The role of insulin and glucose (hyperinsulinaemia/euglycaemia) therapy in acute calcium channel antagonist and beta-blocker poisoning

Beta-blocker and calcium-channel blocker toxicity: current evidence on evaluation and management

Beta-blocker and calcium-channel blocker overdoses are associated with severe morbidity and mortality; therefore, it is important to recognize and appropriately treat individuals with toxicity. The most common clinical findings in toxicity are bradycardia and hypotension. In addition to supportive care and cardiac monitoring, specific treatment includes administration of calcium salts, vasopressors, and high-dose insulin euglycaemia treatment. Other advanced treatments (e.g. ECMO) may be indicated depending on the severity of toxicity and specific agents involved.

Refractory Shock from Amlodipine Overdose Overcomed with Hyperinsulinemia

Intoxication from calcium channel blockers exhibits almost 50% mortality rates. Amlodipine is a long-acting dihydropyridine and inappropriate dosage poses a great threat for profound vasodilation, hypotension, and refractory vasopressor-resistant shock. A 72-year-old woman with unremarkable medical history presented to the emergency department due to amlodipine overdose after a suicide attempt attributed to COVID-19 pandemic severe anxiety disorder. Vital signs at presentation: heart rate 82 beats/ min, arterial pressure 72/55 mmHg, and oxygen saturation 98%. Resuscitation was initiated with intravenous infusion of normal saline 0,9%, noradrenaline, and calcium chloride, while activated charcoal was orally administrated; however, blood pressure remained at 70/45 mmHg. Abruptly, she experienced acute pulmonary edema and was finally intubated. We commenced high-dose insulin infusion with Dextrose 10% infusion to maintain euglycemic hyperinsulinemia. Hemodynamic improvement occurred after 30 min, systolic blood pressure raised to 95 mmHg, and decongestion was achieved with intravenous furosemide. Insulin effect was dose-dependent and patient’s hemodynamic status improved after insulin uptitration. Eight days later, the patient was weaned from the mechanical ventilation and she was successfully discharged after 14 days. High-dose intravenous infusion of insulin up to 10 units/kg per hour appears as an inotropic agent possibly through alterations in myocardial metabolism of fatty acids and augmentation of insulin secretion and uptake. This regimen possibly exhibits additional vasotropic properties. We conclude that euglycemic hyperinsulinemia is a potentially advantageous treatment in CCB toxicity.

Metformin poisoning treated with high dose insulin dextrose therapy: a case series

Purpose

We describe the compassionate use of high dose insulin dextrose (HID) for life threatening metformin associated lactic acidosis (MALA) in four patients admitted to intensive care.

Methods

Patients presenting with refractory lactic acidosis believed to be secondary to metformin poisoning were included.High dose insulin dextrose at 0.5units/kg/hour was infused in 50% dextrose. Frequent blood gas analysis allowed titration of therapy. All patients also received continuous veno-venous haemofiltration.

Results

All four patients recovered to normal or near normal lactate and pH between 10 and 24 hours of therapy. Two patients had significant separation in time between initiation of HID and haemofiltration to suggest an independent effect of HID on improving pH and lactate.All patients had at least one episode of hypoglycaemia below 4.0 mmol/L with the lowest glucose in any patient during therapy being 3.0 mmol/L. All episodes were corrected with a dextrose infusion without sequelae.

Conclusions

Our study demonstrates that HID therapy appears to be safe in patients with suspected metformin poisoning. It also appears to work to drive down lactate, improve pH and patients' clinical condition. Further evidence is required to assess the effectiveness of HID therapy in the context of MALA.

A randomized controlled study comparing high-dose insulin to vasopressors or combination therapy in a porcine model of refractory propranolol-induced cardiogenic shock

Context: Although cerebral perfusion (CP) is preserved across a wide range of mean arterial pressures (MAP) through cerebral-vascular autoregulation, the relationship between MAP and CP in refractory poison-induced cardiogenic shock (PICS) has never been studied. We compared the effects of therapies used in PICS: high-dose insulin (HDI), HDI plus norepinephrine (NE), and vasopressors alone (NE plus epinephrine (Epi)) on cerebral tissue oxygenation (P_tO₂). Methods: Fifteen swine were randomized to either HDI, HDI + NE, or NE + Epi. All animals received a propranolol infusion using an established model of toxicity. At primary toxicity (P₁), defined as a 25% reduction in heart rate (HR) multiplied by MAP, the HDI and HDI + NE groups received HDI and the NE + Epi group received NE. Once a sustained MAP < 55 mmHg was reached (P₂), the HDI group received saline (NS), the HDI + NE group received NE and the NE + Epi group received Epi until death or censoring. P_tO₂ and hemodynamic parameters including MAP, cardiac output (CO) and central venous pressure (CVP) were measured every 10 minutes. Glucose and potassium were measured at predetermined intervals. Results: Animals treated with HDI + NE maintained P_tO₂ over time more than the HDI-alone group. Due to rapid hemodynamic collapse, we were unable to analyze P_tO₂ data in the vasopressor only animals. Mean survival time was 1.9, 2.9 and 0.1 hours for the HDI, HDI + NE and NE + Epi groups, respectively. Survival time from P₂ (sustained MAP <55 mmHg) to death or censoring was not different between HDI and HDI + NE groups. Conclusions: HDI + NE treatment was superior to HDI-alone at preserving P_tO₂ when MAP < 55 mmHg. We were unable to compare the P_tO₂ between the NE + Epi to the HDI or HDI + NE due to rapid decline in CO and death. If MAP is sustained at < 55 mmHg after maximizing HDI, adjunctive treatment with NE should be considered to preserve P_tO₂.

The Use of High-dose Insulin Infusion and Lipid Emulsion Therapy in Concurrent Beta-blocker and Calcium Channel Blocker Overdose

Patients admitted with the presumed coingestion of beta-blockers (BBs) and calcium channel blockers (CCBs) should be initially managed in accordance with standardized resuscitation protocols (the airway, breathing, and circulation (ABC) approach). Additionally, more specific interventions should be promptly attempted. Intravenous glucagon and calcium salts have long been used in the treatment of BB and CCB toxicities. We present a case of a severe, concurrent BB and CCB toxicity resulting in cardiovascular collapse refractory to vasopressors. The administration of high-dose insulin (HDI) and lipid emulsion therapy (LET) resulted in a significant improvement in hemodynamics with an overall favorable outcome in the patient.

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.

β-Blocker and Calcium Channel Blocker Poisoning: High-Dose Insulin/Glucose Therapy

Overdoses of β-blockers and calcium channel blockers can produce significant morbidity and mortality, and conventional therapies often do not work as treatments for these poisonings. High-dose insulin/glucose therapy has been successful in reversing the cardiotoxic effects of these drugs in cases where the standard therapies have failed, and it appears to be relatively safe. Many successes have been well documented, but the clinical experience consists of case reports, the mechanisms of action are not completely understood, and guidelines for use of the therapy are empirically derived and not standardized. Regardless of these limitations, high-dose insulin/glucose therapy can be effective, it is often recommended by clinical toxicologists and poison control centers, and critical care nurses should be familiar with when and how the therapy is used.

The Use of Glucagon and other Antidotes in a Case of Beta-Blocker and Calcium Channel Blocker Overdose

We report a case of metoprolol and nifedipine overdose complicated by hypotension which responded to intravenous boluses of calcium chloride and glucagon. The blood pressure was subsequently stabilised by continuous glucagon infusion with the aid of an insulin-dextrose drip. The discussion is focused on the role of antidotes and catecholamine inotropes in the management of beta-blocker and calcium channel blocker poisoning.

Therapeutic role of hyperinsulinemia/euglycemia in aluminum phosphide poisoning

BACKGROUND

Different protocols have been suggested to treat aluminum phosphide (ALP) poisoning. We aimed to evaluate the possible therapeutic effect of hyperinsulinemia/euglycemia (HIE) in treatment of ALP poisoning.

METHODS

In a prospective interventional study, a total of 88 ALP-poisoned patients were included and assigned into HIE group undergoing glucose/insulin/potassium (GIK) protocol and a control group that was managed by routine conventional treatments. The 2 groups were then compared regarding the signs and symptoms of toxicity and their progression, development of complications, and final outcome to detect the possible effect of GIK protocol on the patients' course of toxicity and outcome.

RESULTS

The 2 groups were similar in terms of demographic characteristics and on-arrival vital signs and lab tests. Using GIK protocol resulted in significantly longer hospital stays (24 vs 60 hours; P < 0.001) and better outcomes (72.7% vs 50% mortality; P = 0.03). Regression analysis showed that GIK duration was an independent variable that could prognosticate mortality (odds ratio [95% confidence interval] = 1.045 [1.004,1.087]). The risk of mortality decreased by 4.5% each hour after initiation of GIK.

CONCLUSION

GIK protocol improves the outcome of ALP poisoning and increases the length of hospital stay.

Multi-drug intoxication fatality involving atorvastatin: A case report

Mixed antihypertensive drug intoxication poses a significant risk for patient mortality. In tandem to antihypertensives, hypolipidemic medicines (especially statins) are often prescribed. Among their well-known adverse effects belongs rhabdomyolysis. We report a case of fatal multi-drug overdose in a 65-year-old female alcoholic. The patient was unconscious at admission. Empty blister packs indicated the abuse of 250 tablets of urapidil, 42 tablets of verapamil/trandolapril, 50 tablets of moxonidin, 80 tablets of atorvastatin and 80 tablets of diacerein. Standard measures (gastric lavage, activated charcoal, mechanical ventilation, massive doses of vasopressors, volume expansion, diuretics and alkalinization) failed to provide sufficient drug elimination and hemodynamic support and the sufferer deceased on the fourth day. Dramatic elevations of serum myoglobin (34,020 μg/L) and creatine kinase (219 μkat/L) were accompanied by rise in cardiac troponin I and creatinine. Gas chromatography revealed ethanol 1.17 g/kg (blood) and 2.81 g/kg (urine). Thin layer chromatography and gas chromatography of gastric content and urine verified verapamil, moxonidin and urapidil fragment (diacerein method was unavailable). Atorvastatin and trandolapril concentrations (LC-MS(n)) equaled 277.7 μg/L and 57.5 μg/L, resp. (serum) and 8.15 μg/L and 602.3 μg/L, resp. (urine). Histology confirmed precipitates of myoglobin with acute necrosis of proximal renal tubules in association with striated muscle rhabdomyolysis and myocardial dystrophy. Cardiogenic-distributive shock in conjunction with acute renal failure due to the combined self-poisoning with vasoactive agents and atorvastatin were determined to be this decedent's immediate cause of death. The manner of death was assigned to be suicidal.

A multifaceted approach to calcium channel blocker overdose: a case report and literature review

Calcium channel blocker toxicity can be devastating. Initial therapy with fluid, calcium, and adrenoreceptor agonists should be prompt and novel therapies can be added if no response. Determining cardiogenic shock versus vasoplegia with echocardiogram or other hemodynamic monitoring may guide treatment options.

Extracorporeal life support and plasmapheresis in a case of severe polyintoxication

BACKGROUND

Resuscitation without return to spontaneous circulation in patients with suicidal ingestion of cardiotoxic drugs necessitates alternative bridging therapies for drug removal.

OBJECTIVES

To show the effectiveness of emergency extracorporeal membrane oxygenation (ECMO) and plasmaspheresis in severe polyintoxication.

CASE REPORT

A 21-year-old woman developed asystole after suicidal polyintoxication with 1.75 g carvedilol, 300 mg amlodipine, 6 g amitriptyline, 500 mg torsemide, 1.5 g ketoprofen, 28 g nicotinic acid, and 16 g gabapentin. After 3 h of cardiopulmonary resuscitation without return to spontaneous circulation, ECMO was used as a bridging therapy and a temporary pacemaker was inserted. Plasma peak levels were measured for amlodipine (29.3 μg/L), amitriptyline (1456 μg/L), carvedilol (585 μg/L), and gabapentin (126.8 mg/L). To facilitate drug removal, therapeutic plasma exchange was performed. The patient could be weaned from ECMO at day 4 and extubated on day 8 after admission without neurologic sequelae.

CONCLUSION

ECMO and plasma exchange should be considered as a therapeutic option in selected patients under resuscitation without return to spontaneous circulation after severe intoxication.

Toxicologic emergencies in the intensive care unit: management using reversal agents and antidotes

PURPOSE

To review the most common drugs implicated in overdoses admitted to the intensive care unit focusing on antidotes and reversal agents used in their management.

SUMMARY

Poisonings and overdoses due to pharmaceutical agents result in more than 100 000 critical care unit admissions each year. Ingestion of toxic alcohols, calcium channel blockers, beta-adrenergic antagonists, benzodiazepines, opioids, acetaminophen, tricyclic antidepressants, and salicylates are associated with a high rate of morbidity and mortality. Reviewing the mechanism of toxicity due to specific agents along with the mechanism of action, dosing, and adverse effects of appropriate antidotes is important for the successful management of these patients within the critical care unit.

CONCLUSION

Understanding the most prevalent overdoses and their management using reversal agents and antidotes is essential to the overall treatment of these critically ill patients.

High dose insulin therapy, an evidence based approach to beta blocker/calcium channel blocker toxicity

Poison-induced cardiogenic shock (PICS) as a result of beta-blocker (β-blocker) or calcium channel blocker (CCB) overdose is a common and potentially life-threatening condition. Conventional therapies, including fluid resuscitation, atropine, cardiac pacing, calcium, glucagon, and vasopressors often fail to improve hemodynamic status. High-dose insulin (HDI) is an emerging therapeutic modality for PICS. In this article, we discuss the existing literature and highlight the therapeutic success and potential of HDI. Based on the current literature, which is limited primarily to case series and animal models, the authors conclude that HDI can be effective in restoring hemodynamic stability, and recommend considering its use in patients with PICS that is not responsive to traditional therapies. Future studies should be undertaken to determine the optimal dose and duration of therapy for HDI in PICS.

Severe diltiazem poisoning treated with hyperinsulinaemia-euglycaemia and lipid emulsion

Introduction. Calcium channel blockers (CCBs) drugs are widely used in the treatment of cardiovascular diseases. CCB poisoning is associated with significant cardiovascular toxicity and is potentially fatal. Currently, there is no specific antidote and the treatment of CCB poisoning is supportive; however, this supportive therapy is often insufficient. We present a clinical case of severe diltiazem poisoning and the therapeutic approaches that were used. Case Report. A 55-year-old male was admitted to the intensive care unit (ICU) after voluntary multiple drug intake, including extended release diltiazem (7200 mg). The patient developed symptoms of refractory shock to conventional therapy and required mechanical ventilation, a temporary pacemaker, and renal replacement therapy. Approximately 17 hours after drug intake, hyperinsulinaemia-euglycaemia with lipid emulsion therapy was initiated, followed by progressive haemodynamic recovery within approximately 30 minutes. The toxicological serum analysis 12 h after drug ingestion revealed a diltiazem serum level of 4778 ng/mL (therapeutic level: 40–200 ng/mL). Conclusions. This case report supports the therapeutic efficacy of hyperinsulinaemia-euglycaemia and lipid emulsion in the treatment of severe diltiazem poisoning.

Cardioprotective effect of glucose-insulin on acute propafenone toxicity in rat

OBJECTIVE

We recently observed a case of propafenone self-poisoning in which the patient was initially unresponsive to conventional therapies such as sodium bicarbonate, dopamine, and norepinephrine but recovered with intravenous glucose-insulin infusion. We raised the hypothesis that insulin may have a cardioprotective effect in acute propafenone toxicity.

METHODS

We evaluated the effect of glucose-insulin infusion on mortality and electrocardiographic abnormalities during acute propafenone toxicity in rats. After measurements of basal mean arterial pressure, heart rate, PR interval, and QRS duration, rats received intravenous propafenone (36 mg/kg per hour) for 12 minutes. Two minutes after the induction of toxicity, the rats (n=10 per group) received either normal saline solution (NSS) or insulin with glucose. Rats in the insulin-treated (Insulin group) and the NSS-treated (NSS group) groups received an intravenous infusion of 36 mg/kg per hour of propafenone until death occurred. Rats receiving only NSS intravenously without propafenone toxicity served as control (Control group, n=10).

RESULTS

Insulin treatment improved survival and delayed the hemodynamic and electrocardiographic consequences of propafenone toxicity. Survival was significantly greater in the insulin group than that in the NSS group (P<.001). Insulin prevented the decline in mean arterial pressure and heart rate (P<.05). Insulin also prevented the increase of the PR interval and the QRS duration (P<.05).

CONCLUSION

Glucose-insulin infusion delayed the abnormalities in cardiac conduction and improved rat survival after acute propafenone toxicity. These results suggest a cardioprotective effect of glucose-insulin in acute propafenone toxicity.

Antidotes for toxicological emergencies: a practical review

PURPOSE

Appropriate therapies for commonly encountered poisonings, medication overdoses, and other toxicological emergencies are reviewed, with discussion of pharmacists' role in ensuring their ready availability and proper use.

SUMMARY

Poisoning is the second leading cause of injury-related morbidity and mortality in the United States, with more than 2.4 million toxic exposures reported each year. Recently published national consensus guidelines recommend that hospitals providing emergency care routinely stock 24 antidotes for a wide range of toxicities, including toxic-alcohol poisoning, exposure to cyanide and other industrial agents, and intentional or unintentional overdoses of prescription medications (e.g., calcium-channel blockers, β-blockers, digoxin, isoniazid). Pharmacists can help reduce morbidity and mortality due to poisonings and overdoses by (1) recognizing the signs and symptoms of various types of toxic exposure, (2) guiding emergency room staff on the appropriate use of antidotes and supportive therapies, (3) helping to ensure appropriate monitoring of patients for antidote response and adverse effects, and (4) managing the procurement and stocking of antidotes to ensure their timely availability.

CONCLUSION

Pharmacists can play a key role in reducing poisoning and overdose injuries and deaths by assisting in the early recognition of toxic exposures and guiding emergency personnel on the proper storage, selection, and use of antidotal therapies.

Levosimendan Does Not Improve Cardiac Output or Blood Pressure in a Rodent Model of Propranolol Toxicity When Administered Using Various Dosing Regimens

Background: Levosimendan (CAS: 141505-33-1) is a myocardial calcium sensitizer that improves myocardial contractility in various forms of heart failure. It produces a moderate improvement in cardiac output (CO) without an improvement in blood pressure (BP) in verapamil and metoprolol poisoned rodents. Aim: To assess the effect of various levosimendan dosing regimens on hemodynamics in a rodent model of propranolol poisoning. Method: Male Wistar rats (350-450 g) were anesthetized, ventilated, and instrumented to record BP, heart rate (HR), and CO. Propranolol was infused continually. When BP dropped to 50% of baseline rats received 1 of 7 treatments: (1) 0.9% saline (control), (2) levosimendan 36 μg/kg loading dose then 0.6 μg/kg per min, (3) levosimendan 0.6 μg/kg per min, (4) epinephrine 0.5 μg/kg per min, (5) levosimendan 70 μg/kg loading dose then 1.2 μg/kg per min, (6) levosimendan 1.2 μg/kg per min, and (7) levosimendan 70 μg/kg loading dose alone. Hemodynamics were recorded every 10 minutes for 70 minutes. Cardiac output, mean arterial pressure, and HR for each group were compared with control. Results: All groups had comparable baseline and maximal toxicity hemodynamics prior to initiation of treatment. Levosimendan did not improve CO or BP with any dosing regimen. Blood pressure tended to be lower than control for all doses of levosimendan. Epinephrine significantly improved BP but not CO compared to all other treatment groups. Survival did not differ between groups. Conclusions: Unlike in verapamil and metoprolol poisoning models, levosimendan did not improve CO or survival in propranolol poisoning. Epinephrine improved BP, but not CO, suggesting that its actions were due to peripheral vasoconstriction.

Levosimendan infusion improves cardiac output but not blood pressure in a rodent model of severe metoprolol toxicity

Levosimendan (Levo) is an inodilator improving cardiac output (CO) and reducing afterload in heart failure. Previously, we reported that Levo improved CO but not blood pressure (BP) in a rodent model of verapamil poisoning. We theorised that Levo-induced vasodilation should not influence BP to a similar degree in metoprolol poisoning. Aim: To assess the effect of Levo on haemodynamics in a rodent model of metoprolol poisoning. Method: Anaesthetized male Wistar rats were infused metoprolol continuously. When the BP dropped to 50% of baseline (time 0) rats received 1 of the 4 treatments: (a) control (0.9% saline bolus + infusion); (b) Levo-l (Levo 36 μm/kg loading dose followed by 0.6 μm/kg/min); (c) Levo-I (Levo infusion only at 0.6 μm/kg/min); and (d) Epi (epinephrine 0.5 μm/kg/min). All groups received comparable fluid volumes. Haemodynamics were recorded every 10 min for 70 min. CO, mean arterial pressure (MAP) and heart rate (HR) of each group were compared to the control. Results: All groups had comparable baseline and time 0 HR, MAP and CO. Levo-L and Levo-I rats showed significantly greater CO at t = 10 min ( p > 0.02 and p > 0.04, respectively). CO was higher at all other time points for both Levo groups. This was not statistically significant. Levo did not improve MAP compared to control. Adrenaline increased MAP but not CO compared to control and Levo groups. Conclusion: Levo did not improve MAP but moderately improved CO compared to control in this model of metoprolol poisoning. The response was similar to that reported previously in verapamil-poisoned rats. The improvement in MAP seen with epinephrine was most likely vasoconstriction mediated.

Addition of phenylephrine to high-dose insulin in dihydropyridine overdose does not improve outcome

INTRODUCTION

Vasopressors are commonly used for calcium channel blocker (CCB)-induced cardiogenic shock after calcium and high-dose insulin (HDI). Vasopressor therapy is frequently used in combination with HDI to increase blood pressure and improve outcome. However, no studies have compared the efficacy of HDI to the combination of a vasopressor and HDI in dihydropyridine overdose. We conducted a study to compare the efficacy of HDI to phenylephrine (PE) plus HDI in a porcine model of dihydropyridine toxicity.

METHODS

Cardiogenic shock was induced by administering a nifedipine (NP) infusion of 0.0125 mcg/kg/min until a point of toxicity, defined as a 25% decrease in the baseline product of mean arterial pressure (MAP) × cardiac output (CO). Each arm was resuscitated with 20 mL/kg of saline (NS). The nifedipine infusion continued throughout a 4-h resuscitation protocol. The HDI group was titrated up to 10 units/kg/h of insulin and the HDI/PE group was titrated up to a dose of HDI 10 units/kg/h plus PE 3.6 mcg/kg/min.

RESULTS

No baseline differences were found among groups including time to toxicity. Survival was not different between the HDI and HDI/PE arms. When comparing the HDI to the HDI/PE arm no differences were found for cardiac index (CI) (p = 0.06), systemic vascular resistance (p = 0.34), heart rate (HR) (p = 0.95), mean arterial pressure (p = 0.99), pulmonary vascular resistance (PVR) (p = 0.07), or base excess (p = 0.36).

CONCLUSION

In this model of nifedipine-induced cardiogenic shock, the addition of PE to HDI therapy did not improve mortality, cardiac output, blood pressure, systemic vascular resistance (SVR), or base excess.

[Successful treatment of polymedicamentous poisoning with metoprolol, diltiazem and cilazapril]

INTRODUCTION

Poisoning caused by drugs with cardiodepressive effects is an urgent condition in medicine which is associated with high mortality rate regardless of modern therapeutic methods. Accidental or intentional poisoning whit these drugs produces heart activity depression and cardiovascular collapse as consequences. Current therapy for severe poisoning caused by beta-blockers and calcium channel blockers includes both unspecific and specific antidote therapy whit glucagon, as well as application of adrenergic drugs, calcium, phosphodiesterase inhibitors and hyperinsulinemia/euglycemia therapy. However, even whit the application of these drugs, prompt measures of unspecific detoxication therapy and cardiopulmonary reanimation are crucial for survival of patients with severe poisoning.

CASE REPORT

A 28-year-old female patient was hospitalized for cardiogenic shock and altered state of conscioussnes (Glasgow coma score = 4), caused by acute poisoning with 2 g of metoprolol (Presolol), 1.8 g of diltiazem (Cortiazem) and 50 mg of cilazapril (Zobox). Prolonged cardiopulmonary resuscitation was applied during the first 16 hours of hospitalization, including administration of crystaline solutions (8 L), 17 mg of adrenaline, 4 mg of atropine, 4 mg of glucagone and 1.6 g of dopamine, with electro-stimulation by temporary pacemaker and mechanical ventilation. In a defined time period, normalized state of consciousness was registered, mechanical ventilation was stopped and normal heart activity and hemodynamic stability were accomplished. During hospitalization the patient was treated for mild pneumonia and after ten days, completely recovered, was released and sent to home treatment.

CONCLUSION

Prompt measures of cardiopulmonary resuscitation and multidisciplinary treatment in intensive care units significantly increase the chances of complete recovery of a patient with severe poisoning caused by drugs with cardiodepressive efects.

Early use of high-dose insulin euglycaemic therapy for verapamil toxicity

A 49-year-old man presented with verapamil toxicity complicated by hypotension and a junctional rhythm, in the context of deliberate self-poisoning with multiple drugs. The patient's hypotension normalised following the early use of high-dose insulin euglycaemic therapy (HIET), without the need for additional vasopressors; it recurred when HIET was prematurely stopped, and again stabilised when HIET was recommenced. Consideration should be given to the early use of HIET in treating severe calcium channel blocker toxicity, rather than as a last resort after other therapies have failed.

The use of high-dose insulin-glucose euglycemia in beta-blocker overdose: a case report

The management of life-threatening beta-blocker toxicity and its associated low cardiac output state is clinically challenging. Previous case reports and case series describe the use of hyperinsulinemia/euglycemia therapy in mono-ingestions of calcium channel blockers and mixed ingestions, including calcium channel and beta-blockers. In this case report we describe the use of high-dose insulin (10 IU/kg per hour) in a case of massive metoprolol ingestion (5g) in which hypotension was unresponsive to conventional therapies. Although the metoprolol concentrations measured in plasma were approximately 100-200 times therapeutic concentrations, the pharmacokinetics appeared to be similar to therapeutic metoprolol dosing.

Toxicology in the critical care unit

Toxicologic conditions are encountered in critically ill patients due to intentional or unintentional misuse of or exposure to therapeutic or illicit drugs. Additionally, toxicities related to medical interventions may develop in hospitalized patients. This review focuses on recent developments in the field of critical care toxicology. Early interventions to decrease absorption or enhance elimination of toxins have limited value. Specific interventions to manage toxicities due to analgesics, sedative-hypnotics, antidepressants, antipsychotics, cardiovascular agents, alcohols, carbon monoxide, and cholinergic agents are reviewed. Hospital-acquired toxicities due to methemoglobinemia, propylene glycol, and propofol should be recognized and treated. The clinician is continually required to incorporate clinical judgment along with available scientific data and clinical evidence to determine the best therapy for toxicologic conditions.

Third-degree AV block from extended-release diltiazem ingestion in a nine-month-old

Calcium channel blocker (CCB) overdose is associated with dysrhythmias and atrioventricular (AV) block, however, experience with infant CCB overdose is limited. A 9-month-old girl was found playing with tablets of extended-release diltiazem 120 mg. The patient had two episodes of emesis, which contained pill fragments, and was brought to the Emergency Department (ED) 4.5 h after being found. Vital signs were: rectal temperature 37.1 degrees C, pulse 87 beats/min, respiratory rate 30-40 breaths/min, blood pressure 72/48 mm Hg, and oxygen saturation (SpO(2)) 99% on room air. Otherwise, the patient was well-appearing, with normal skin color and examination. The electrocardiogram revealed third-degree atrioventricular block with a ventricular rate of 90 beats/min, QRS 68 ms, and QTc 411 ms. Atropine 0.1 mg i.v. was given, which increased the heart rate to 100-110 beats/min. Calcium gluconate 500 mg was also given intravenously. Laboratory evaluation revealed bicarbonate 17 mEq/L, anion gap 16, and glucose 129 mg/dL. On hospital day 1, the patient was noted to have a junctional rhythm with a rate of 90-100, and systolic blood pressure of 80-90 mm Hg. No additional medications were given. Early on day 2, the patient converted spontaneously to a normal sinus rhythm and was discharged approximately 42 h after presentation to the ED. In addition to bradycardia and hypotension, this 9-month-old patient manifested third-degree AV block after ingesting extended-release diltiazem.

HEXOSAMINE BIOSYNTHESIS AND PROTEIN O-GLYCOSYLATION

An early and rapid response to severe injury or trauma is the development of hyperglycemia, which has long been thought to be an essential survival response by providing fuel for vital organ systems and facilitating mobilization of interstitial fluid reserves by increasing osmolarity. However, glucose can also be metabolized via the hexosamine biosynthesis pathway (HBP), leading to the synthesis of uridine diphosphate N-acetyl-glucosamine(UDP-GlcNAc). UDP-GlcNAc is a substrate for the addition, via an O-linkage, of a single N-acetylglucosamine to serine or threonine residues of nuclear and cytoplasmic proteins (O-glycosylation, O-GlcNAc). There is increasing appreciation that protein O-glycosylation is a highly dynamic posttranslational modification that plays a key role in signal transduction pathways. Sustained increases in O-GlocNAc have been implicated in the development of diabetes and diabetic complications; however, recent studies have demonstrated that stress leads to a transient increase in O-GlcNAc levels that is associated with increased tolerance to stress. Indeed, activation of pathways leading to O-GlcNAc formation improves cell survival after I/R injury, whereas inhibition of O-GlcNAc formation decreases cell survival. In addition, in rodent models of trauma-hemorrhage, increasing O-GlcNAc levels during resuscitation improves cardiac function and organ perfusion and attenuates the inflammatory response. At the cellular level, increasing O-GlcNAc levels attenuates nuclear factor-kappaB activation. It is noteworthy that other metabolic-based treatments for severe injury such as glucose-insulin-potassium and glutamine also lead to increased HBP flux and O-GlcNAc levels. The goal of this review is to summarize our current understanding of the role of the HBP and O-GlcNAc on the regulation of cell function and survival and to present evidence to support the notion that activation of these pathways represents a novel treatment strategy for severe injury and trauma.

Assessment of hyperglycemia after calcium channel blocker overdoses involving diltiazem or verapamil

BACKGROUND

Overdoses of calcium channel blocker agents result in hyperglycemia, primarily due to the blockade of pancreatic L-type calcium channels and insulin resistance on the cellular level. The clinical significance of the hyperglycemia in this setting has not previously been described.

METHODS

This study is a retrospective review of all adult (age, >or=15 yrs) patients with a discharge diagnosis of acute verapamil or diltiazem overdose at five university-affiliated teaching hospitals. The severity of overdose was assessed by determining whether a patient met the composite end points of in-hospital mortality, the necessity for a temporary pacemaker, or the need for vasopressors. We compared the initial and peak serum glucose concentrations with hemodynamic variables between patients who did and did not meet the composite end points.

RESULTS

A total of 40 patients met inclusion criteria, with verapamil and diltiazem accounting for 27 of 40 (67.5%) and 13 of 40 (32.5%) of the ingestions, respectively. For those patients who did and did not meet the composite end points, the median initial serum glucose concentrations were 188 (interquartile range, 143.5-270.5) mg/dL and 129 (98.5-156.5) mg/dL, respectively (p = .0058). The median peak serum glucose concentrations for these two groups were 364 (267.5-408.5) mg/dL and 145 (107.5-160.5) mg/dL, respectively (p = .0001). The median increase in blood glucose was 71.2% for those who met composite end points vs. 0% for those who did not meet composite end points (p = .0067). Neither the change in the median heart rate nor the change in systolic blood pressure was significantly different in any group.

CONCLUSION

Serum glucose concentrations correlate directly with the severity of the calcium channel blocker intoxication. The percentage increase of the peak glucose concentration is a better predictor of severity of illness than hemodynamic derangements. If validated prospectively, serum glucose concentration alone might be an indicator to begin hyperinsulinemia-euglycemia therapy.

‘Silent’ Prinzmetal’s ST Elevation Related to Atenolol Overdose

Prinzmetal's angina is a condition characterized by chest pain, transient ST elevation, and negative biochemical markers of myocardial cell necrosis. We describe a case of chemically-induced "silent" ST segment elevation related to Atenolol overdose in a patient without coronary artery stenosis. We conclude that the cause for the transient myocardial ischemia is coronary vasospasm, precipitated by beta-blocker overdose.

Relative safety of hyperinsulinaemia/euglycaemia therapy in the management of calcium channel blocker overdose: a prospective observational study

OBJECTIVE

To examine the clinical safety of hyperinsulinaemia/euglycaemia therapy (HIET) in calcium channel blocker (CCB) poisoning.

DESIGN

A prospective observational study examining biochemical and clinical outcomes of a HIET protocol administered under local poisons centre guidance.

SETTING

Critical care settings.

PATIENTS

Seven patients with significant CCB toxicity [systolic blood pressure (BP) <90 mmHg] treated with HIET.

INTERVENTIONS

HIET was commenced after correction of any pre-existing hypoglycaemia ([blood glucose]<65 mg/dl) or hypokalaemia ([K+]<3.5mmol/l). A quantity of 50 ml of 50% intravenous dextrose was followed by a loading dose (1 unit/kg) of intravenous short-acting insulin and an insulin maintenance infusion (0.5-2.0 units/kg/h). Euglycaemia was maintained using 5-10% dextrose infusions. Potassium was maintained within low normal range (3.8-4.0 mmol/l).

MEASUREMENTS AND RESULTS

Six patients survived. All patients received fluids, calcium, and conventional inotropes. Three patients (who all ingested diltiazem) received an insulin-loading dose; all experienced a significant sustained rise in systolic BP (>10 mmHg) during the first hour of HIET. Systolic BP did not increase significantly in four patients who did not receive insulin loading. Single episodes of non-clinically significant biochemical hypoglycaemia and hypokalaemia were recorded in one and two patients respectively. Hypoglycaemia was not recorded in any patient administered HIET during the 24[Symbol: see text]h following CCB ingestion.

CONCLUSIONS

HIET used to treat CCB-induced cardiovascular toxicity is a safe intervention when administered in a critical care setting. Maximal HIET efficacy may be obtained when HIET is administered in conjunction with conventional therapy relatively early in the course of severe CCB poisoning when insulin resistance is high.

Extracorporeal life support in a case of acute carbamazepine poisoning with life-threatening refractory myocardial failure

OBJECTIVE

To report the efficacy of extracorporeal life support (ECLS) in acute carbamazepine poisoning with sustained refractory myocardial failure and a high degree of conductance disturbances.

DESIGN AND SETTING

Case report from the toxicological and medical intensive care unit in a university hospital.

PATIENT

A 26-year-old man with severe myocardial failure unresponsive to 1.7 microg kg(-1) min(-1) epinephrine and 1.9 microg kg(-1) min(-1) norepinephrine (SvO2, 17.8% and cardiac index, 0.8 l min(-1) m(-2)) following a suicidal ingestion of 32 g slow-release carbamazepine.

INTERVENTIONS

ECLS (Jostra-Maquet centrifugal pump (Rotaflow) connected to a hollow-fiber membrane oxygenator).

MEASUREMENTS AND RESULTS

ECLS device allowed inotropic drug weaning while maintaining end-organ function and supported the patient until myocardial recovery. The plasma carbamazepine level was 224 micromol/l on admission and peaked at 338 micromol/l 101 h after admission with a prolonged gastrointestinal absorption phase despite multiple doses of activated charcoal. The patient survived and was successfully explanted on day 6. An extensive and regressive thrombosis of the inferior vena cava was noted. Cardiac function totally recovered and at 2-year follow-up. There were no significant sequelae.

CONCLUSIONS

We report a case of life-threatening myocardial failure with conductance disturbances secondary to an acute carbamazepine poisoning, demonstrating the efficacy of ECLS to assist recovery.

Cardio protective effect of glucose–insulin infusion on acute digoxin toxicity in rat

We recently observed a case of digoxin and insulin self-poisoning without cardiac repercussion. We raised the hypothesis that insulin may have a cardio-protective effect in case of digoxin toxicity. We have therefore evaluated the effect of glucose-insulin infusion on mortality and ECG abnormalities during acute digoxin toxicity in rats. Before and after a hyperinsulinemia-euglycemia clamp, rats in glucose-insulin-digoxin (GID) group (n=10) received an intravenous infusion of 12ml/h or 2,5ml/h digoxin (0.25mg/ml) respectively until death occured. Animals receiving digoxin or saline solution intravenously served as control (n=10). ECG recording was performed in all animals over the entire period. Serum insulin and digoxin concentrations were measured by ELISA method after digoxin administration. When digoxin was administered after the clamp, all animals in GID group were alive, whereas 80% of animals in the digoxin group were dead (p<0.001) after 30min. The administration of Digoxin provoked rapid death of rats in the digoxin group in 15+/-12min whereas in GID group the survival period was significantly increased to 38+/-3min (p<0.001). Twenty minutes after digoxin administration, P waves disappeared for 78% of animals in digoxin group while they were present in all rats of GID group (p<0.001). Animal death occurred after a digoxin infusion volume of 7.7+/-0.6ml and 3.0+/-2.4ml in GID and digoxin group respectively (p<0.001). Five minutes after digoxin administration, potassium plasmatic level increased significantly in digoxin group as compared to GID group: 7.1+/-2mmol/l versus 4.4+/-0.4mmol/l (p<0.001). When digoxin was infused before the clamp, 40% of animals in GID group were alive after 180min and the other 60% died after 137+/-40min whereas death of rats in the digoxin group occurred within 80+/-10min (p<0.001). The death of animals was preceded by the P waves disappearing. Thirty minutes after digoxin administration, the potassium plasmatic level increased significantly in the digoxin group as compared to the GID group: 6.9+/-0.5mmol/l versus 4.9+/-0.3mmol/l (p<0.001). At the time of death, both volume of digoxin infusion and serum digoxin concentration were increased in GID group as compared to digoxin group: 5.7+/-1.6ml versus 3.3+/-0.4ml (p<0.001) and 10.7+/-8.3mg/l versus 8.5+/-4.6mg/l.

CONCLUSION

Glucose-insulin infusion delayed the abnormalities in cardiac conduction and improved rat survival after acute digoxin toxicity. These results suggest a cardioprotective effect of insulin in case of acute digoxin toxicity.

Bench-to-bedside review: hyperinsulinaemia/euglycaemia therapy in the management of overdose of calcium-channel blockers

Hyperinsulinaemia/euglycaemia therapy (HIET) consists of the infusion of high-dose regular insulin (usually 0.5 to 1 IU/kg per hour) combined with glucose to maintain euglycaemia. HIET has been proposed as an adjunctive approach in the management of overdose of calcium-channel blockers (CCBs). Indeed, experimental data and clinical experience, although limited, suggest that it could be superior to conventional pharmacological treatments including calcium salts, adrenaline (epinephrine) or glucagon. This paper reviews the patho-physiological principles underlying HIET. Insulin administration seems to allow the switch of the cell metabolism from fatty acids to carbohydrates that is required in stress conditions, especially in the myocardium and vascular smooth muscle, resulting in an improvement in cardiac contractility and restored peripheral resistances. Studies in experimental verapamil poisoning in dogs have shown that HIET significantly improves metabolism, haemodynamics and survival in comparison with conventional therapies. Clinical experience currently consists only of a few isolated cases or short series in which the administration of HIET substantially improved cardiovascular conditions in life-threatening CCB poisonings, allowing the progressive discontinuation of vasoactive agents. While we await further well-designed clinical trials, some rational recommendations are made about the use of HIET in severe CBB overdose. Although the mechanism of action is less well understood in this condition, some experimental data suggesting a potential benefit of HIET in β-adrenergic blocker toxicity are discussed; clinical data are currently lacking.

Diagnosis and management of the poisoned child

Pediatric toxic ingestions are treated commonly by pediatricians and emergency physicians. Significant injury after these ingestions is infrequent, but identifying the dangerous ingestion is sometimes a difficult task. By performing a detailed history, focused physical examination, and directed laboratory evaluation, an estimation of risk can be developed. This article introduced the term "toxic triage" to describe this process. The toxic triage estimation allows the clinician to make thoughtful decontamination and treatment decisions. Familiarity with the literature supporting or refuting each decontamination method allows educated decisions to be made. Supportive care is an integral part of treatment for all poisonings, from asymptomatic to life-threatening. Most antidotes are used rarely in clinical practice, but familiarity with common antidotes benefits those patients with specific hazardous ingestions. Prevention efforts have the potential to decrease the incidence of pediatric poisonings. The universal poison control center number provided should be distributed and posted in homes, clinics, and emergency departments.

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

Calcium channel blockers (CCB) and beta-blockers (BB) account for approximately 40% of cardiovascular drug exposures reported to the American Association of Poison Centers. However, these drugs represent >65% of deaths from cardiovascular medications. Yet, caring for patients poisoned with these medications can be extremely difficult. Severely poisoned patients may have profound bradycardia and hypotension that is refractory to standard medications used for circulatory support.Calcium plays a pivotal role in cardiovascular function. The flow of calcium across cell membranes is necessary for cardiac automaticity, conduction and contraction, as well as maintenance of vascular tone. Through differing mechanisms, CCB and BB interfere with calcium fluxes across cell membranes. CCB directly block calcium flow through L-type calcium channels found in the heart, vasculature and pancreas, whereas BB decrease calcium flow by modifying the channels via second messenger systems. Interruption of calcium fluxes leads to decreased intracellular calcium producing cardiovascular dysfunction that, in the most severe situations, results in cardiovascular collapse.Although, CCB and BB have different mechanisms of action, their physiological and toxic effects are similar. However, differences exist between these drug classes and between drugs in each class. Diltiazem and especially verapamil tend to produce the most hypotension, bradycardia, conduction disturbances and deaths of the CCB. Nifedipine and other dihydropyridines are generally less lethal and tend to produce sinus tachycardia instead of bradycardia with fewer conduction disturbances.BB have a wider array of properties influencing their toxicity compared with CCB. BB possessing membrane stabilising activity are associated with the largest proportion of fatalities from BB overdose. Sotalol overdoses, in addition to bradycardia and hypotension, can cause torsade de pointes. Although BB and CCB poisoning can present in a similar fashion with hypotension and bradycardia, CCB toxicity is often associated with significant hyperglycaemia and acidosis because of complex metabolic derangements related to these medications. Despite differences, treatment of poisoning is nearly identical for BB and CCB, with some additional considerations given to specific BB. Initial management of critically ill patients consists of supporting airway, breathing and circulation. However, maintenance of adequate circulation in poisoned patients often requires a multitude of simultaneous therapies including intravenous fluids, vasopressors, calcium, glucagon, phosphodiesterase inhibitors, high-dose insulin, a relatively new therapy, and mechanical devices. This article provides a detailed review of the pharmacology, pathophysiology, clinical presentation and treatment strategies for CCB and BB overdoses.