Management of calcium channel blocker overdoses

Endotracheal Intubation in the Pharmaceutical-Poisoned Patient: a Narrative Review of the Literature

INTRODUCTION

Endotracheal intubation (ETI) is an essential component of the supportive care provided to the critically ill patient with pharmaceutical poisoning; however, specific nuances surrounding intubation including techniques and complications in the context of pharmaceutical poisoning have not been well elucidated.

DISCUSSION

A search of the available literature on ETI in pharmaceutical-poisoned patients was undertaken using Medline, ERIC, Cochrane database, and PsycINFO using the following MeSH and keyword terms: ("toxicology" OR "poisons" OR "drug overdose" OR "poisoning") AND ("intubation, intratracheal" OR "intubation, endotracheal" OR "airway management" OR "respiration, artificial"). A hand-search was also performed when the literature in the above search required additional conceptual clarification, including using the "Similar Articles" feature of PubMed, along with reviewing articles' reference lists that discussed intubation in the context of a poisoning scenario. Articles with any discussion around the ETI process in the context of a pharmaceutical poisoning were then included. Intubation may be performed in patients poisoned with pharmaceuticals in the context of both single and multiple organ dysfunction including central and peripheral nervous system, pulmonary, or cardiovascular toxicity with hemodynamic instability, or localized effects resulting in mechanical airway obstruction. Certain classes of poisonings may require modifications to the standard rapid sequence induction airway management algorithm.

CONCLUSIONS

ETI is a key component of the supportive care provided to the patient poisoned by a pharmaceutical agent. Clinicians should be aware of the spectrum of toxicities that can necessitate intubation, as well as airway management nuances that are specific to various poisoning presentations.

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.

Comparative effectiveness of methylene blue versus intravenous lipid emulsion in a rodent model of amlodipine toxicity

Context: Calcium channel blocker (CCB) poisonings are the leading cause of death from cardiovascular medication-related overdoses. Current treatments (calcium salts, vasopressors, inotropes) are often insufficient. Intravenous lipid emulsion (ILE) and methylene blue (MB) show promise in treating CCB overdoses unresponsive to conventional therapy. Objective: To compare the effectiveness of MB versus ILE in a rodent model of amlodipine (AML) poisoning with survival as the primary outcome and hemodynamic parameters as secondary outcomes. Materials and methods: Sixty-four adult male albino rats were anesthetized and cannulated for non-invasive hemodynamic measurement. Rats received amlodipine intraperitoneally (42 mg/kg). We then divided the rats into four groups: AML only without antidote, AML followed by ILE (24.8 mL/kg over 10 min), AML followed by normal saline (an equivalent volume of ILE), and AML followed by IV MB (2 mg/kg over 5 min). They received study treatments at 5, 30, and 60 minutes from the start of the protocol and with observation for 2 hours. Results: Survival time in ILE group was greater than in the control and NS groups. Differences between ILE and MB and between MB and NS were not significant. Hemodynamic parameters significantly increased in ILE group compared to the MB group at the 30, 60 and 120 min assessments but not after induction of AML poisoning and at 5 min assessment. Conclusions: Survival was greatest in rats treated with ILE. Both MB and NS had little effect on survival when compared to control animals. Both ILE and MB improved hemodynamics.

A Fatal Case of Amlodipine Toxicity Following Iatrogenic Hypercalcemia

Using calcium salts in management of amlodipine overdose is challenging. A 25-year-old male with known history of adult polycystic kidney disease presented with hypotension, tachycardia, and intact neurological status after ingestion of 450 mg of amlodipine. Immediately, normal saline infusion and norepinephrine were initiated. Two grams of calcium gluconate was injected, followed by intravenous infusion of 1.16 mg/kg/h. The patient was put on insulin-glucose protocol to maintain euglycemia and hyperinsulinemia. Electrocardiography demonstrated junctional rhythm. Serum creatinine was 2.5 mg/dL with metabolic acidosis. By the end of 24 h post-admission, his consciousness, blood pressure, and urine output were normal. Almost 32 h post-admission, he became disoriented and his oxygen saturation decreased and therefore was mechanically ventilated. Second chest X-ray showed pulmonary edema. Serum calcium level increased to 26.1 mg/dL. Calcium was discontinued, and furosemide infusion and calcitonin were intravenously administrated. Urine output increased and hemodialysis improved pulmonary edema and serum calcium level with no change in consciousness. Three days after admission, the patient became anuric and developed multi-organ failure and died 5 days post-admission. To avoid the consequences of excessive infusion of calcium in renal failure patients, the minimum calcium dose with close monitoring is recommended.

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.

Scientific research related to calcium channel blockers poisoning: Bibliometric analysis in Scopus, 1968-2012

PURPOSE

Calcium channel blockers (CCBs) were the most common agents associated with a significant morbidity and mortality rate. The main objective of this study was to examine the publication pattern related to CCBs poisoning at the global level using bibliometric analysis of articles published in SciVerse Scopus online database.

METHODS

Data were searched for documents that contained specific words regarding CCB poisoning as keywords in the title. No time period limitations were specified in the search regarding the starting year. The ending date of the search was 31 December 2012.

RESULTS

The criteria were met by 713 publications from 53 countries. The largest number of articles associated with CCBs was from the United States (30%), followed by the United Kingdom (7.4%), Japan (6%), and Germany (5.6%). No data related to CCBs were published from 159 (75%) of 212 countries registered in World Bank online database. There was no correlation between the number of published articles in the country and its population size (r = 0.03, p > 0.926). United Kingdom and Australia were the leading countries in terms of number of CCBs publications per million inhabitants (0.83 and 0.82 articles per million inhabitants, respectively), followed by the United States (0.68). Countries with a large population, such as India, tended to rank relatively low (0.01 articles per million inhabitants). The total number of citations at the time of data analysis (23 October 2014) was 6462, with an average of 9.1 citations per document. The highest median (interquartile range) number of citations was 8 (8-18) for the United States, followed by 6 (1-21) for Australia, 5 (1-15) for the United Kingdom, and 5 (1-24) for Canada. The h-index of the retrieved documents was 37.

CONCLUSIONS

Scientific production on CCBs poisoning is increasing; nonetheless, the international collaboration is still rare. The amount of CCBs-based research activity was low or not available in most countries. More regional epidemiological studies are required to bridge the gap in CCBs-based research and to promote better evaluation of CCBs poisoning worldwide.