board approval and based on inclusion and exclusion criteria, 90 patients were selected and entered randomly into one of the two study groups (MgSO4 or placebo). Anesthesia, surgery and CBP were performed in exactly the same way, except for the use of MgSO4 or a placebo. Both preoperative and postoperative plasma levels of IL-6 and TNF-α were checked and compared between the two groups using an ELISA.Results:There was no difference found between the two groups with regard to; gender, basic variables, Ejection Fraction (EF), CBP time and aortic cross-clamp time. The preoperative levels of IL-6 and TNF-α were not different; however, their postoperative levels were significantly higher in the placebo group (P value = 0.01 for IL-6 and 0.005 for TNF-α).Conclusions:This study showed that MgSO4 infusion could suppress part of the inflammatory response after CABG with CBP. This was demonstrated by decreased levels of interleukin-6 and TNF-α in postoperative serum levels in elective CABG with CBP.

Use of intravenous magnesium sulfate for the treatment of an acute asthma exacerbation in pediatric patients.

The standard of care for treatment of an asthma exacerbation includes oxygen, inhaled short-acting bronchodilators, and systemic corticosteroids; adjunctive therapies, such as intravenous magnesium sulfate, can be used for patients who are having life-threatening exacerbations. The purpose of this study was to analyze the prescribing patterns as well as the safety of intravenous magnesium sulfate for the treatment of acute asthma exacerbations in pediatric patients across multiple hospitals in New Jersey. This retrospective chart review was conducted at 4 medical centers in New Jersey on patients who presented to the emergency department between January 1, 2010, and December 31, 2010. Fifty-three patients were included in the study. In the emergency department, 98% of patients received inhaled albuterol plus ipratropium and 85% received systemic corticosteroids before intravenous magnesium sulfate administration. The median dose of magnesium sulfate was 40 mg/kg with a median time of administration of 20 minutes. One patient experienced hypotension that was thought to be related to magnesium sulfate administration. This study demonstrates that weight-based dosage, as well as time of administration of magnesium sulfate for pediatric patients with an acute asthma exacerbation, varies across different institutions in New Jersey. Magnesium sulfate use was safe in this patient population.

症例 硫酸マグネシウムが有効であった薬剤起因性torsadede pointes(Tdp)の2例

症例 硫酸マグネシウムが有効であった薬剤起因性torsadede pointes(Tdp)の2例

An unusual cause of rapid atrial fibrillation

A 75-yr-old man who presented with stenotic lower-third esophageal cancer was anesthetized for iterative palliative endoscopic dilatation. In the operating room, a case of welltolerated new onset rapid atrial fibrillation (AF) (170 beats min) was diagnosed. This diagnosis prompted us to postpone the procedure. In the morning, an electrocardiogram revealed the absence of cardiac rhythm abnormalities; however, fluid expansion and intravenous administration of magnesium sulfate 1.5 g proved ineffective. In the recovery room, the anesthesiologist performed a transthoracic echocardiogram (TTE) that revealed an extrinsic compression of the posterior left atrial wall by a circular hyperechogenic structure (Fig. 1, panel B). A computed tomography scan confirmed that the structure was an esophageal stent that had been invaded by the tumour (Fig. 2). The left ventricular ejection fraction was approximately 50%, which allowed the physicians to attempt cardioversion by intravenous administration of amiodarone 300 mg. The patient’s heart rate normalized within one hour, and general anesthesia was then performed. New onset AF with poor tolerance or uncontrolled heart rate in the preoperative setting is a rare condition, and

Peri‐operative intravenous administration of magnesium sulphate and postoperative pain: a meta‐analysis

Intravenous magnesium has been reported to improve postoperative pain; however, the evidence is inconsistent. The objective of this quantitative systematic review is to evaluate whether or not the peri-operative administration of intravenous magnesium can reduce postoperative pain. Twenty-five trials comparing magnesium with placebo were identified. Independent of the mode of administration (bolus or continuous infusion), peri-operative magnesium reduced cumulative intravenous morphine consumption by 24.4% (mean difference: 7.6 mg, 95% CI -9.5 to -5.8 mg; p < 0.00001) at 24 h postoperatively. Numeric pain scores at rest and on movement at 24 h postoperatively were reduced by 4.2 (95% CI -6.3 to -2.1; p < 0.0001) and 9.2 (95% CI -16.1 to -2.3; p = 0.009) out of 100, respectively. We conclude that peri-operative intravenous magnesium reduces opioid consumption, and to a lesser extent, pain scores, in the first 24 h postoperatively, without any reported serious adverse effects.

Does Intravenous Magnesium Benefit Patients of Cardiac Arrest? a Meta-Analysis

Objective Evidence shows that magnesium has anti-arrhythmic roles. However, clinical trials suggest that there are conflicting outcomes of cardiac arrest patients given magnesium. The study aimed to examine the effects of magnesium sulfate therapy on cardiac arrest patients using a meta-analysis. Methods We searched the MEDLINE (1966-July 2011), OVID (1980-July 2011), EMBASE (1980-July 2011), Chinese bio-medical literature &amp; retrieval system (1978-July 2011), Chinese medical current contents (1995-July 2011), and Chinese medical academic conference (1994-July 2011). Studies were included if (1) the study design was a randomised controlled trial (RCT); (2) the study population included cardiac arrest patients who received cardiopulmonary resuscitation and either intravenous magnesium or placebo (0.9% normal saline); (3) the study provided data on return of spontaneous circulation (ROSC) and survival to hospital discharge. Relative risk (RR) and 95% confidence interval (CI) were used to pool the effect. Results The study included six RCTs with a total of 531 participants from cardiac arrest. The pooled data demonstrated that ROSC and hospital discharge rates in patients treated with magnesium were 35.5% (95% CI=29.7%-41.3%) and 10.4% (95% CI=6.7%-14.1%) compared with placebo (ROSC rate: 31.3%, 95% CI=25.8%-36.8%; hospital discharge rate: 8.5%, 95% CI=5.2%-11.8%). Administration of intravenous magnesium sulfate could not significantly increase ROSC (RR=1.14, 95% CI=0.91-1.43, P=0.26) and survival to hospital discharge (RR=1.22, 95% CI=0.74-2.02, P=0.43) compared with placebo. Conclusions Administration of magnesium sulfate does not improve ROSC and survival to hospital discharge in patients of cardiac arrest.

Anesthesia for pheochromocytoma resection in a child with Fontan circulation

To report the anesthetic management of a successful resection of a pheochromocytoma in a child with a completed Fontan circulation. The patient was an 11-yr-old boy with Ivemark syndrome who had undergone Fontan palliation at three years of age. Six weeks earlier, he had been diagnosed with a norepinephrine-producing pheochromocytoma, and he had been pretreated with oral propranolol and phenoxybenzamine. During surgery, intravenous administration of magnesium sulphate, esmolol, and phentolamine provided good hemodynamic control. Postoperatively, the patient tended to be hypotensive, and treatment with fluid administration resulted in prolonged intensive care. Although intraoperative management was not problematic, postoperative care of this 11-yr old child with pheochromocytoma was complicated by residual sympathetic blockade.

Is magnesium sulfate by the intrathecal route efficient and safe?

The polypharmacological approach to the treatment of postoperative pain has become routine in an attempt to minimize the adverse side effects of opioids. Magnesium sulphate is a noncompetitive antagonist of the N-methyl- d-aspartate (NMDA) receptor and thus can modify nociceptive modulation. Intravenous administration of magnesium sulphate can improve postoperative analgesia and decrease the requirement for postoperative opiates, but the effects are inconsistent and have not been reliably accompanied by a reduction in the incidence of morphine-related adverse events. Several studies have shown that the administration of magnesium by the intrathecal route is safe and, in combination with opiates, extends the effect of spinal anaesthesia in both animal and human studies. The analysis of these studies justifies further investigation of the use of magnesium sulphate by the intrathecal route.

Anesthesia Literature Review

Anesthesia Literature Review

Prophylactic intravenous magnesium sulfate for treatment of aneurysmal subarachnoid hemorrhage: A randomized, placebo-controlled, clinical study*

To examine whether the maintenance of elevated magnesium serum concentrations by intravenous administration of magnesium sulfate can reduce the occurrence of cerebral ischemic events after aneurysmal subarachnoid hemorrhage. Prospective, randomized, placebo-controlled study. Neurosurgical intensive care unit of a University hospital. One hundred ten patients were randomized to receive intravenous magnesium sulfate or to serve as controls. Magnesium treatment was started with a bolus of 16 mmol, followed by continuous infusion of 8 mmol/hr. Serum concentrations were measured every 8 hrs, and infusion rates were adjusted to maintain target levels of 2.0-2.5 mmol/L. Intravenous administration was continued for 10 days or until signs of vasospasm had resolved. Thereafter, magnesium was administered orally and tapered over 12 days. Delayed ischemic infarction (primary end point) was assessed by analyzing serial computed tomography scans. Transcranial Doppler sonography and digital subtraction angiography were used to detect vasospasm. Delayed ischemic neurologic deficit was determined by continuous detailed neurologic examinations; clinical outcome after 6 months was assessed using the Glasgow outcome scale. Good outcome was defined as Glasgow outcome scale score 4 and 5.The incidence of delayed ischemic infarction was significantly lower in magnesium-treated patients (22% vs. 51%; p = .002); 34 of 54 magnesium patients and 27 of 53 control patients reached good outcome (p = .209). Delayed ischemic neurologic deficit was nonsignificantly reduced (9 of 54 vs. 15 of 53 patients; p = .149) and transcranial Doppler-detected/angiographic vasospasm was significantly reduced in the magnesium group (36 of 54 vs. 45 of 53 patients; p = .028). Fewer patients with signs of vasospasm had delayed cerebral infarction. These data indicate that high-dose intravenous magnesium can reduce cerebral ischemic events after aneurysmal subarachnoid hemorrhage by attenuating vasospasm and increasing the ischemic tolerance during critical hypoperfusion.

Effect of the Loading Dose of Magnesium Sulfate (MgSO4) on the Parameters of Doppler Flow Velocity in the Uterine, Umbilical and Middle Cerebral Arteries in Severe Preeclampsia

Objective. To evaluate Doppler velocimetry parameters (resistance index [RI], pulsatility index [PI] and systolic/diastolic [S/D] ratio) of maternal-fetal circulation before and after magnesium sulfate administration in pregnant women with severe preeclampsia. Methods. A prospective observational cohort analysis of 40 women with severe preeclampsia was performed. Doppler ultrasonography scans were performed before and 20 minutes after intravenous administration of magnesium sulfate. Maternal parameters such as heart rate, and systolic, diastolic and mean arterial pressure were recorded. Doppler flow velocity parameters (RI, PI and S/D ratio) were evaluated in the uterine, umbilical and middle cerebral arteries. The different mean values obtained before and after magnesium sulphate were analyzed using the paired t-test. Results. There was a statistically significant increase in mean maternal heart rate and a statistically significant decrease in systolic, diastolic and mean maternal blood pressure before and after administration of magnesium sulphate (p < 0.001). Resistance index decreased in the umbilical (p = 0.003; 95% CI: 0.008 - 0.03) and middle cerebral artery (p = 0.001; 95% CI: 0.01 - 0.05) and in both uterine arteries. Likewise, there was a significant reduction in the PI and S/D ratio in all the arteries assessed. Conclusions. Maternal administration of intravenous magnesium sulfate in preeclampsia leads to an increase in maternal heart rate and a decrease in systolic, diastolic and mean arterial blood pressure. A reduction in the resistance index, pulsatility index and S/D ratio was recorded in the uterine, umbilical and cerebral arteries.

Doppler das artérias umbilicais e cerebral média fetal após sulfato de magnésio na pré-eclâmpsia

To compare the ratio between the fetal middle cerebral artery and the umbilical artery using Doppler flow velocimetry indices (resistance index, pulsatility index and A/B relation) before and after administration of magnesium sulfate to pregnant women with severe preeclampsia (pure or superimposed). A prospective cohort study was conducted with each pregnant woman representing her own control. Forty severe preeclamptic women were included and underwent Doppler sonography before and 20 minutes after administration of 6g of magnesium sulfate. Analysis variables were the Doppler flow velocimetry indices evaluating the ratio of the fetal middle cerebral artery to the umbilical artery. To compare the mean indices before and after magnesium sulfate for the same patient, the "t-paired" Student test was used. The Stuart-Maxwell c(2) was applied to determine the difference of fetal diagnosis (normal, brain-sparing or reduced middle cerebral artery resistance) before and after magnesium sulfate. No significant difference of the mean ratio between the middle cerebral artery and the umbilical artery, before and after administration of magnesium sulfate was observed. After magnesium sulfate (25.0% x 47.5%; p= 0.01), there was an increased frequency of isolated lower Doppler flow velocimetry indices in the middle cerebral artery. Intravenous administration of magnesium sulfate in patients with severe preeclampsia is associated with increased frequency of fetal Doppler diagnosis of reduced resistance in the middle cerebral artery.

Abbreviated Postpartum Magnesium Sulfate Therapy for Women with Mild Preeclampsia. A Randomized Controlled Trial

Preeclampsia complicates 5 to 8% of all deliveries. Standard treatment consists of management of hypertension, delivery, and administration of intravenous magnesium sulfate for 24 hours. Recently there has been interest in shortening the time for magnesium therapy in women at low risk of developing preeclampsia, in order to shorten the stay in the labor and delivery unit, decrease costs, and minimize the duration of magnesium-associated symptoms. The investigators prospectively compared the treatment of mild preeclampsia for 12 hours to treatment for 24 hours. Study patients were 34 weeks' gestation or more and had mild preeclampsia as defined by new onset blood pressure of 140 mm Hg or greater systolic and 90 mm Hg or greater diastolic, at least 1+ proteinuria, and the absence of symptoms or laboratory findings consistent with severe preeclampsia. The diagnosis was made either before or within two hours after delivery, before discharge from the labor and delivery unit. Magnesium sulfate was given as a 4 gram IV bolus followed by an infusion of 2 grams per hour, and IV fluids were maintained at a total rate of 125 ml per hour. Randomization was by computer-generated random number table distributed in blocks of 10. Study patients who were clinically stable at the end of their prescribed MgSO4 infusion were sent to the postpartum ward, while those with continued hypertension or symptoms remained on labor and delivery for additional MgSO4 therapy. Of a total of 322 patients with suspected mild preeclampsia, 204 were eligible and 200 were enrolled. Four patients were lost to follow up. The groups receiving either 12 or 24 hours of MGSO4 were similar in terms of the severity of their preeclampsia and history of chronic hypertension or diabetes. One patient in the 24 hour group required additional MgSO4 therapy. Seven in the 12 hour group required additional therapy, and 3 of these had chronic hypertension, three had diabetes, and two had both. Both groups tolerated the MgSO4 well, and no patients experienced seizures or toxicity. The length of the postpartum stay was the same in both groups. These data indicate that selected women with mild preeclampsia can safely receive 12 hours of IV MgSO4 therapy instead of 24 hours. Women with chronic hypertension or diabetes require 24 hours of therapy.

Effect of Intravenous Magnesium Sulfate on Chronic Obstructive Pulmonary Disease Exacerbations Requiring Hospitalization: a Randomized Placebo-Controlled Trial

Magnesium sulfate has been shown to have a bronchodilating effect in asthma, but this effect has not been clearly established in the context of chronic obstructive pulmonary disease (COPD). For this reason we investigated the possible bronchodilating effect of magnesium sulfate in COPD exacerbations. We studied 24 patients with exacerbated COPD who required admission to our hospital's pneumology department. All patients underwent baseline spirometry and were subsequently randomized to groups in a double-blind crossover design. Patients received 1.5 g of magnesium sulfate or placebo in an intravenous solution for 20 minutes. Those who received magnesium sulfate the first day were given placebo the second day, and vice versa. Spirometry was performed 15, 30, and 45 minutes after administration of magnesium sulfate or placebo. Finally, 400 microg of salbutamol were administered using a spacer and a final spirometry was performed 15 minutes later. All patients also received treatment with corticosteroids, intravenous antibiotics, oxygen, and regularly-scheduled bronchodilator therapy (salbutamol and ipratropium bromide every 6 hours). When we compared absolute increase in milliliters and percentage increase in forced expiratory volume in 1 second (FEV1) obtained with magnesium sulfate application to the increases obtained with placebo after 15, 30, and 45 minutes, no significant differences were found. When we compared absolute and percentage increases in FEV1 after administering salbutamol, we found significantly greater increases after magnesium sulfate administration. The mean (SD) absolute increase in FEV1 was 0.18 [corrected] (0.42) L after magnesium sulfate administration and 0.081 [0.01] L after placebo (P=.004). The percentage increase in FEV1 was 17.11% (3.7%) after magnesium sulfate and 7.06% (1.8%) after placebo (P=.008). Intravenous administration of magnesium sulfate has no bronchodilating effect in patients with COPD exacerbations. It does, however, enhance the bronchodilating effect of inhaled ss2-agonists.

Intravenous Magnesium Sulfate May Relieve Restless Legs Syndrome in Pregnancy

We report a case of restless legs syndrome that improved after intravenous magnesium sulfate administration. A 34-year-old gravida 1 para 0 woman, with a 13-year history of restless legs syndrome, was prescribed bed rest due to pre-term labor at 26 weeks. While at rest, the subject experienced severe restless legs syndrome. The subject was later admitted to the hospital for pre-term labor. Treatment for pre-term labor included intravenous magnesium sulfate. RLS symptoms completely resolved during treatment, beginning the first day of administration. Studies involving intravenous magnesium treatment for restless legs syndrome have not included pregnant women. The authors propose that intravenous magnesium sulfate may alleviate restless legs syndrome in some pregnant women.

Intravenous Magnesium for Neuroprotection in Acute Stroke: Clinical Hope Versus Basic Neuropharmacology

To the Editor: Saver and colleagues investigated the neuroprotective effect of early magnesium infusion in ischemic or hemorrhagic stroke in the field; three quarters of the infarct cohort were treated within 2 hours of onset, and nearly one-third within 1 hour of onset.1 Dramatic early and good results were reported in the early (42% of <2-hour infarct patients) and 90-day global functional outcomes (69% of all patients and 75% of <2 hour infarct patients), respectively. These authors recommend large-scale trials with field initiation of magnesium for early neuroprotection in stroke. An essential prerequisite for any pharmacological agent to offer significant brain neuronal protection during strokes is its ability to freely cross the blood–brain barrier (BBB). Transport of magnesium from blood to cerebrospinal fluid across BBB is limited in normal humans; intravenous administration of magnesium sulfate does not increase …

Optimal Administration Dosage of Magnesium Sulfate for Torsades de Pointes in Children with Long QT Syndrome

Background: Intravenous administration of magnesium sulphate (MgSO4) is a very effective and safe treatment for torsades de pointes (TdP) associated with acquired long QT syndrome (LQTS) in adults. Discussed here is the efficacy of MgSO4 for TdP in children with congenital and acquired LQTS.Methods: The optimal MgSO4 dosage and serum magnesium (SMg) was determined in six consecutive children with TdP; four had congenital LQTS and two had acquired LQTS. A bolus injection of MgSO4 was given intravenously over 1 to 2 minutes followed by continuous infusion for the next 2 to 7 days.Results: Of the six patients, five responded completely to the initial bolus of 6.1 ± 4.2 mg/kg (range, 2.3–12 mg/kg). One (a neonate with congenital LQTS) required a total of 30 mg/kg until complete TdP elimination. Continuous infusion was given at rates of 0.3 to 1.0 mg/kg/hr with no recurrence of TdP. SMg concentration was 3.9 ± 1.0 mg/dL (2.9–5.4 mg/dL) immediately after bolus injection.Conclusion: Intravenous MgSO4 infusion effectively treated TdP in children with LQTS. Optimal bolus dosage, infusion rates and SMg concentration were 3 to 12 mg/kg, 0.5 to 1.0 mg/kg/hr and 3 to 5 mg/dL, respectively.