Pharmacology, Pathophysiology and Management of Calcium Channel Blocker and ??-Blocker Toxicity

A Survival Case of High-Dose Amlodipine Intoxication With Unusual Manifestation of Type 2 Respiratory Failure

Amlodipine, a calcium channel blocker of the dihydropyridine class, is frequently used to treat high blood pressure. While overdoses are rare, they can result in significant cardiovascular compromise and, infrequently, respiratory failure. We report the case of a 17-year-old male patient who presented with an intentional amlodipine overdose, and his clinical course was complicated by type 2 (hypercapnic) respiratory failure, necessitating mechanical ventilation and intensive care management. He achieved full recovery with fluid resuscitation, calcium supplementation, high-dose insulin euglycemic therapy, vasopressor support, lung-protective ventilation, and supportive therapy. This case report highlights the importance of early detection and timely management of amlodipine toxicity, which can lead to severe complications such as cardiovascular instability, fluid overload, and respiratory distress with type 2 respiratory failure.

In vivo toxic and lethal cardiorespiratory effects of a synthetic quaternary ammonium salt derivative of haloperidol in mice

BACKGROUND

To investigate the toxicity of N-n-butyl haloperidol iodide (F2), a quaternary ammonium salt derivative of haloperidol, in mice for potential therapeutic purposes.

METHODS

The acute median lethal dose (LD50) of F2 was determined using the Bliss method following intravenous administration in mice. Routine surface electrocardiograms (ECGs) and arterial blood pressures (aBPs) were recorded under general anesthesia in untreated and pharmacologically vagotomized mice injected with F2. Sublethal doses of F2 were tested for their effects on aBP, heart rate, and biochemical parameters such as lactate dehydrogenase (LDH), blood urea nitrogen (BUN), and serum lactate levels. Histopathological changes in the heart, lungs, liver, and kidneys were evaluated after F2 administration.

RESULTS

The acute LD50 of F2 was determined to be 5.11 mg/kg. A 10 mg/kg dose of F2 caused severe hypotension, second-degree atrioventricular block, progressive prolongation of Pmurr intervals, and death due to cardiac asystole. Similar ECG and aBP changes were observed in atropine-pretreated mice, indicating that cholinergic effects do not play a major role in F2-induced toxicity. Sublethal doses of F2 (1.2 and 2.4 mg/kg) caused dose-dependent decreases in aBP and increases in heart rate. F2 induced significant, dose-dependent increases in LDH, BUN, and serum lactate levels. Histopathological analysis revealed acute lung lesions at 10 mg/kg, with no significant changes observed in the heart, liver, or kidneys.

CONCLUSION

Acute intravenous injection of F2 exhibits dose-dependent cardiopulmonary toxicity, characterized by severe hypotension, arrhythmias, and biochemical changes. These findings highlight the potential risks of F2 and the need for further evaluation of its safety profile for therapeutic use.

Cholestasis due to biliary obstruction can cause cardiogenic shock with bradycardia by delaying the elimination of arotinolol

Cardiogenic shock with bradycardia due to beta-blockers is well-documented; however, this condition in association with arotinolol is unreported. We present a case of cardiogenic shock resulting from delayed arotinolol clearance caused by bile duct obstruction. A man in his 60s presented to our hospital with jaundice. We suspected acute obstructive suppurative cholangitis; however, the patient did not exhibit fever or abdominal symptoms. Based on the physical examination results, we concluded the patient was in cardiogenic shock as a consequence of delayed arotinolol elimination. We attempted to maintain organ perfusion using norepinephrine and dopamine, with minimal response. On initiating isoproterenol, the heart rate stabilised. After tapering off isoproterenol, endoscopic retrograde cholangiopancreatography (ERCP) was performed. Subsequent serum arotinolol level measurement revealed a significant reduction in the elimination half-life before and after ERCP. In cases of cardiogenic shock associated with arotinolol, presumably eliminated via the bile duct, it is crucial to consider potential delayed elimination and to appropriately time ERCP.

High-Dose Insulin Therapy for Refractory Shock in a Polypharmacy Overdose of Calcium Channel Blocker and Oral Hypoglycemic Agent: A Case Report and Literature Review

We report a case of polypharmacy overdose involving a calcium (Ca) channel blocker and an oral hypoglycemic agent, where conventional therapies failed to obtain the desired clinical outcome. High-dose insulin (HDI) therapy, a promising treatment regime in this regard, was carried out for our patient, and her condition improved over the subsequent days.

Calcium channel blockers and beta blockers in pediatric supraventricular tachycardia

INTRODUCTION

Supraventricular tachycardia (SVT) is a common pediatric arrhythmia. Beta blockers (BBs) and calcium channel blockers (CCBs) are used for treatment despite little data examining their use. We describe the prescriptive tendencies, efficacy, and tolerability of BBs and CCBs used in the treatment of pediatric SVT.

METHODS AND RESULTS

This is a multicenter retrospective cohort study from three academic children's hospitals. Individuals aged 1-21 years at time of SVT diagnosis initiated on a BB or a CCB between 01/01/2010 and 12/31/2020 were included. Exclusion criteria were pre-excitation, ectopic atrial tachycardia, and hemodynamically significant heart disease. Demographic, comorbidity, symptomatology, and medication data were collected. Treatment success was defined using a composite data abstraction tool. Of 164 patients, 151 received a BB and 13 received a CCB. The success rate on the initial dosage was 46% for both BB and CCB; the success rate following dosage adjustments was also comparable for BBs (98/151, 65%) and CCBs (9/13, 69%). While 27 (18%) BB patients experienced intolerable side effects, no CCB patient did.

CONCLUSION

Treatment with a BB or CCB was successful in half of patients. BBs were prescribed more frequently than CCBs but were associated with more side effects.

Single-Dose Calcium Channel Blocker Toxicity in a Patient With Severe Liver Disease

Calcium channel blockers (CCBs) are commonly used in the management of multiple diseases, including hypertension, arrhythmia, and vasospastic disorder. Nimodipine, a dihydropyridine CCB, has demonstrated utility in preserving hearing following vestibular schwannoma resection surgery. Due to its widespread use, CCB overdose is common. This case report presents a unique case of CCB toxicity in a 56-year-old female with end-stage liver dysfunction. The patient developed vasodilatory shock after receiving a single dose of prophylactic nimodipine following vestibular schwannoma surgery. The primary objective of this report is to highlight the unique risk for CCB toxicity that exists for patients with advanced liver disease who receive nimodipine in the perioperative setting.

Drug-induced myocarditis precipitated by amlodipine overdose: a case report

Background

Amlodipine is the most commonly prescribed calcium channel blocker (CCB), used in the treatment of a variety of cardiovascular conditions. Calcium channel blockers remain a well-established cause of cardiovascular drug overdose. We present the case of an intentional overdose with 250 mg of amlodipine resulting in acute left ventricular dysfunction and myocarditis.

Case summary

A 46-year-old man with no significant past medical history presented to the emergency department 8 h after intentionally ingesting 250 mg of amlodipine. Although initially asymptomatic with unremarkable physical examination, the patient developed progressively worsening dyspnoea over the next 2 days. Subsequent findings from chest X-ray, electrocardiogram, echocardiogram, and cardiac magnetic resonance imaging (MRI) were consistent with a diffuse myocarditis process with severe left ventricular systolic dysfunction. The patient was managed with diuretics and discharged once stable.

Discussion

Our case highlights myocarditis as a potential complication of CCB overdose. Amlodipine is the most commonly prescribed CCB and is associated with cardiac toxicity at high doses. The long duration of action and high volume of distribution of amlodipine further increase the risk of morbidity and mortality from overdose. Known cardiac complications of amlodipine overdose include bradycardia, myocardial depression, and pulmonary oedema secondary to heart failure; however, diffuse myocarditis is a complication that has not previously been described in the literature. The mechanism of development of this complication remains unclear.

S-amlodipine induces liver inflammation and dysfunction through the alteration of intestinal microbiome in a rat model

S-amlodipine, a commonly prescribed antihypertensive agent, is widely used in clinical settings to treat hypertension. However, the potential adverse effects of long-term S-amlodipine treatment on the liver remain uncertain, given the cautionary recommendations from clinicians regarding its administration in individuals with impaired liver function. To address this, we conducted a study using an eight-week-old male rat model and administered a daily dose of 0.6 ~ 5 mg/kg of S-amlodipine for 7 weeks. Our findings demonstrated that 1.2 ~ 5 mg/kg of S-amlodipine treatment induced liver inflammation and associated dysfunction in rats, further in vitro experiments revealed that the observed liver inflammation and dysfunction were not attributable to direct effects of S-amlodipine on the liver. Metagenome sequencing analysis revealed that S-amlodipine treatment led to alterations in the gut microbiome of rats, with the bloom of E. coli (4.5 ~ 6.6-fold increase) and a decrease in A. muciniphila (1,613.4 ~ 2,000-fold decrease) and B. uniformis (20.6 ~ 202.7-fold decrease), subsequently causing an increase in the gut bacterial lipopolysaccharide (LPS) content (1.4 ~ 1.5-fold increase in feces). S-amlodipine treatment also induced damage to the intestinal barrier and increased intestinal permeability, as confirmed by elevated levels of fecal albumin; furthermore, the flux of gut bacterial LPS into the bloodstream through the portal vein resulted in an increase in serum LPS content (3.3 ~ 4-fold increase). LPS induces liver inflammation and subsequent dysfunction in rats by activating the TLR4 pathway. This study is the first to show that S-amlodipine induces liver inflammation and dysfunction by perturbing the rat gut microbiome. These results indicate the adverse effects of S-amlodipine on the liver and provide a rich understanding of the safety of long-term S-amlodipine administration.

Association of antihypertensive drugs with COVID-19 outcomes: a drug-target Mendelian randomization study

Background: Observational investigations have provided conflicting results regarding the effect of antihypertensive drugs on the risk of COVID-19 outcomes. We intended to assess the causal effect of antihypertensive drugs on COVID-19 outcomes using drug-target Mendelian randomization (MR), mainly including angiotensin-converting enzyme inhibitors (ACEIs), β-blockers (BBs) and calcium channel blockers (CCBs). Methods: We used the genetic variants (minor allele frequency >1%, r 2 < 0.30) located within 100 k bases of each drug target gene and associated with lower systolic blood pressure (p < 5 × 10-8) as genetic proxies for antihypertensive drugs. COVID-19 outcomes included COVID-19 susceptibility (122,616 cases and 2,475,240 controls), hospitalization (32,519 cases and 206,2805 controls), and severe illness (13,769 cases and 1,072,442 controls). All studies were conducted on populations of European ancestry. MR estimates were generated using an inverse variance weighted (IVW) model. Results: IVW-MR analysis observed a weak causality between CCBs and COVID-19 susceptibility (OR: 0.993, 95% CI: 0.988-0.999, p = 0.012). Sensitivity analysis suggested that this result was robust. No evidence was found for a link between other antihypertensive drugs and COVID-19 outcomes. Conclusion: The present study suggests that CCBs may reduce COVID-19 susceptibility in European populations.

2023 American Heart Association Focused Update on the Management of Patients With Cardiac Arrest or Life-Threatening Toxicity Due to Poisoning: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

In this focused update, the American Heart Association provides updated guidance for resuscitation of patients with cardiac arrest, respiratory arrest, and refractory shock due to poisoning. Based on structured evidence reviews, guidelines are provided for the treatment of critical poisoning from benzodiazepines, β-adrenergic receptor antagonists (also known as β-blockers), L-type calcium channel antagonists (commonly called calcium channel blockers), cocaine, cyanide, digoxin and related cardiac glycosides, local anesthetics, methemoglobinemia, opioids, organophosphates and carbamates, sodium channel antagonists (also called sodium channel blockers), and sympathomimetics. Recommendations are also provided for the use of venoarterial extracorporeal membrane oxygenation. These guidelines discuss the role of atropine, benzodiazepines, calcium, digoxin-specific immune antibody fragments, electrical pacing, flumazenil, glucagon, hemodialysis, hydroxocobalamin, hyperbaric oxygen, insulin, intravenous lipid emulsion, lidocaine, methylene blue, naloxone, pralidoxime, sodium bicarbonate, sodium nitrite, sodium thiosulfate, vasodilators, and vasopressors for the management of specific critical poisonings.

Glucagon and Its Receptors in the Mammalian Heart

Glucagon exerts effects on the mammalian heart. These effects include alterations in the force of contraction, beating rate, and changes in the cardiac conduction system axis. The cardiac effects of glucagon vary according to species, region, age, and concomitant disease. Depending on the species and region studied, the contractile effects of glucagon can be robust, modest, or even absent. Glucagon is detected in the mammalian heart and might act with an autocrine or paracrine effect on the cardiac glucagon receptors. The glucagon levels in the blood and glucagon receptor levels in the heart can change with disease or simultaneous drug application. Glucagon might signal via the glucagon receptors but, albeit less potently, glucagon might also signal via glucagon-like-peptide-1-receptors (GLP1-receptors). Glucagon receptors signal in a species- and region-dependent fashion. Small molecules or antibodies act as antagonists to glucagon receptors, which may become an additional treatment option for diabetes mellitus. Hence, a novel review of the role of glucagon and the glucagon receptors in the mammalian heart, with an eye on the mouse and human heart, appears relevant. Mouse hearts are addressed here because they can be easily genetically modified to generate mice that may serve as models for better studying the human glucagon receptor.

Amlodipine Overdose in a Transgender Woman: A Case Study

Calcium channel blockers are a major cause of cardiovascular toxicity. The clinical spectrum of these patients is very variable and there is no consensus on the dose required for toxicity. We present a case of a 43-year-old transgender woman who presented with hypotension and tachycardia owing to drug overdose that was later confirmed to be amlodipine. Given the catastrophic cascade of events involved with such toxicities, it is important to highlight amlodipine as one of the causes of drug overdose that can be overlooked.

A Combination of Beta-Blockade and Calcium Channel Blockade Leading to Bradycardia, Renal Failure, Atrioventricular Blockade, Shock, and Hyperkalemia (BRASH) Syndrome: A Case Report

The BRASH syndrome is a recently recognized syndrome and the acronym stands for bradycardia, renal failure, atrioventricular (AV) blockade, shock, and hyperkalemia. We discuss a case of a 56-year-old female with a history of heart failure who presented in a critical state following recent adjustments to her carvedilol dosage while she was simultaneously on verapamil. This combination of AV nodal-blocking agents induced bradycardia in the patient, leading to shock and renal hypoperfusion complicated by hyperkalemia that required the use of a temporary transvenous pacemaker before she made a full recovery. The case report highlights the fact that this combination of medications alone may have had a synergistic effect that led to BRASH in our patient.

Evidence for a lack of inotropic and chronotropic effects of glucagon and glucagon receptors in the human heart

BACKGROUND

Glucagon is thought to increase heart rate and contractility by stimulating glucagon receptors and increasing 3',5'-cyclic adenosine monophosphate (cAMP) production in the myocardium. This has been confirmed in animal studies but not in the human heart. The cardiostimulatory effects of glucagon have been correlated with the degree of cardiac dysfunction, as well as with the enzymatic activity of phosphodiesterase (PDE), which hydrolyses cAMP. In this study, the presence of glucagon receptors in the human heart and the inotropic and chronotropic effects of glucagon in samples of failing and nonfailing (NF) human hearts were investigated.

METHODS

Concentration‒response curves for glucagon in the absence and presence of the PDE inhibitor IBMX were performed on samples obtained from the right (RA) and left atria (LA), the right (RV) and left ventricles (LV), and the sinoatrial nodes (SNs) of failing and NF human hearts. The expression of glucagon receptors was also investigated. Furthermore, the inotropic and chronotropic effects of glucagon were examined in rat hearts.

RESULTS

In tissues obtained from failing and NF human hearts, glucagon did not exert inotropic or chronotropic effects in the absence or presence of IBMX. IBMX (30 µM) induced a marked increase in contractility in NF hearts (RA: 83 ± 28% (n = 5), LA: 80 ± 20% (n = 5), RV: 75 ± 12% (n = 5), and LV: 40 ± 8% (n = 5), weaker inotropic responses in the ventricular myocardium of failing hearts (RV: 25 ± 10% (n = 5) and LV: 10 ± 5% (n = 5) and no inotropic responses in the atrial myocardium of failing hearts. IBMX (30 µM) increased the SN rate in failing and NF human hearts (27.4 ± 3.0 beats min^-1, n = 10). In rat hearts, glucagon induced contractile and chronotropic responses, but only contractility was enhanced by 30 µM IBMX (maximal inotropic effect of glucagon 40 ± 8% vs. 75 ± 10%, in the absence or presence of IBMX, n = 5, P < 0.05; maximal chronotropic response 77.7 ± 6.4 beats min^-1 vs. 73 ± 11 beats min^-1, in the absence or presence of IBMX, n = 5, P > 0.05). Glucagon receptors were not detected in the human heart samples.

CONCLUSIONS

Our results conflict with the view that glucagon induces inotropic and chronotropic effects and that glucagon receptors are expressed in the human heart.

Hydroxocobalamin as Rescue Therapy in a Patient With Refractory Amlodipine-Induced Vasoplegia

Vasoplegic syndrome is a type of distributive shock characterized by mean arterial pressure of less than 65 mmHg, with normal to high cardiac output and often refractory to fluid resuscitation, high doses of intravenous vasopressors, and inotropes. It is usually observed after cardiac and solid organ transplantation surgeries. Here, we report a 56-year-old female patient who presented with a profound vasoplegia manifesting as lethargy and confusion in the setting of amlodipine toxicity. This case of severe vasoplegia was refractory to all conditional lines of medical management reported in the literature. The mainstay treatment modalities for vasoplegia include volume resuscitation, catecholamines, vasopressin, angiotensin II, and possibly methylene blue in unresponsive cases. Our patient was given hydroxocobalamin in favor of methylene blue, given the history of serotonin reuptake inhibitors use, which would have caused a life-threatening serotonin syndrome. Hydroxycobolamine resulted in a dramatic clinical recovery, suggesting its potentially significant role in refractory vasoplegia.

Unique Case of Cardiogenic Shock in the Setting of Cumulative Calcium Channel Blocker Toxicity

Calcium channel blockers (CCBs) are the most prescribed medications in clinical practice. These drugs treat many conditions, including migraine headaches, vasospasms, abnormal heart rhythms, and hypertension. This widespread use, however, has also been linked with the increased incidence of CCB toxicity cases. CCB toxicity may be from accidental ingestion or iatrogenic. Patients may show signs of cardiovascular toxicity such as hypotension, bradyarrhythmia, coma, or even death. The treatment includes discontinuing the offending medication, securing the airway, and raising blood pressure. Herein, we report a rare case of a 40-year-old male with a history of uncontrolled hypertension and advanced kidney disease who experienced iatrogenic cumulative calcium channel blocker toxicity while switching CCB classes due to a hypertensive emergency with concomitant atrial flutter. Although uncommon in clinical practice, iatrogenic CCB toxicity is possible and equally lethal. Clinicians must be cautious when initiating these drugs, switching between oral and intravenous formulations, or switching from one class to another to avoid overdoses.

Acute Intoxication by Bisoprolol and Drowning: Toxicological Analysis in Complex Suicides

In complex suicides, more than one suicide method is applied at the same time or one after the other. The most common complex suicide includes the ingestion of drugs combined with drowning. A case of acute intoxication by Bisoprolol and drowning is reported. The dead body of a 40-year-old woman was discovered on a river side, soon after her husband found a suicide note at home. In the woman’s vehicle four empty boxes of Bisoprolol, a widely used beta blocker, were also found. Main autopsy findings were consistent with drowning and represented by plume of froth at the mouth and nostrils with frothy fluid also in the airways, water into the stomach, and a remarkable pulmonary edema as a result of fluid aspiration. Toxicological analyses were performed on peripheral blood, urine and gastric content samples using liquid and gas chromatography, coupled with mass spectrometry. Toxicological results were negative for ethanol and other common drugs of abuse. High levels of bisoprolol were found in blood (7.54 mg/L), far exceeding the therapeutic range, in the urine (1.14 mg/L), and gastric content (13.12 mg/L). Bisoprolol intoxication was assessed as a relevant contributing condition to the immediate cause of death represented by drowning. Although Bisoprolol would certainly have a heart-depressing effect, it is not possible to determine if the victim fell unconscious or if she simply collapsed into the water with a secondary drowning.

Amlodipine: Can act as an antioxidant in patients with transfusion-dependent β-thalassemia? A double-blind, controlled, crossover trial

BACKGROUND AND AIM

This study aimed to assess the antioxidant effects of amlodipine in transfusion-dependent β-thalassemia (TDT) patients.

METHODS

This crossover trial consisted of two sequences (AP and PA). In the AP sequence, nine cases received amlodipine 5 mg daily (phase I) and then were switched to placebo (phase II). In PA sequence, 10 patients took the placebo (phase I) and were shifted to amlodipine (phase II). The washout period was 2 weeks. The length of each phase was 6 months. Serum malondialdehyde (MDA, μmol/L), carbonyl (protein CO, μM/L), glutathione (GSH, nM/L), and total antioxidant capacity (TAC, μmol FeSO4/L) were measured in the beginning and at the end of phases I and II. The clinical significance was viewed as a minimum change difference of 5% for each outcome between amlodipine and placebo.

RESULTS

Seventeen cases completed the study. According to the baseline MDA values, the adjusted Hedges's g for MDA was -0.59, 95% confidence interval [CI] -1.26 to 0.08. After controlling the baseline protein CO values, Hedges's g computed for protein CO was -0.11, 95% CI -0.76 to 0.55. The estimated values of the adjusted Hedges's g for GSH and TAC were also 0.26, 95% CI -0.40 to 0.91, and 0.42, 95% CI -0.24 to 1.09, respectively. The change difference for MDA was 8.3% (protein CO 2.2%, GSH 3.1%, and TAC 12.9%).

CONCLUSION

Clinically, amlodipine therapy is an efficacious adjuvant treatment with conventional iron chelators for improving the levels of MDA and TAC in patients with TDT.

Calcium Channel Blocker Toxicity: A Practical Approach

Calcium channel blockers (CCBs) are widely prescribed medications for various clinical indications in adults and children. They are available in both immediate and long-acting formulations and are generally classified into dihydropyridines and nondihydropyridines, with nondihydropyridines having more cardioselectivity. CCB toxicity is common given the widespread use which leads to serious adverse clinical outcomes, especially in children. Severe CCB toxicities may present with life-threatening bradycardia, hypotension, hyperglycemia, and renal insufficiency. Dihydropyridine toxicity, however, may present with reflex tachycardia instead of bradycardia. Initial patient evaluation and assessment are crucial to identify the severity of CCB toxicity and design the best management strategy. There are different strategies to overcome CCB toxicity that requires precise dosing and close monitoring in various patient populations. These strategies may include large volumes of IV fluids, calcium salts, high insulin euglycemia therapy (HIET), and vasopressors. We hereby summarize the evidence behind the management of CCB toxicity and present a practical guide for clinicians to overcome this common drug toxicity.

Kardiyovasküler ilaç zehirlenmelerinin ileriye dönük analizi

Purpose: The aim of this study is to provide data about diagnosis, treatment, and results of the patients poisoned by drugs affecting the cardiovascular system. Materials and Methods: Patients aged 18 and over who applied to the emergency department with drug poisoning affecting cardiovasculer system were included in the study. The demographic data, drugs and doses, emergency treatment and the time of development of shock or bradycardia, treatment, antidotes and invasive procedures were recorded. Results: In our study twenty-five patients, 8 (32 %) male and 17 (68 %) female, were included. At the admission, 56 % (n=14) had hypotension, 8 % (n=2) had bradycardia, at the second hour 76 % (n=19) had hypotension, 16 % (n=4) had bradycardia. Within 6 hours after admission, 80 % (n=20) patients had hypotension, 28 % (n=7) patients had bradycardia at least once. Fifty-two percent (n=13) of the patients calcium, 36 % (n=9) glukagon, 32 % (n=8) lipid, 12 % (n=3) atropine, 20 % (n=5) positive inotropes were given. Conclusion: Lipid therapy produces positive results in patients who did not improve with calcium, glucagon and fluid therapy. Patients who received calcium channel blockers experienced more cardiogenic shock and bradycardia was more common in patients receiving beta-blockers.

Efficacy and safety of Abelmoschus manihot in treating chronic kidney diseases: A multicentre, open-label and single-arm clinical trial

RATIONALE AND OBJECTIVE

The efficacy of Abelmoschus manihot (AM) in treating of chronic kidney disease (CKD) has been confirmed by prior trials. AM is also commonly combined to other medicines among CKD patients in clinic. This trial aimed at evaluating the safety of AM combination application, and further verifying the efficacy of AM in treating various types of CKD.

STUDY DESIGN

A multicentre, prospective, open-label, single-arm trial SETTING AND PARTICIPANTS: Approximately 2000 CKD patients with proteinuria (≥ 150 mg/d), from 105 centres across China INTERVENTIONS: AM was administered to patients three times per day for 24 weeks: the daily dose was based on age (> 12 years old: 2.5 g tid; 6∼12 years old: 1.5 g tid; 2∼6 years old: 1 g tid) OUTCOMES: The efficacy outcomes were the change in 24-hour proteinuria and estimated glomerular filtration rate (eGFR) from baseline to week 24. Safety outcomes included adverse events and laboratory tests.

RESULTS

2054 CKD patients from 105 centres were enrolled in this trial, with 1843 (89.7%) completing the 24-week follow-up. The participants' median age was 44 years old and 44.6% were female. Compared to baseline, 24-hour proteinuria decreased 471 mg (95% confident interval, 367 to 575, p < 0.001) at week 24. eGFR did not change significantly relative to baseline with the mean increase as 1.7 ml/min/1.73 m2 (95% confident interval, -0.3 to 3.7, p = 0.09). 902 (43.9%) participants combined medication to AM during follow-up. The total incidence of adverse events was 12.9%; and the most common adverse events were hyperlipidaemia (4.1%), abnormal liver function (2.3%), upper respiratory infection (1.8%), and hyperglycaemia (1.1%). Combined medications did not change the risk for hyperlipidaemia and upper respiratory infection. The combination application with antiplatelet reagents increased the risk of abnormal liver function, and with calcium channel blockers increased the risk of hyperglycaemia.

LIMITATIONS

Single-arm clinical trial and short observation time CONCLUSION: We have provided safety information of AM on various types of CKD in a large trial, especially when combination to medications most commonly prescribed to CKD patients. AM also showed to decrease proteinuria with stable kidney function during follow up. AM is a promising treatment for CKD patients.

The Inhibition of the Small-Conductance Ca2+-Activated Potassium Channels Decreases the Sinus Node Pacemaking during Beta-Adrenergic Activation

Sinus pacemaking is based on tight cooperation of intracellular Ca²⁺ handling and surface membrane ion channels. An important player of this synergistic crosstalk could be the small-conductance Ca²⁺-activated K⁺-channel (I_SK) that could contribute to the sinoatrial node (SAN) pacemaking driven by the intracellular Ca²⁺ changes under normal conditions and beta-adrenergic activation, however, the exact role is not fully clarified. SK2 channel expression was verified by immunoblot technique in rabbit SAN cells. Ionic currents and action potentials were measured by patch-clamp technique. The ECG R-R intervals were obtained by Langendorff-perfusion method on a rabbit heart. Apamin, a selective inhibitor of SK channels, was used during the experiments. Patch-clamp experiments revealed an apamin-sensitive current. When 100 nM apamin was applied, we found no change in the action potential nor in the ECG R-R interval. In experiments where isoproterenol was employed, apamin increased the cycle length of the SAN action potentials and enhanced the ECG R-R interval. Apamin did not amplify the cycle length variability or ECG R-R interval variability. Our data indicate that I_SK has no role under normal condition, however, it moderately contributes to the SAN automaticity under beta-adrenergic activation.

Multi-organ dysfunction as a presentation of calcium channel blocker intoxication

SummaryWe report the case of a 73-year-old woman who intentionally ingested 400 mg of amlodipine in a suicidal attempt who initially presented with hypotension which persisted despite aggressive therapy with fluid resuscitation, multiple pressor support, high-dose insulin therapy and calcium infusion. Her haemodynamic instability evolved to include bradycardia requiring atropine and transcutaneous pacing. Eventually she required salvage therapy with intravenous lipid emulsion (ILE) therapy . Despite all aggressive therapy, she developed multi-organ failure resulting in death. The literature on high-dose insulin euglycaemic therapy (HIET) and ILE therapy shows mixed results with some showing significant improvement in haemodynamic status. In our case, it had no significant positive impact on the outcome.

A double-blind, controlled, crossover trial of amlodipine on iron overload status in transfusion dependent β-thalassemia patients

BACKGROUND AND AIM

This study examined whether administration of amlodipine could improve myocardial iron loading status in patients with transfusion dependent β-thalassemia (TDT), through a placebo-controlled, crossover study.

METHODS

Amlodipine (5 mg, daily) or placebo were prescribed to all patients (n = 19) for 6 months, and after a 2-week washout period, patients were crossed over to the other group. The efficacy of amlodipine on iron loading was assessed by measuring myocardial T2*-weighted magnetic resonance imaging (MRI T2*, millisecond [ms]) and serum ferritin (ng/mL).

RESULTS

Seventeen patients completed the study. The mean ± standard deviation [SD] of myocardial MRI T2* at baseline was 9.83 ± 2.67 ms Myocardial MRI T2* value rose to 11.44 ± 4.14 ms post amlodipine treatment in all patients. After placebo, myocardial MRI T2* value reached 10.29 ± 4.01 ms After controlling the baseline measures, Hedges's g for ferritin and myocardial MRI T2* outcomes were estimated 3.84 (95% confidence interval [CI] 2.68 to 4.97) and -1.80 (95% CI -2.58 to -0.10), respectively.

CONCLUSION

Amlodipine might improve myocardial MRI T2* and serum ferritin level compared to placebo. However, larger clinical studies are needed to confirm the results.

Efficacy of methylene blue in a murine model of amlodipine overdose

INTRODUCTION

Amlodipine overdoses have significant cardiac toxicity and are difficult to treat. Methylene blue has potential as a treatment for overdoses.

METHODS

A randomized controlled study of methylene blue as a treatment for amlodipine toxicity was conducted in C57Bl/6 mice. A baseline echocardiography was followed by gavage administration of amlodipine (90 mg/kg). Five minutes after gavage, animals received either vehicle solution (controls) or methylene blue (20 mg/kg) by intra-peritoneal injection. Animals were continuously monitored, and cardiac parameters were acquired every 15 min up to two hours.

RESULTS

Only 50% of control animals survived to the two-hour endpoint compared to 83% that received methylene blue. Amlodipine delivery induced significant reduction in left ventricular ejection fraction (EF), fractional shortening (FS), stroke volume (SV), and cardiac output (CO) in the vehicle treated animals relative to animals in the treatment group (p < 0.05 vehicle versus Methylene blue for EF, FS, SV, CO, and HR).

DISCUSSION

The amlodipine dose induced cardiotoxicity that were effects were more pronounced in the untreated group. 50% vehicle controls quickly progressed into heart failure (within 90 min of exposure) and did not survive the two h observation endpoint. Distinctly, only one animal from the Methylene blue treatment group did not survive (83% survival) the study. Additionally, the surviving animals from the Methylene blue group displayed significantly higher ejection fraction, fractional shortening, stroke volume, and cardiac output compared to vehicle group, indicating that methylene blue preserved cardiac function.

CONCLUSION

In this mouse model of amlodipine overdose, methylene blue decreased cardiac toxicity.

Influence of Trace Elements on Neurodegenerative Diseases of The Eye-The Glaucoma Model

Glaucoma is a heterogeneous group of chronic neurodegenerative disorders characterized by a relatively selective, progressive damage to the retinal ganglion cells (RGCs) and their axons, which leads to axon loss and visual field alterations. To date, many studies have shown the role of various elements, mainly metals, in maintaining the balance of prooxidative and antioxidative processes, regulation of fluid and ion flow through cell membranes of the ocular tissues. Based on the earlier and current research results, their relationship with the development and progression of glaucoma seems obvious and is increasingly appreciated. In this review, we aimed to summarize the current evidence on the role of trace elements in the pathogenesis and prevention of glaucomatous diseases. Special attention is also paid to the genetic background associated with glaucoma-related abnormalities of physiological processes that regulate or involve the ions of elements considered as trace elements necessary for the functioning of the cells.

A Stepwise Approach for Preventing Suicide by Lethal Poisoning

Background

Suicide is a global phenomenon and is the 10th leading cause of death in the US. Veterans are more likely to die by suicide than those in the general population. In 2018, the suicide rate for all US veterans was 1.5 times higher than the rate for nonveterans, after adjusting for population differences in age and sex. In light of this disparity, suicide prevention is one of the highest priorities for the US Department of Veterans Affairs (VA). One major goal of the VA suicide prevention strategy is to reduce access to lethal means.

Observations

This article will provide information on medications with high lethality and a stepwise approach for how health care providers may limit lethal medications for patients at high risk for suicide. The first step is to determine suicide risk. More than 90% of those who die by suicide have a psychiatric diagnosis at the time of death. Clinicians can use risk assessment tools, such as the Veterans Health Administration Suicide Prevention Population Risk Identification and Tracking for Exigencies tool. The second step is to identify substances strongly associated with fatalities. According to the American Association of Poison Control Centers, the pharmaceutical classes associated with the largest number of fatalities are stimulants and street drugs, followed by analgesics, cardiovascular agents, antidepressants, antipsychotics, and sedatives/hypnotics. The third step is to consider potential drug-drug interactions, such as the combination of opioids and sedative-hypnotics. Finally, clinicians need to address risks. With high-risk patients it may be preferential to prescribe medications that are less lethal. All patients with a high risk of suicide should receive lethal means counseling.

Conclusions

While firearms continue to be the most lethal means for veteran suicide, intentional poisoning with medications or substances also is a common method for suicide, especially for female veterans. Having knowledge of medications with high lethality and limiting access to these agents can be a successful strategy for reducing suicide deaths.

A Case Report of Loperamide-Induced Ventricular Storm

Loperamide is an easily accessible antidiarrheal medication. Unlike other medications in its class, loperamide is unique in that it causes euphoria at supratherapeutic levels due to its effect on opioid receptors. Unfortunately, with its growing abuse potential also comes increasing reports of cardiotoxicity including prolonged QT, torsades de pointes, and sudden cardiac death. We report a case of a 29-year-old female who presented with unstable arrhythmia that further progressed into electrical storm in the setting of loperamide toxicity. Due to its growing popularity and availability, it is important for clinicians to understand loperamide’s mechanisms for causing toxicity as well as how to appropriately treat its complications.

Conflicts over calcium and the treatment of COVID-19

Several recent studies have provided evidence that use of calcium channel blockers (CCBs), especially amlodipine and nifedipine, can reduce mortality from coronavirus disease 2019 (COVID-19). Moreover, hypocalcemia (a reduced level of serum ionized calcium) has been shown to be strongly positively associated with COVID-19 severity. Both effectiveness of CCBs as antiviral therapy, and positive associations of hypocalcemia with mortality, have been demonstrated for many other viruses as well. We evaluate these findings in the contexts of virus–host evolutionary conflicts over calcium metabolism, and hypocalcemia as either pathology, viral manipulation or host defence against pathogens. Considerable evidence supports the hypothesis that hypocalcemia represents a host defence. Indeed, hypocalcemia may exert antiviral effects in a similar manner as do CCBs, through interference with calcium metabolism in virus-infected cells. Prospective clinical studies that address the efficacy of CCBs and hypocalcemia should provide novel insights into the pathogenicity and treatment of COVID-19 and other viruses.

Effects of selective calcium channel blockers on ions' permeation through the human Cav1.2 ion channel: A computational study

Selective calcium channel antagonists are widely used in the treatment of cardiovascular disorders. They are mainly classified into 1,4-dihydropyridine (1,4-DHPs) and non-DHPs. The non-DHPs class is further classified into phenylalkylamines (PAAs) and benzothiazepines (BZTs) derivatives. These blockers are used for the treatment of hypertension, angina pectoris, and cardiac arrhythmias. Despite their well-established efficiency, the structural basis behind their activity is not very clear. Here we report the use of a near-open confirmation (NOC) model of the Cav1.2 cardiac ion channel to examine the mode of binding of these antagonists within the pore domain as well as the fenestration of the pore-forming domains. Effects of calcium ion permeation in the presence of drug molecules were assessed using steered molecular dynamics (SMD) simulations. These studies reveal that nicardipine, a DHP derivative, shows a strong Cav1.2 blocking activity, requiring more 2500 pN force to pull calcium ion towards the channel's pore in the presence of the compound. Similar blocking activity was observed for verapamil, a PAA derivative, requiring almost 2300 pN of force. The least blocking activity was observed for Diltiazem, a BZT derivative. Our results explain the structural basis and the binding details of 1,4-DHPs, PAAs and BZTs at their distinct Cav1.2 sites and offer detailed insights into their mechanism of action in modulating the Cav1.2 channel.

High-Dose Insulin for Toxin Induced Cardiogenic Shock: Experience at a New High and Overview of the Evidence

BACKGROUND

High-dose insulin therapy is an effective treatment for cardiogenic shock caused by the overdose of particular medications. Other treatment options are usually of limited benefit. Consensus suggests that early initiation improves efficacy. No ceiling effect has been established at doses in the general range of 0.5-10 units/kg/hour.

CASE REPORT

A 79-year-old man presented in cardiogenic shock after an intentional overdose of numerous cardioactive medications 10 days after experiencing myocardial infarction. A high-dose insulin infusion was commenced. This was titrated up to a maximum of 20 units/kg/hour (1600 units/hour) and sustained for 32 h (61,334 units total). Minimal adverse events were seen despite this exceptional infusion rate (3 episodes of hypoglycemia and 2 episodes of hypokalemia). Concurrent catecholamine support was used, and cardiovascular function was maintained until all support was withdrawn 5 days after admission. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians are pivotal to the successful initiation/up-titration of high-dose insulin therapy. They must balance the potential for treatment failure with other treatment options, mitigate against adverse events in the initial phase of therapy, and coordinate care between other hospital specialties. This case shows that the relative safety and efficacy was extended to an infusion rate of 20 units/kg/hour, the highest recorded in the published literature. This information may help guide treatment of similar cases in the future.

Severe Amlodipine Toxicity: A Case Rescued with Extracorporeal Membrane Oxygenation

Amlodipine is a widely prescribed drugs for the management of hypertension. Its toxicity is associated with severe myocardial depression and refractory hypotension. We present a case of a 28-year-old female known case of seizure disorder and depression who got admitted to our hospital with a history of consumption of 80 tablets of 5 mg amlodipine (total 400 mg). Patient presented to our hospital after 23 hours following consumption of the drug. Patient was managed in the intensive care unit (ICU) with mechanical ventilation support and intravenous infusion of noradrenalin, adrenalin, insulin-dextrose, and calcium gluconate. Due to refractory hypotension, venoarterial extracorporeal membrane oxygenation (VA-ECMO) was initiated on the same day. Patient was successfully managed and discharged home on the 8th day. This report highlights a rare case of a massive amlodipine overdose (400 mg) and ECMO as a rescue therapy.

How to cite this article

Sutar A, Venkategowda PM, Murthy A, Chikkaswamy SB. Severe Amlodipine Toxicity: A Case Rescued with Extracorporeal Membrane Oxygenation. Indian J Crit Care Med 2020;24(5):365-366.

[Diagnostics and treatment of selected clinically relevant, acute drug intoxications]

Acute drug poisoning due to accidental or self-damaging overdoses is responsible for 5-10% of emergency medical interventions in Germany. The treatment of asymptomatic to life-threatening courses requires extensive expertise. On the basis of a selective literature search, this article gives an overview of selected clinically relevant, acute drug poisonings with regard to epidemiology, symptomatology, diagnostics, and therapy.Intoxications with psychotropic drugs are the most common drug intoxications. Poisoning with tricyclic antidepressants causes anticholinergic, central nervous, and cardiovascular symptoms. Less toxic are selective serotonin reuptake inhibitors (SSRIs); the intoxication may be characterized by serotonin syndrome. Malignant neuroleptic syndrome is a severe complication of neuroleptic poisoning.Poisoning with analgesics is clinically relevant due to its high availability. For paracetamol poisoning, intravenous acetylcysteine is available as an antidote. Hemodialysis may be indicated for severe salicylate intoxication. Poisoning with nonsteroidal anti-inflammatory drugs is usually only associated with mild signs of intoxication.Poisoning with cardiac drugs (β-blockers and calcium antagonists) can cause life-threatening cardiovascular events. In addition to symptomatic therapy, insulin glucose therapy also plays an important role.The majority of acute drug poisonings can be treated adequately by symptomatic and partly intensive care therapy - if necessary with the application of primary and secondary toxin elimination. Depending on the severity of the intoxication, pharmacology-specific therapy must be initiated.

Nifedipine toxicity is exacerbated by acetyl l-carnitine but alleviated by low-dose ketamine in zebrafish in vivo

Calcium channel blocker (CCB) poisoning is a common and sometimes life-threatening emergency. Our previous studies have shown that acetyl l-carnitine (ALCAR) prevents cardiotoxicity and developmental toxicity induced by verapamil, a CCB used to treat patients with hypertension. Here, we tested whether toxicities of nifedipine, a dihydropyridine CCB used to treat hypertension, can also be mitigated by co-treatment with ALCAR. In the zebrafish embryos at three different developmental stages, nifedipine induced developmental toxicity with pericardial sac edema in a dose-dependent manner, which were surprisingly exacerbated with ALCAR co-treatment. Even with low-dose nifedipine (5 μm), when the pericardial sac looked normal, ALCAR co-treatment showed pericardial sac edema. We hypothesized that toxicity by nifedipine, a vasodilator, may be prevented by ketamine, a known vasoconstrictor. Nifedipine toxicity in the embryos was effectively prevented by co-treatment with low (subanesthetic) doses (25-100 μm added to the water) of ketamine, although a high dose of ketamine (2 mm added to the water) partially prevented the toxicity.As expected of a CCB, nifedipine either in the presence or absence of ketamine-reduced metabolic reactive oxygen species (ROS), a downstream product of calcium signaling, in the rapidly developing digestive system. However, nifedipine induced ROS in the trunk region that showed significantly stunted growth indicating that the tissues under stress potentially produced pathologic ROS. To the best of our knowledge, these studies for the first time show that nifedipine and the dietary supplement ALCAR together induce adverse effects while providing evidence on the therapeutic efficacy of subanesthetic doses of ketamine against nifedipine toxicity in vivo.

A randomized controlled trial evaluating the effects of amlodipine on myocardial iron deposition in pediatric patients with thalassemia major

Background

Mortality rates increase due to iron deposition in the cardiac muscles of thalassemia major (TM) patients. Iron overload cardiomyopathy could be treated with a combination therapy of an iron chelator and an L-type calcium channel blocker. We designed a randomized controlled study to assess the potential of amlodipine, alongside chelation, in reducing myocardial iron concentration in TM patients compared with a placebo.

Objectives

This study aims to estimate the change in myocardial iron concentration (MIC) determined by magnetic resonance imaging after 6 months of treatment with amlodipine, as well as measuring the changes in the secondary outcomes (liver iron concentration (LIC), serum ferritin level (SF), and left ventricle ejection fraction (LVEF)) of study participants.

Methods

A single, randomized, placebo-controlled trial was performed in 40 β-Thalassemia major patients aged between 6 and 20 years old, who received either oral amlodipine 2.5–5 mg/day or a placebo, in addition to a Deferasirox chelation regimen in a 1:1 allocation ratio.

Results

After 6 months, a significant reduction was noted in the MIC of patients receiving amlodipine (n=20), compared with the patients receiving the placebo (n=20). At baseline, the mean was 0.76±0.11 mg/g dry weight, while at 6 months, the mean was 0.51±0.07 mg/g dry weight (p<0.001). Also, there was a significant change in the myocardial T2* after 6 months; the amlodipine increased the myocardial T2* from 40.63±5.45 ms at baseline to 43.25±5.35 ms (p<0.001). However, amlodipine did not significantly affect the secondary outcomes by the end of the study.

Conclusion

The addition of amlodipine to the standard chelation therapy in transfusion-dependent thalassemia major patients improves myocardial iron overload without increasing the adverse effects.

Hyponatremia induced by hyperinsulinemia-euglycemia therapy

PURPOSE

A case of symptomatic hyponatremia induced by hyperinsulinemia-euglycemia (HIE) therapy is reported.

SUMMARY

A 59-year-old, 81.65-kg woman with hypertension, major depressive disorder, and anxiety arrived at a tertiary medical center 1.5 hours after an intentional overdose of oral amlodipine 200 mg, metoprolol tartrate 2,000 mg, and isosorbide mononitrate 1,200 mg. Upon arrival, her pulse was 63 beats/min and blood pressure was 106/56 mm Hg. The patient's blood pressure was refractory to fluids, calcium gluconate, and norepinephrine, resulting in initiation of HIE therapy. She had recurrent episodes of hypoglycemia, which required increases of the dextrose infusion and resulted in the patient receiving a total of 6.9 L of dextrose with free water. Seventeen hours into the hospitalization, the patient became obtunded due to hyponatremia (serum sodium concentration, 121 mmol/L). HIE therapy was discontinued, an infusion of 5% dextrose injection with sodium bicarbonate added was started, and a bolus of 3% sodium chloride was administered. Nine hours after the presentation of hyponatremia, the patient's serum sodium concentration normalized (137 mmol/L), and her symptoms resolved. The patient's blood pressure, pulse, and mental status continued to improve, and the patient was transferred out of the medical intensive care unit 41 hours after her arrival at the hospital.

CONCLUSION

A woman who overdosed on amlodipine, metoprolol tartrate, and isosorbide mononitrate was treated with HIE therapy and developed symptomatic hyponatremia. Hyponatremia resolved after administration of dextrose with sodium bicarbonate infusion and 3% sodium chloride infusion and cessation of HIE therapy.

Calcium Channel Blocker Overdose Treated with Calcium Resulting in Pancreatitis: A Case Report

Calcium channel blockers (CCBs) are a mainstay for the treatment of hypertension. Here we report a case of a male who after intentionally ingesting amlodipine presented with overdose symptomology. His QTc (corrected QT) was 525 ms (millisecond) on admission, he was treated with calcium intravenous infusion and subsequently his QTc narrowed to 393 ms, but he also developed iatrogenic pancreatitis. His serum calcium levels were not checked during the infusion. He was treated with supportive care, which led to the normalization of serum calcium levels and a favorable outcome. Further studies are required regarding how frequently calcium levels should be checked during infusions.

Clinical toxicology of beta-blocker overdose in adults

Beta-blocker overdose is potentially harmful due to the strong blood pressure-lowering and heart rate-lowering effects. However, conflicting data exist as to their differential toxicity, single-substance exposures and the effect of co-exposure with additional antihypertensive medication. For this, a 10-year retrospective, explorative analysis of the Mainz Poison Center/Germany database with regard to circumstances of beta-blocker exposure, doses, symptoms and treatment was carried out. Analyses were restricted to adult patients with single-substance exposures and co-exposures with one additional antihypertensive substance. Written follow-up information was obtained in half the cases. A total of 2967 cases were analysed, of which 697 were single-substance exposures. Metoprolol was most frequently reported followed by bisoprolol, atenolol, propranolol and sotalol. Metoprolol showed a linear dose-symptom relationship, whereas propranolol and sotalol seemed to have a threshold dose beyond which symptoms aggravated. Symptoms did not differ substantially, except for more seizures being reported with propranolol, and more CNS depression/vomiting with sotalol. Activated charcoal was used in 38%, gastric lavage in 11%, temporary pacemaker in 3%, glucagon in 1%, intubation for respiratory insufficiency and cardiopulmonary resuscitation in 1% and 0.5%. All patients recovered. In 174 co-exposure cases, the distribution of poisoning severity and rate of worsening of symptoms was comparable with single-substance exposures except one patient deceased after bisoprolol and verapamil co-exposure. In adults with beta-blocker overdose, no significant differences in poisoning severity among beta-blockers were detected, and no fatalities were observed with single-substance exposures. Co-exposures with other antihypertensives, sedatives or alcohol should be carefully attended to as fatalities might occur.

[Acute intoxications: markers for screening, diagnosis and therapy monitoring]

Acute poisonings account for a significant proportion of the patient population presenting to intensive care units, whereby mixed drug overdoses and prescription drug overdoses predominate. The aim of this article was to describe indications for screening, diagnosis and therapy monitoring in acute overdoses in the intensive care unit. To conduct this work, a literature search was carried out and a review was written based on guidelines, case reports, expert opinions and scientific publications. Toxidromes are a useful tool for classification of clinical characteristics when the causative agent is initially unknown. Especially in critical care medicine, identifying and quantifying of the causative toxin by enzyme immunoassays, chromatography and mass spectrometry should be attempted. Intensive care treatment of patients with acute overdoses includes not only monitoring and support of vital functions but also methods for primary and secondary elimination of toxins. The indication for the use of extracorporeal procedures should be carefully evaluated and the method should be chosen based on protein binding and molecular size. Lipid emulsion therapy, high-dose insulin euglycaemia therapy and hyperbaric oxygenation are also increasingly used.

A Case of Life-threatening Amlodipine and Atenolol Overdose

Treating a patient of amlodipine-atenolol poisoning is nightmare for a physician. In high dose both the drugs individually cause severe bradycardia and hypotension. In combination they cause severe cardiovascular depression. Here we report a case of 66-year-old obese, hypertensive, depressed male, who presented to emergency 9 hours after consumption of 25 tablets of amlodipine-atenolol (5 mg+50 mg). On evaluation, he had refractory bradycardia, hypotension and acute kidney injury (AKI). Eventually he developed cardiac arrest. He was revived after 5 minutes of cardio-pulmonary resuscitation (CPR). He was successfully managed with gastric lavage, fluids, inotropes, atropine, isoprenaline and subsequently with calcium gluconate infusion, high-dose insulin euglycemia therapy (HIET) and lipid emulsion therapy. Glucagon infusion was also planned but it was not available. Patient hemodynamics improved and on 8th day he got the discharge. Our case exemplifies the importance of timely and aggressive management of lethal overdose of amlodipine-atenolol poisoning.

How to cite this article: Tale S, Kumar M, Ghosh S, Bhalla A. A Case of Life-threatening Amlodipine and Atenolol Overdose. Indian J Crit Care Med 2019;23(6):281–283.

Unresponsive shock due to amlodipine overdose: An unexpected cause

Amlodipine is a dihydropyridine calcium channel blocker which is widely used as an antihypertensive drug. Amlodipine overdose have been infrequently reported with occurrence of serious complications and even death in a few cases. We report an interesting case of a young lady who presented with refractory shock with acute kidney injury, which did not respond to therapy despite optimal fluid replacement and vasopressor support. The etiology of shock could not be ascertained and the patient was questioned again to elucidate the missing clue in the history. It was finally revealed that the patient had consumed 900 mg of amlodipine in a suicide bid, for her poor performance in academics. The targeted therapy in the form of IV calcium and hyperinsulinemia-euglycemia therapy (HIET) was started and the patient dramatically improved with shock reversal and improvement in renal function.

Does glucagon have a positive inotropic effect in the human heart?

Glucagon is considered to exert cardiostimulant effects, most notably the enhancement of heart rate and contractility, due to the stimulation of glucagon receptors associated with Gs protein stimulation which causes adenylyl cyclase activation and the consequent increase in 3′,5′-cyclic adenosine monophosphate production in the myocardium. These effects have been extensively demonstrated in experimental studies in different animal species. However, efforts to extrapolate the experimental data to patients with low cardiac output states, such as acute heart failure or cardiogenic shock, have been disappointing. The experimental and clinical data on the cardiac effects of glucagon are described here.

Lipid Emulsion Inhibits Apoptosis Induced by a Toxic Dose of Verapamil via the Delta-Opioid Receptor in H9c2 Rat Cardiomyoblasts

The goals of this study were to investigate the effects of lipid emulsion (LE) on apoptosis induced by a toxic dose of verapamil in H9c2 cells and to elucidate the associated cellular mechanism. The effects of LE alone and combined with an inhibitor on the decreases in cell counts and viability induced by verapamil and diltiazem were examined using the MTT assay. The effects of verapamil alone, combined LE and verapamil treatment, and combined inhibitor, LE and verapamil treatment on cleaved caspase-3, caspase-8 and Bax expression, were examined using Western blotting. The effects of verapamil alone and combined with LE on the number of TUNEL-positive H9c2 cells were also examined. LE attenuated the decreases in cell counts and viability induced by verapamil and diltiazem. However, the magnitude of the LE-mediated attenuation of decreased cell viability was enhanced by verapamil compared with diltiazem treatment. Naloxone, naltrindole hydrochloride, LY294002 and MK-2206 inhibited the LE-mediated attenuation of increased cleaved caspase-3 and caspase-8 expression induced by verapamil. LE attenuated the increase in the number of TUNEL-positive cell induced by verapamil. These results suggest that LE attenuates apoptosis induced by verapamil via activation of the delta-opioid receptor, phosphoinositide 3-kinase and Akt.

Critical Management of Severe Hypotension Caused by Amlodipine Toxicity Managed With Hyperinsulinemia/Euglycemia Therapy Supplemented With Calcium Gluconate, Intravenous Glucagon and Other Vasopressor Support: Review of Literature

Calcium channel blocker (CCB ) overdose, whether intentional or accidental, is a common clinical scenario and can be very lethal. Conventional treatments for CCB overdose include intravenous (IV) fluids, calcium salts, dopamine, dobutamine, norepinephrine, phosphodiesterase inhibitors, and glucagon. However, the conventional therapies are unsuccessful in reversing the cardiovascular toxicity of CCB, so they commonly fail to improve the hemodynamic condition of the patient. Blockade of the L-type calcium channels that mediate the antihypertensive effect of CCBs also decreases the release of insulin from pancreatic β-islet cells and reduces glucose uptake by tissues (insulin resistance). By targeting this insulin-mediated pathway, hyperinsulinemia/euglycemia therapy (HIET) appears to have a distinct role, and its clinical potential is underrecognized in the management of severe CCB toxicity. We present a case of young man with amlodipine toxicity successfully managed with high dose of IV insulin therapy.

Extensive Bowel Ischaemia after Nifedipine Overdose

A 57-year-old woman presented with abdominal distension and vomiting two days after overdosing an unknown amount of sustained-release nifedipine tablets. She had refractory shock requiring calcium chloride, glucagon, insulin-glucose and multiple high-dose inotropic agent infusions in the intensive care unit. Her abdominal computed tomography showed features of bowel ischaemia and exploratory laporotomy reviewed non-salvageable massive bowel ischaemia. She finally succumbed after 22 days of hospital treatment. This case illustrates the importance of awareness of this potentially fatal complication of calcium channel blocker overdose, requiring early recognition and intervention.