Amlodipine toxicity in children less than 6 years of age: a dose-response analysis using national poison data system data

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.

Single-Pass Albumin Dialysis as Rescue Therapy for Pediatric Calcium Channel Blocker Overdose

Calcium channel blocker ingestions remain one of the leading causes of death related to cardiovascular medication ingestion in both adults and pediatric patients. We report a case of a 17-year-old, 103 kg female presenting after an intentional polypharmacy ingestion, including 500 to 550 mg of amlodipine. She presented with profound vasoplegia and cardiovascular collapse requiring high-dose inotropes and eventual life support with extracorporeal membrane oxygenation (ECMO). Current available treatments, designed for adults, including lipid emulsion and methylene blue, provided no sustained clinical improvement. This resulted in the initiation of single-pass albumin dialysis (SPAD). We aim to describe the clinical implications, amlodipine toxic dose effects, and clinical challenges associated with large pediatric patients and high-dose medications. We also discuss several challenges encountered related to dosing and concentration of medications, which led to fluid overload. Given the ongoing obesity epidemic, we routinely see pediatric patients of adult size. This will continue to challenge pediatric use of adult dosing and concentrations to avoid excessive fluid administration for high-dose medications, such as insulin and vasoactive agents. To our knowledge, this is the first successful case of using SPAD in conjunction with ECMO for salvage therapy after refractory life-threatening calcium channel blocker toxicity.

Optimization of Personalized Amlodipine Dosing Strategies for Children Based on Pharmacokinetic Data from Chinese Male Adults and PBPK Modeling

For children, a special population who are continuously developing, a reasonable dosing strategy is the key to clinical therapy. Accurate dose predictions can help maximize efficacy and minimize pain in pediatrics. Methods: This study collected amlodipine pharmacokinetics (PK) data from 236 Chinese male adults and established a physiological pharmacokinetic (PBPK) model for adults using GastroPlus™. A PBPK model of pediatrics is constructed based on hepatic-to-body size and enzyme metabolism, used similar to the AUC_0-∞ to deduce the optimal dosage of amlodipine for children aged 1–16 years. A curve of continuous administration for 2-, 6-, 12-, 16-, and 25-year-olds and a personalized administration program for 6-year-olds were developed. Results: The results show that children could not establish uniform allometric amplification rules. The optimal doses were 0.10 mg·kg⁻¹ for ages 2–6 years and −0.0028 × Age + 0.1148 (mg/kg) for ages 7–16 years, r = 0.9941. The trend for continuous administration was consistent among different groups. In a 6-year-old child, a maintenance dose of 2.30 mg was used to increase the initial dose by 2.00 mg and the treatment dose by 1.00 mg to maintain stable plasma concentrations. Conclusions: A PBPK model based on enzyme metabolism can accurately predict the changes in the pharmacokinetic parameters of amlodipine in pediatrics. It can be used to support the optimization of clinical treatment plans in pediatrics.

Extracorporeal treatment for calcium channel blocker poisoning: systematic review and recommendations from the EXTRIP workgroup

BACKGROUND

Calcium channel blockers (CCBs) are commonly used to treat conditions such as arterial hypertension and supraventricular dysrhythmias. Poisoning from these drugs can lead to severe morbidity and mortality. We aimed to determine the utility of extracorporeal treatments (ECTRs) in the management of CCB poisoning.

METHODS

We conducted systematic reviews of the literature, screened studies, extracted data, summarized findings, and formulated recommendations following published EXTRIP methods.

RESULTS

A total of 83 publications (6 in vitro and 1 animal experiments, 55 case reports or case series, 19 pharmacokinetic studies, 1 cohort study and 1 systematic review) met inclusion criteria regarding the effect of ECTR. Toxicokinetic or pharmacokinetic data were available on 210 patients (including 32 for amlodipine, 20 for diltiazem, and 52 for verapamil). Regardless of the ECTR used, amlodipine, bepridil, diltiazem, felodipine, isradipine, mibefradil, nifedipine, nisoldipine, and verapamil were considered not dialyzable, with variable levels of evidence, while no dialyzability grading was possible for nicardipine and nitrendipine. Data were available for clinical analysis on 78 CCB poisoned patients (including 32 patients for amlodipine, 16 for diltiazem, and 23 for verapamil). Standard care (including high dose insulin euglycemic therapy) was not systematically administered. Clinical data did not suggest an improvement in outcomes with ECTR. Consequently, the EXTRIP workgroup recommends against using ECTR in addition to standard care for patients severely poisoned with either amlodipine, diltiazem or verapamil (strong recommendations, very low quality of the evidence (1D)). There were insufficient clinical data to draft recommendation for other CCBs, although the workgroup acknowledged the low dialyzability from, and lack of biological plausibility for, ECTR.

CONCLUSIONS

Both dialyzability and clinical data do not support a clinical benefit from ECTRs for CCB poisoning. The EXTRIP workgroup recommends against using extracorporeal methods to enhance the elimination of amlodipine, diltiazem, and verapamil in patients with severe poisoning.

[Forensic chemical study of Amlodipine]

Is to develop a method for determining amlodipine in the tissues of organs and blood, applicable in the practice of forensic chemical analysis. TLC, normal pressure column chromatography, HPLC and GC-MS were considered as methods of analysis. Amlodipine was isolated from the biomaterial by insisting twice with acetone for 30 min using a 2: 1 mass-isolating and biomatrix agent. The purification of recovered analyte was done in a column (150×10 mm) of a 30 µm Silasorb S-18 sorbent, eluting with an acetone - water solvent mixture (8:2). Preliminary identification was carried out in a thin layer of sorbent on «Sorbfil» plates, which was confirmed by HPLC and GC-MS methods. Determination by GC-MS was carried out in a column with a stationary phase of 5% phenyl-95% dimethylpolysiloxane. The fragmentation of molecules was an electron impact with an energy of 70 eV. Methods for the determination of amlodipine using GC-MS in biomatrix have been developed, which meet the criteria of linearity, selectivity, correctness, precision and stability. The limits of detection and quantitative determination of amlodipine in organ tissues (liver) are 0.14 and 0.24 μg/g, in blood - 0.12 and 0.20 μg/g, respectively. The methods were applied in the examination of a case of amlodipine poisoning and made it possible to determine the analyte in some organs and blood of the corpse.

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

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

Management of Calcium Channel Blocker Toxicity in the Pediatric Patient

Calcium channel blockers (CCBs) are commonly prescribed cardiovascular medications used in several disease states including hypertension, coronary artery disease, and atrial fibrillation. Inadvertent exposure or intentional overdose of CCBs may result in hypotension, bradycardia, dysrhythmias, conduction disturbances, and hyperglycemia. In the most severe cases, CCB toxicity can lead to rapid cardiovascular collapse. Given the risk of significant morbidity and mortality associated with CCB toxicity, it is important that health care professionals are able to recognize and treat patients who present with a potentially toxic ingestion. Due to the paucity of literature in managing pediatric patients with severe CCB toxicity, treatment strategies for pediatric patients are mostly limited to case reports and extrapolation from expert consensus recommendations for adults. All pediatric patients with a potentially toxic CCB ingestion should be evaluated in the emergency department. Activated charcoal may be considered for asymptomatic patients presenting within an hour of ingestion. Symptomatic patients should be placed under cardiac monitoring and treatments to stabilize the patient's hemodynamics should not be delayed. Traditional first-line IV therapies include small boluses of fluids, calcium, and vasopressors. High-dose insulin has been proposed to independently increase inotropy and improve CCB-induced hypoinsulinemia and insulin resistance that results from CCB inhibition of insulin release from pancreatic β-islet cells. High-dose insulin is recommended as first-line therapy for adults and shows promising efficacy and safety in several pediatric case reports. Intravenous lipid emulsion may be considered in patients who are refractory to first-line therapies, although the data for pediatric patients are extremely limited.

Outcomes following calcium channel blocker exposures reported to a poison information center

Background

Calcium channel blockers (CCBs) are widely used drugs that have a narrow therapeutic index. Even minor overdoses must be treated in-hospital due to the risk of severe hypotension and bradycardia. We aimed to describe trends in CCB use and overdoses in Denmark.

Methods

Data on enquiries concerning CCBs reported to the Danish Poisons Information Center (DPIC) from January 2009 to January 2015 was coupled with data on hospitalization and mortality obtained from Danish National Registers. We obtained data on the general use of CCBs in Denmark and retrieved medical charts on fatal cases.

Results

From a total of 126,987 enquiries to the DPIC in 2009–2014 we identified 339 CCB unique exposures (3‰ of all). Children < 5 years accounted for 20% all exposures and these were classified as ‘intake during playing’ (61%) and ‘medication errors’ (39%). Among adults ‘suicidal poisonings’ (58%), and ‘medication errors’ (34%) were most frequent. A majority (81%) of exposures led to hospital admission. Seven patients (2%) died from the CCB exposure and all were adults with ‘suicidal poisoning’. Amlodipine accounted for 95% of all CCB prescriptions, was involved in 71% of enquiries and in 29% of fatalities. Verapamil accounted for 3% of prescriptions, was involved in 13% of enquiries and 57% of fatalities.

Conclusion

Four fifths of enquiries to the DPIC result in hospitalization and one fifth concern small children. Mortality were infrequent and occurred only in adults with suicidal exposures and with and an overrepresentation of verapamil exposures.

Recurrent episodes of life-threatening vasodilatory shock following unintentional intoxication with amlodipine

Calcium channel blockers (CCBs) have a narrow therapeutic index, and their intake in excess is associated with a critical clinical presentation of sustained hypotension and non-cardiogenic pulmonary edema, which are difficult to treat. Unfortunately, the available treatments fail to resuscitate a significant number of patients poisoned by CCBs, rendering them the main cardiovascular drugs involved in death due to overdose. Importantly, in all cases reported until now in the literature, CCB intoxication was known at the time of patients' presentation and the medical challenge solely consisted of the therapeutic approach. In this case report, we describe our experience in treating a 72-year-old patient with recurrent episodes of sustained hypotension refractory to crystalloid and vasoconstrictor infusions. Prolonged pharmacologic support and intermittent sessions of hemofiltration induced stabilization and recovery. The results of an extensive diagnostic workup to elucidate the cause were unfruitful. The recurrent and paroxysmal nature of the clinical presentation along with its incidence after the patient left the protected setting of the hospital led the diagnostic approach to search for a possible external factor, which was shown to be, after toxicological investigation, unintentional amlodipine intoxication.

Calcium channel antagonist and beta-blocker overdose: antidotes and adjunct therapies

Management of cardiovascular instability resulting from calcium channel antagonist (CCB) or beta-adrenergic receptor antagonist (BB) poisoning follows similar principles. Significant myocardial depression, bradycardia and hypotension result in both cases. CCBs can also produce vasodilatory shock. Additionally, CCBs, such as verapamil and diltiazem, are commonly ingested in sustained-release formulations. This can also be the case for some BBs. Peak toxicity can be delayed by several hours. Provision of early gastrointestinal decontamination with activated charcoal and whole-bowel irrigation might mitigate this. Treatment of shock requires a multimodal approach to inotropic therapy that can be guided by echocardiographic or invasive haemodynamic assessment of myocardial function. High-dose insulin euglycaemia is commonly recommended as a first-line treatment in these poisonings, to improve myocardial contractility, and should be instituted early when myocardial dysfunction is suspected. Catecholamine infusions are complementary to this therapy for both inotropic and chronotropic support. Catecholamine vasopressors and vasopressin are used in the treatment of vasodilatory shock. Optimizing serum calcium concentration can confer some benefit to improving myocardial function and vascular tone after CCB poisoning. High-dose glucagon infusions have provided moderate chronotropic and inotropic benefits in BB poisoning. Phosphodiesterase inhibitors and levosimendan have positive inotropic effects but also produce peripheral vasodilation, which can limit blood pressure improvement. In cases of severe cardiogenic shock and/or cardiac arrest post-poisoning, extracorporeal cardiac assist devices have resulted in successful recovery. Other treatments used in refractory hypotension include intravenous lipid emulsion for lipophilic CCB and BB poisoning and methylene blue for refractory vasodilatory shock.

Toxicity of antihypertensives in unintentional poisoning of young children

BACKGROUND

Knowledge is limited about the toxicity of unintentional exposure to antihypertensives in young children (0-6 years of age).

OBJECTIVE

Our aim was to research symptoms and poisoning severity in unintentional poisonings in this group of age and determine adequate poisoning management.

METHODS

We performed a 10-year retrospective, explorative analysis of the Mainz Poison Center/Germany database with regard to circumstances of poison exposure, dosage, symptoms, and treatment. To be able to relate drug exposure with reported symptoms, analyses were restricted to single drug exposures. Written follow-up information was obtained in about 50% of all cases.

RESULTS

A total of 1489 cases were analyzed, of which 957 were single drug exposures with 421 exposures to beta-blocking agents, 364 to inhibitors of the renin-angiotensin system, 122 to calcium channel blockers, and 50 to antiadrenergic drugs. No severe (Poisoning Severity Score [PSS]=3) or fatal poisonings (PSS=4) were reported and, with the exception of atenolol, propranolol, irbesartan, isradipin, clonidine, and moxonidine, no poisonings with a PSS>1. We did not find a significant relationship between dosage, release formulation and symptoms, or PSS. All patients fully recovered without specific treatment.

CONCLUSIONS

In young children with unintentional, single drug exposure to the most popular antihypertensive medication (i.e., metoprolol, bisoprolol, ramipril, enalapril, lisinopril, captopril, candesartan, valsartan, amlodipine, and verapamil), only mild symptoms occurred, and hospital evaluation is not a must. However, children with recent exposure to clonidine or moxonidine should be evaluated at a hospital due to an increased likelihood of poisonings of at least moderate severity.

Near fatal case of amlodipine poisoning in an infant

An 11-mo-old infant received 12.5 times the maximum therapeutic dose of amlodipine as a result of a medication error in lieu of amoxicillin. He presented with vomiting, lethargy, breathlessness, muffled heart sounds and progressed to hypotensive shock within three hours of admission. He received mechanical ventilation, fluid therapy with normal saline and inotropes. But his parameters improved rapidly only after initiating him on insulin and dextrose infusion therapy (for 15 h) along with glucagon and calcium gluconate infusion (for 72 h). Calcium channel blockers (CCB) cause impaired insulin secretion causing hyperglycemia. High levels of blood sugar are of prognostic value rather than hemodynamic variables in CCB poisoning. A continuous infusion of 0.5 to 1 unit per kg body weight per hour of insulin along with supportive therapy including peritoneal dialysis (for deranged renal function) was used with success in managing amlodipine poisoning.

Amlodipine fatality in an infant with postmortem blood levels

INTRODUCTION

Amlodipine is a dihydropyridine calcium channel blocker used in the treatment of hypertension and angina pectoris. Toxic effects reported from amlodipine include hypotension, reflex tachycardia, metabolic acidosis, and pulmonary edema. We report a rare fatality in an infant after ingestion of amlodipine with benazepril, with postmortem blood concentrations.

CASE REPORT

An 11-month-old, 10.88-kg boy ingested 10 to 45 mg amlodipine with 40 to 180 mg benazepril. No action was taken initially because the parents believed only one or two capsules had been ingested. A later count revealed a maximum of nine capsules missing. The child was observed at home and vomited once with possible capsule fragments. Forty-five minutes post-ingestion, the child was noted to be suddenly unresponsive and was brought the local emergency department by a private vehicle. Upon arrival (90 min post-ingestion), the child was unresponsive with the following vital signs HR 133 bpm, BP 67/42 mmHg, respiratory rate 40/min, and temperature 97.5°F. Pertinent abnormal laboratory values were HCO(3) 13 mmol/l and glucose 302 mg/dl. The child was placed on oxygen via a non-rebreather mask and was intubated 45 min post-arrival. The patient became progressively bradycardic, and 55 min after arrival, the patient was in asystole with no palpable blood pressure. Resuscitation measures included chest compressions, epinephrine atropine, sodium bicarbonate, and calcium gluconate. Rescue insulin therapy was begun with 4 units IVP followed by 10 units per hour. Resuscitation efforts persisted for 1 h without success. An autopsy revealed pulmonary edema and no gross or microscopic evidence of natural disease. Stomach contents revealed food matter with small white fragments. Analysis of postmortem heart blood showed amlodipine 1,300 ng/ml (therapeutic <20 ng/ml). Benazepril levels were not available.

DISCUSSION

We believe this is the first reported fatality in an infant from amlodipine. While benazepril may have contributed, ACE inhibitors have not been previously associated with rapid cardiovascular collapse.

CONCLUSION

Small doses of amlodipine (0.9 to 4.1 mg/kg) may produce rapid and fatal cardiovascular collapse in an infant.