Mixed amlodipine/valsartan overdose treated by the molecular adsorbent recirculating system (MARS™)

Angiotensin II Use in Treatment of Refractory Shock Due to Benazepril and Amlodipine Toxic Ingestion

Introduction: Calcium channel blockers (CCB) are a leading cause of ingestion-associated fatality. Angiotensin-converting enzyme inhibitor (ACEi) overdose as part of co-ingestion is common and associated with refractory shock. Treatment options to manage this profound vasoplegia are limited. We describe the first case of use of newly formulated Angiotensin II for treatment of severe ACEi and CCB poisoning. Case Report: A 57-year-old man presented after suicide attempt by ingesting 20 tablets each of amlodipine 10 mg and benazepril 20 mg. His hypotension was initially managed with 35 mL/kg of crystalloid, norepinephrine, and hyperinsulinemic euglycemic therapy (HIET). His hemodynamics further deteriorated, and he developed lactic acidosis, electrolyte derangements, and renal dysfunction. Further complications of his ingestion included cardiac arrest, subsequent requirement for emergency cricothyrotomy, and renal replacement therapy. Maximal hemodynamic support with HIET therapy insulin drip 4.4 units/kg/hour, norepinephrine 2 mcg/kg/min, epinephrine 1 mcg/kg/min, vasopressin .06 units/hour, and intravenous lipid emulsion was unsuccessful. Ang II was started and titrated to maximal doses with dramatic improvement in hemodynamics. Within hours of starting Ang II, epinephrine was stopped and norepinephrine decreased by 50%. He was downgraded from the intensive care unit without any ongoing end-organ dysfunction. Discussion: Isolated CCB overdoses have high complication rates and well-established treatments. Therefore, management of CCB and ACEi co-ingestion is typically driven by CCB poisoning algorithm. There are multiple reports of CCB and ACEi co-ingestions causing treatment-refractory shock. Therapeutic options are limited by toxicities and availability of salvage therapies. Ang II is a safe and highly effective option to manage these patients.

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.

Amlodipine Overdose: Is High Dose Insulin Ready for Prime Time

Overdose of amlodipine, a dihydropyridine calcium channel blocker (CCB), is distinguished from other CCBs due to longer plasma half-life of 30 to 58 h. As current management strategies of CCB overdose are diverse and institution dependent, this retrospective observational study aimed to compare treatment and outcomes data extracted from published case reports of amlodipine overdose with a cohort of patients diagnosed with amlodipine overdose at an urban tertiary medical center. Particular attention was paid to the use of high dose insulin euglycemic therapy (HIET) in treatment of amlodipine overdose. Data was extracted from actual adult patients hospitalized for amlodipine overdose at an urban tertiary medical center up to 2018, and from case reports of amlodipine overdose published between 1997 and 2020. We found a tendency towards earlier and more frequent initiation of HIET over time in management of amlodipine overdose, facilitating hospital discharge. Given the lack of randomized controlled trials comparing vasopressors, HIET, or other therapies, optimal treatment for amlodipine overdose has yet to be definitively established. Based on currently available evidence, a reasonable approach to management of the hemodynamically unstable patient presenting with amlodipine overdose includes vasopressors and inotropes with earlier initiation of HIET.

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.

Hemodynamic impact of molecular adsorbent recirculating system in refractory vasoplegic shock due to calcium channel blocker poisoning

OBJECTIVE

To report the hemodynamic effect of to the molecular adsorbent recirculating system (MARS™) therapy for patients in refractory vasoplegic shock due to calcium channel blocker (CCB) poisoning.

METHODS

We report a retrospective cohort of patients who were hospitalized for CCB poisoning with refractory vasoplegic shock and treated by MARS therapy, at Amiens Hospital University, from January 2010 to December 2019. Improvement in hemodynamic was assessed by dynamic changes in mean arterial pressure (MAP) and norepinephrine levels over a 24-h period after MARS therapy. Cardiac function was assessed by transthoracic echocardiography.

RESULTS

MARS therapy was performed on seven patients for CCB poisoning. CCB poisoning included nicardipine (n = 3, 43%) amlodipine (n = 3, 43%), and verapamil (n = 1, 14%). The median time to start MARS therapy was 24 [14-27] h after drug ingestion and 6 [2-9] h after ICU admission. Cardiac output was preserved for all patients. MAP values improved from 56 [43-58] to 65 [61-78] 16 mmHg (p = 0.005). Norepinephrine dose significantly decreased from 3.2 [0.8-10] µg/kg/min to 1.2 [0.1-1.9] µg/kg/min (p = 0.008) and lactate level decreased from 3.2 [2.4-3.4] mmol/l^-1 to 1.6 [0.9-2.2] mmol/l^-1 (p = 0.008). The median length of ICU stay was 4 (2-7) days and hospital stay was 4 (4-16) days. No complication related to the MARS therapy were reported. No patient died and all were discharged from the hospital.

CONCLUSION

We reported the largest case-series of MARS therapy for refractory vasoplegic shock due to CCB poisoning. We observed that MARS therapy was associated with an improvement of hemodynamic parameters.

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.

Angiotensin axis antagonists increase the incidence of haemodynamic instability in dihydropyridine calcium channel blocker poisoning

CONTEXT

Amlodipine, a dihydropyridine calcium channel blocker (CCB), is the leading cause of cardiovascular drug-related overdose deaths in the USA. In contrast, angiotensin-II receptor blockers (ARBs) and angiotensin converting enzyme inhibitors (ACEIs) cause minimal toxicity in overdose. ACEIs/ARBs are often combined with dihydropyridines in hypertension treatment. Co-ingested ARBs/ACEIs may significantly contribute to the toxicity of dihydropyridine, but this has not been investigated.

OBJECTIVE

To investigate the clinical outcomes from dihydropyridine overdoses with ARBs/ACEIs versus dihydropyridine overdoses alone.

METHODS

This was a retrospective study of patients reported to the New South Wales Poisons Information Centre (NSW PIC) and 3 toxicology units (Jan 2016 to Jun 2019) in Australia. Patients >14 years who took an overdose of dihydropyridines (amlodipine, felodipine, lercanidipine, nifedipine) were included. Concurrent overdoses with non-dihydropyridine CCBs, alpha-blockers and beta-blockers were excluded. Patient demographics, drugs exposure details, serial vital signs, treatments and outcome were collected.

RESULTS

There were 100 patients. 68 took mixed overdoses of dihydropyridines with ARBs/ACEIs and 32 took single overdoses of dihydropyridines without ARBs/ACEIs. The mixed group had lower median nadir mean arterial pressures (62 vs 75 mmHg, p < 0.001), more frequently had hypotension (OR 4.5, 95%CI: 1.7-11.9) or bradycardia (OR 8.8, 95%CI: 1.1-70). Multivariable analysis indicated the mixed overdoses had an 11.5 mmHg (95%CI: 4.9-18.1) lower minimum systolic blood pressure (SBP) compared with the single group; other factors associated with a lower minimum SBP were higher doses [2.3 mmHg (95%CI: 1.1-3.5) lower per 10 defined daily doses] and younger age [2.2 mmHg (95%CI: 0.3-4.2) higher per decade]. A larger proportion of the mixed ingestion group received intravenous fluids (OR 5.7, 95%CI: 1.8-18.6) and antidotes and/or vasopressors (OR 2.9, 95%CI: 1.004-8.6).

CONCLUSION

Combined overdoses of dihydropyridines with ARBs/ACEIs caused more significant hypotension and required more haemodynamic support than overdoses of dihydropyridines alone.

The Efficacy of Albumin Dialysis in the Reversal of Refractory Vasoplegic Shock Due to Amlodipine Toxicity

Objectives:

Calcium channel blockers are highly protein-bound medications frequently used in the management of hypertension. Overdose results in severe hypotension and is the fourth most common cause of toxicity-related deaths in the United States. Management is mostly supportive, with currently no standard role for targeted drug removal. The protein-bound nature of these medications presents the option of utilizing albumin dialysis for their removal and for the reversal of associated shock.

Design and Subjects:

We present two cases of life-threatening intentional amlodipine overdoses successfully treated with albumin dialysis. Both patients experienced profound distributive shock in the setting of preserved cardiac contractility that was refractory to maximal vasoactive agent support.

Interventions and Results:

After initiation of albumin dialysis, the patients showed rapid hemodynamic improvement and were able to be weaned off vasopressor support.

Conclusions:

These cases demonstrate the safety and efficacy of albumin dialysis in the management of near-fatal calcium channel blocker overdoses related to amlodipine and offer an additional therapeutic option apart from conventional supportive care. Importantly, these cases were not associated with impaired cardiac contractility, thereby making venoarterial extracorporeal membrane oxygenation a less preferable option. Furthermore, this therapeutic benefit of albumin dialysis can potentially be extended to the management of toxicity related to other highly protein-bound drugs and toxins.

Clinical utility of midodrine and methylene blue as catecholamine-sparing agents in intensive care unit patients with shock

Shock is common in the intensive care unit, affecting up to one third of patients. Treatment of shock is centered upon managing hypotension and ensuring adequate perfusion via administration of fluids and catecholamine vasopressors. Due to the risks associated with catecholamine vasopressors, interest has grown in using catecholamine-sparing agents such as midodrine and methylene blue. Midodrine is an orally administered alpha-1 adrenergic agonist while methylene blue is an intravenously administered blue dye used to restore vascular tone and increase blood pressure. Separate MEDLINE, Scopus, and Embase database searches were conducted to assess literature revolving around these agents. Examples of search terms included "midodrine", "methylene blue", "critically ill", "shock", and "catecholamine-sparing." Several studies have evaluated their use in patients with shock and found potential benefits in terms of causing significant elevations in blood pressure and hastening catecholamine vasopressor discontinuation with few adverse effects; however, robust evidence is lacking for these off-label indications. Because of the variety of dosing strategies used and the incongruences between patient populations, it is also challenging to define finite recommendations. This review aims to summarize current evidence for the use of midodrine and methylene blue as catecholamine-sparing agents in critically ill patients with resolving or refractory shock.

Development and Feasibility of a Porcine Model of Amlodipine Toxicity

INTRODUCTION

Toxicity related to calcium-channel blockers remains a significant cause of morbidity and mortality. Amlodipine-induced shock is unique in that its mechanism of action is thought to occur in part via the release of nitric oxide (NO) in the peripheral vasculature. Specific therapeutic interventions, including methylene blue (an NO scavenger), have been suggested, but efficacy studies are severely limited. To facilitate a larger porcine study into the effect of various interventions on amlodipine toxicity, we undertook this model development and feasibility study.

METHODS

Intravenous amlodipine was prepared by dissolving commercially obtained amlodipine tablets in dimethylsulfoxide. The concentration of the drug was verified using ultraviolet spectroscopy. We administered this solution to three animals in order to determine a toxic dose, capable of facilitating a two-arm study of amlodipine toxicity.

RESULTS

The first pig died rapidly after the bolus infusion. The second pig developed mild toxicity, but the dissolution of the plastic tubing by the solvent and subsequent leakage limited the interpretability of the result. The third animal developed expected toxicity with an infusion rate between 2.0  and 5.5 mg/kg/h.

CONCLUSION

This study demonstrates a potentially repeatable model of amlodipine-induced toxic shock using intravenous administration of amlodipine and several methodological considerations for researchers undertaking similar work.

Literature review of the evidence regarding intravenous lipid administration in drug-induced cardiotoxicity

Introduction: Intravenous lipid emulsion (ILE) administration is capable of reversing the acute cardiac and neurological toxicity caused by local anesthetic agents. In recent years, ILE has also been explored as a potential antidote for cardiotoxicity caused by non-anesthetic agents too. Areas covered: The potential mechanisms, safety, and efficacy of this approach are considered. Data were sought from published reports listed in PubMed and EMBASE, and abstracts of meetings of the North American Congress of Clinical Toxicology and European Association of Poisons Centres and Clinical Toxicologists. There were reports involving 298 patients where ILE has been administered for severe drug toxicity. Clinical improvement was observed in 57 of 59 patients with local anesthetic toxicity (96.6%); there were 239 patients where toxicity was due to non-anesthetic agents, and ILE apparently improved clinical outcome in 215 (72.1%). Expert opinion: Response rates were similar between ILE treated toxicity caused by lipid soluble and non-lipid soluble drugs. Potential adverse effects of ILE include interference with laboratory assays, acute pancreatitis, and adult respiratory distress syndrome, although the rate of occurrence is difficult to ascertain.

Two Fatal Cases Involving Cardiovascular Drugs Diltiazem and Amlodipine

A liquid chromatographic tandem mass spectrometric method for the identification and quantification of 18 cardiovascular drugs was developed in order to evaluate two cases of fatal intoxication involving diltiazem and amlodipine respectively. Samples were simply diluted and centrifuged using a three-steps procedure with methanol, acetonitrile and mobile phase. The method proved to be selective and all the validation parameters fulfilled the acceptance criteria. In particular, linearity was studied in the range limits of quantitation (LOQ)-1,000 ng/mL (LOQ ranging from 0.8 to 33.3 ng/mL for urine and from 0.7 to 41.3 ng/mL for whole blood). The method was successfully applied to two real cases involving diltiazem and amlodipine fatal intoxications, respectively. Though the subject intoxicated by diltiazem did survive several hours after drug intake, central and peripheral blood levels at autopsy were extremely high (23.4 and 13.4 mg/L, respectively); the cause could be due to the formation of a pharmacobezoar that was found in the duodenum and that could have delayed the drug absorption. Moreover, diltiazem showed postmortem redistribution. On the contrary, the amlodipine peripheral blood level in the second case was relatively low (0.17 mg/L), thus confirming that even the uncontrolled intake of a less toxic calcium channel blocker can lead to death. Furthermore, blood samples were analyzed after 2 years of storage at -20°C: both diltiazem and amlodipine showed a significant degradation (70 and 99%, respectively).

Experts Consensus Recommendations for the Management of Calcium Channel Blocker Poisoning in Adults

OBJECTIVE

To provide a management approach for adults with calcium channel blocker poisoning.

DATA SOURCES, STUDY SELECTION, AND DATA EXTRACTION

Following the Appraisal of Guidelines for Research & Evaluation II instrument, initial voting statements were constructed based on summaries outlining the evidence, risks, and benefits.

DATA SYNTHESIS

We recommend 1) for asymptomatic patients, observation and consideration of decontamination following a potentially toxic calcium channel blocker ingestion (1D); 2) as first-line therapies (prioritized based on desired effect), IV calcium (1D), high-dose insulin therapy (1D-2D), and norepinephrine and/or epinephrine (1D). We also suggest dobutamine or epinephrine in the presence of cardiogenic shock (2D) and atropine in the presence of symptomatic bradycardia or conduction disturbance (2D); 3) in patients refractory to the first-line treatments, we suggest incremental doses of high-dose insulin therapy if myocardial dysfunction is present (2D), IV lipid-emulsion therapy (2D), and using a pacemaker in the presence of unstable bradycardia or high-grade arteriovenous block without significant alteration in cardiac inotropism (2D); 4) in patients with refractory shock or who are periarrest, we recommend incremental doses of high-dose insulin (1D) and IV lipid-emulsion therapy (1D) if not already tried. We suggest venoarterial extracorporeal membrane oxygenation, if available, when refractory shock has a significant cardiogenic component (2D), and using pacemaker in the presence of unstable bradycardia or high-grade arteriovenous block in the absence of myocardial dysfunction (2D) if not already tried; 5) in patients with cardiac arrest, we recommend IV calcium in addition to the standard advanced cardiac life-support (1D), lipid-emulsion therapy (1D), and we suggest venoarterial extracorporeal membrane oxygenation if available (2D).

CONCLUSION

We offer recommendations for the stepwise management of calcium channel blocker toxicity. For all interventions, the level of evidence was very low.