Alleviation of cocaine-induced coronary vasoconstriction by nitroglycerin

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

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

Acute Cardiovascular Toxicity of Cocaine

Cocaine is one of the most commonly abused drugs and represents a major public health concern. Cocaine users frequently present to the emergency department, with chest pain being the most common presenting complaint. The incidence of acute myocardial infarction in patients with cocaine-associated chest pain is often quoted as 6%, but it is highly variable depending on the included population. Risk assessment can be challenging in these patients; serial assessment of electrocardiograms and troponins is often required. This review focuses on the assessment and management of patients presenting with cocaine-associated chest pain and cardiotoxicity. Specific treatments are discussed, including benzodiazepines, nitroglycerin, calcium channel blockers, and phentolamine, and how treatment priorities differ from patients with noncocaine presentations. The use of beta-blockers in this population remains controversial, and the literature around its use is reviewed. The most recent literature and recommendations for the use of percutaneous coronary intervention and fibrinolytics in cocaine-associated myocardial infarction is discussed as well. Cocaine-associated dysrhythmias are suggested to be the cause of sudden cardiac death in some users. The pathophysiology and evidence-based treatments for dysrhythmias are reviewed. This review provides evidence-based recommendations for the assessment and management of patients presenting with cocaine-associated cardiovascular toxicity.

Cocaine induced heart failure: report and literature review

Heart failure is a complex clinical syndrome associated with high mortality and morbidity, creating a major public healthcare problem. It has a variety of etiologies, including substance abuse. Cocaine-induced cardiotoxicity is caused by direct effects of inhibition of sodium channels and indirect effects by inhibiting catecholamine uptake leading to increased sympathetic activity. Management is through the cessation of cocaine use and implantation of guideline-directed medical therapy for heart failure with the exception of beta-blockers as their safe usage is still controversial due to the risk of the unopposed alpha-adrenergic activity. Dexmedetomidine (Precedex) and Benzodiazepines (i.e., midazolam) are options for patients that demonstrate signs and symptoms of acute cocaine intoxication. If the actions of benzodiazepines fail to achieve hemodynamic stability, nitroglycerin may be used (especially in patients with cocaine-associated chest pain and hypertension). Cardiac transplantation is recommended for those who have demonstrated severe cardiovascular disease from cocaine. We present a 43-year-old male with a long-standing history of cocaine use who developed cardiomyopathy and severe acute decompensated heart failure found to have an ejection fraction of <20% admitted to the intensive care unit. He required inotropic support with milrinone and mechanical ventilation. He was later extubated and then discharged with an outpatient evaluation for a cardiac transplant.

Cocaine and Cardiotoxicity: A Literature Review

Long-term cocaine use, as well as acute cocaine use, is associated with adverse cardiovascular consequences, including arrhythmias, angina, myocardial infarction, heart failure, and other conditions. Over the long term, cocaine can result in structural changes to the heart such as increased left-ventricular mass and decreased left-ventricular end-diastolic volume. Patients arriving with cocaine-associated cardiovascular complaints may not be forthcoming about their cocaine or polysubstance abuse or may be unresponsive. The role of beta-blockers, a first-line treatment for many forms of heart disease, is controversial in this population. Cocaine is a powerful sympathomimetic agent, and it was thought that beta-blockade would result in unopposed alpha-adrenergic stimulation and adverse consequences. A number of small, single-center, retrospective and observational studies suggest that beta-blockers may be safe, effective, and beneficial in this population. Further study is needed to clarify the role of beta-blockers in this population. 

Peripheral Administration of Nitroglycerin in Pulseless Ventricular Tachycardia due to Cocaine-Induced Coronary Vasospasm

Cocaine use accounts for 40% of the annual drug use related emergency department visits in the United States. Cocaine use is hence recognized as a major health problem. Cocaine blocks the presynaptic reuptake of norepinephrine and dopamine. The resulting increased adrenergic activity leads to vasoconstriction. Additionally, via various mechanisms, cocaine leads to a prothrombotic state and increases myocardial demand. Cocaine can cause coronary vasospasm and is therefore, associated with acute myocardial injury even in the absence of pre-existing atherosclerotic coronary artery disease. Nitroglycerin has a class 1C indication by the ACCF/AHA guidelines for patients with ST-segment elevation or depression that accompanies ischemic chest discomfort in the setting of cocaine use. It has been shown to reverse cocaine-induced coronary vasospasm and chest pain. In this case report, for the first time, we discuss how intravenous administration of high dose nitroglycerin to a patient in pulseless ventricular tachycardia with angiographically confirmed vasospasm induced by cocaine resulted in return of spontaneous circulation.

Pathophysiology and management of recreational drug-related acute coronary syndrome: ANMCO position statement

Recreational drug use may cause coronary artery disease through several mechanisms. An increasing number of young patients with drug-related acute coronary syndrome have been reported over recent years. The present position statement reports the most recent epidemiological data on acute coronary syndrome in the setting of drug abuse, describes the main pathophysiological mechanisms underlying coronary artery disease and acute events in these patients, and provides practical recommendations on management and an overview of prognosis.

Heightened risk of cardiac events following percutaneous coronary intervention for cocaine-associated myocardial infarction

INTRODUCTION

Several works have suggested heightened risk for cardiac events in cocaine users following percutaneous coronary intervention (PCI). Such studies have generally been performed in small, poorly defined samples and have not utilised optimal control groups. We aimed to define the short-term risk for death or recurrent myocardial infarction (MI) when PCI was performed for myocardial infarction in subjects presenting with urine toxicology positive for cocaine in relation to subjects testing negative for cocaine use.

MATERIAL AND METHODS

Our institutional electronic health record (EHR) was queried for all subjects with urine toxicology performed for cocaine exposure within 5 days before or after having elevated troponin-T assay between 1/1/08 and 12/31/13. Query results were cross-referenced with our institutional cardiology database to identify the sample who had PCI on the same admission as the cocaine test. Subsequent readmission for MI was assessed from the EHR, and deaths were identified from the National Death Index.

RESULTS

PCI had been performed in 380 subjects who tested negative for cocaine and 44 subjects who tested positive. In the cocaine-positive group, incidences of death or MI at 30 days and 1 year were 18% and 23%, respectively. Those who tested positive for cocaine had increased odds (odds ratio (OR) = 2.3, 95% confidence interval (CI): 1.0-5.1, p = 0.04) for death or MI at 30 days post PCI, after adjustment for age, sex, prior MI, and comorbidity index. Although the odds for events 1-year post PCI were not increased (OR = 2.0, 95% CI: 0.9-4.3), the p-value approached significance in this small sample (p = 0.09).

CONCLUSIONS

This retrospective study suggests that PCI performed in cocaine-associated myocardial infarction comes with a high 30-day and one-year risk. Further prospective studies are needed to better define this risk and to lend insight into better management strategies.

ESC Council on hypertension position document on the management of hypertensive emergencies

Hypertensive emergencies are those situations where very high blood pressure (BP) values are associated with acute organ damage, and therefore, require immediate, but careful, BP reduction. The type of acute organ damage is the principal determinant of: (i) the drug of choice, (ii) the target BP, and (iii) the timeframe in which BP should be lowered. Key target organs are the heart, retina, brain, kidneys, and large arteries. Patients who lack acute hypertension-mediated end organ damage do not have a hypertensive emergency and can usually be treated with oral BP-lowering agents and usually discharged after a brief period of observation.

Cocaine-Associated Myocardial Infarction

Myocardial ischaemia and infarction has become a well-recognized sequelae of cocaine use. The possibility of recent cocaine use should be assessed in patients with potential myocardial ischaemia because the treatment of patients with myocardial ischaemia related to cocaine differs from that of patients with myocardial ischaemia unrelated to cocaine. Patients with cocaine-associated myocardial ischaemia should receive initial treatment with benzodiazepines to decrease central adrenergic stimulation. Aspirin should be used to reduce thrombus formation, and nitroglycerin to reverse coronary vasoconstriction. Patients with continued ischaemia can be treated with either low doses of phentolamine, or verapamil. If ischaemia continues after treatment with these agents mechanical reperfusion or thrombolytic therapy should be considered depending upon the clinical circumstances. Patients with myocardial ischaemia secondary to cocaine should not receive treatment with beta adrenergic antagonists as these agents enhance coronary vasoconstriction thereby worsening ischaemia.

The Cardiovascular Effects of Cocaine

Cocaine is the leading cause for drug-abuse-related visits to emergency departments, most of which are due to cardiovascular complaints. Through its diverse pathophysiological mechanisms, cocaine exerts various adverse effects on the cardiovascular system, many times with grave results. Described here are the varied cardiovascular effects of cocaine, areas of controversy, and therapeutic options.

Treatment of cocaine cardiovascular toxicity: a systematic review

INTRODUCTION

Cocaine abuse is a major worldwide health problem. Patients with acute cocaine toxicity presenting to the emergency department may require urgent treatment for tachycardia, dysrhythmia, hypertension, and coronary vasospasm, leading to pathological sequelae such as acute coronary syndrome, stroke, and death.

OBJECTIVE

The objective of this study is to review the current evidence for pharmacological treatment of cardiovascular toxicity resulting from cocaine abuse.

METHODS

MEDLINE, PsycINFO, Database of Abstracts of Reviews of Effects (DARE), OpenGrey, Google Scholar, and the Cochrane Library were searched from inception to November 2015. Articles on pharmacological treatment involving human subjects and cocaine were selected and reviewed. Evidence was graded using Oxford Centre for Evidence-Based Medicine guidelines. Treatment recommendations were compared to current American College of Cardiology/American Heart Association guidelines. Special attention was given to adverse drug events or treatment failure. The search resulted in 2376 articles with 120 eligible involving 2358 human subjects. Benzodiazepines and other GABA-active agents: There were five high-quality (CEBM Level I/II) studies, three retrospective (Level III), and 25 case series/reports (Level IV/V) supporting the use of benzodiazepines and other GABA-active agents in 234 subjects with eight treatment failures. Benzodiazepines may not always effectively mitigate tachycardia, hypertension, and vasospasm from cocaine toxicity. Calcium channel blockers: There were seven Level I/II, one Level III, and seven Level IV/V studies involving 107 subjects and one treatment failure. Calcium channel blockers may decrease hypertension and coronary vasospasm, but not necessarily tachycardia. Nitric oxide-mediated vasodilators: There were six Level I/II, one Level III, and 25 Level IV/V studies conducted in 246 subjects with 11 treatment failures and two adverse drug events. Nitroglycerin may lead to severe hypotension and reflex tachycardia. Alpha-adrenoceptor blocking drugs: There were two Level I studies and three case reports. Alpha-1 blockers may improve hypertension and vasospasm, but not tachycardia, although evidence is limited. Alpha-2-adrenoceptor agonists: There were two high-quality studies and one case report detailing the successful use of dexmedetomidine. Beta-blockers and β/α-blockers: There were nine Level I/II, seven Level III, and 34 Level IV/V studies of β-blockers, with 1744 subjects, seven adverse drug events, and three treatment failures. No adverse events were reported for use of combined β/α-blockers such as labetalol and carvedilol, which were effective in attenuating both hypertension and tachycardia. Antipsychotics: Seven Level I/II studies, three Level III studies, and seven Level IV/V case series and reports involving 168 subjects have been published. Antipsychotics may improve agitation and psychosis, but with inconsistent reduction in tachycardia and hypertension and risk of extrapyramidal adverse effects. Other agents: There was only one high level study of morphine, which reversed cocaine-induced coronary vasoconstriction but increased heart rate. Other agents reviewed included lidocaine, sodium bicarbonate, amiodarone, procainamide, propofol, intravenous lipid emulsion, propofol, and ketamine.

CONCLUSIONS

High-quality evidence for pharmacological treatment of cocaine cardiovascular toxicity is limited but can guide acute management of associated tachycardia, dysrhythmia, hypertension, and coronary vasospasm. Future randomized prospective trials are needed to evaluate new agents and further define optimal treatment of cocaine-toxic patients.

Impact of an abbreviated cardiac enzyme protocol to aid rapid discharge of patients with cocaine-associated chest pain in the clinical decision unit

Introduction

In 2007 there were 64,000 visits to the emergency department (ED) for possible myocardial infarction (MI) related to cocaine use. Prior studies have demonstrated that low- to intermediate-risk patients with cocaine-associated chest pain can be safely discharged after 9–12 hours of observation. The goal of this study was to determine the safety of an 8-hour protocol for ruling out MI in patients who presented with cocaine-associated chest pain.

Methods

We conducted a retrospective review of patients treated with an 8-hour cocaine chest pain protocol between May 1, 2011 and November 30, 2012 who were sent to the clinical decision unit (CDU) for observation. The protocol included serial cardiac biomarker testing with Troponin-T, CK-MB (including delta CK-MB), and total CK at 0, 2, 4, and 8 hours after presentation with cardiac monitoring for the observation period. Patients were followed up for adverse cardiac events or death within 30 days of discharge.

Results

There were 111 admissions to the CDU for cocaine chest pain during the study period. One patient had a delta CK-MB of 1.6 ng/ml, but had negative Troponin-T at all time points. No patient had a positive Troponin-T or CK-MB at 0, 2, 4 or 8 hours, and there were no MIs or deaths within 30 days of discharge. Most patients were discharged home (103) and there were 8 inpatient admissions from the CDU. Of the admitted patients, 2 had additional stress tests that were negative, 1 had additional cardiac biomarkers that were negative, and all 8 patients were discharged home. The estimated risk of missing MI using our protocol is, with 99% confidence, less than 5.1% and with 95% confidence, less than 3.6% (99% CI, 0–5.1%; 95% CI, 0–3.6%).

Conclusion

Application of an abbreviated cardiac enzyme protocol resulted in the safe and rapid discharge of patients presenting to the ED with cocaine-associated chest pain.

Treatment of toxicity from amphetamines, related derivatives, and analogues: a systematic clinical review

BACKGROUND

Overdose of amphetamine, related derivatives, and analogues (ARDA) continues to be a serious worldwide health problem. Patients frequently present to the hospital and require treatment for agitation, psychosis, and hyperadrenegic symptoms leading to pathologic sequelae and mortality.

OBJECTIVE

To review the pharmacologic treatment of agitation, psychosis, and the hyperadrenergic state resulting from ARDA toxicity.

METHODS

MEDLINE, PsycINFO, and the Cochrane Library were searched from inception to September 2014. Articles on pharmacologic treatment of ARDA-induced agitation, psychosis, and hyperadrenergic symptoms were selected. Evidence was graded using Oxford CEBM. Treatment recommendations were compared to current ACCF/AHA guidelines.

RESULTS

The search resulted in 6082 articles with 81 eligible treatment involving 835 human subjects. There were 6 high-quality studies supporting the use of antipsychotics and benzodiazepines for control of agitation and psychosis. There were several case reports detailing the successful use of dexmedetomidine for this indication. There were 9 high-quality studies reporting the overall safety and efficacy of β-blockers for control of hypertension and tachycardia associated with ARDA. There were 3 high-quality studies of calcium channel blockers. There were 2 level I studies of α-blockers and a small number of case reports for nitric oxide-mediated vasodilators.

CONCLUSIONS

High-quality evidence for pharmacologic treatment of overdose from ARDA is limited but can help guide management of acute agitation, psychosis, tachycardia, and hypertension. The use of butyrophenone and later-generation antipsychotics, benzodiazepines, and β-blockers is recommended based on existing evidence. Future randomized prospective trials are needed to evaluate new agents and further define treatment of these patients.

Extracorporeal membrane oxygenation for profound cardiogenic shock due to cocaine toxicity

Cocaine toxicity can result in myocardial infarction from coronary vasospasm. The current treatment algorithm includes intravenous and/or intracoronary vasodilator administration with an expectantly quick resolution of symptoms and signs of ischemia. However, in situations in which myocardial injury persists, the optimal management is uncertain. We present a case in which extracorporeal membrane oxygenation effectively stabilized a patient with ongoing hemodynamic instability who experienced repeated episodes of myocardial injury and ventricular tachyarrhythmias due to cocaine toxicity. <Learning objective: In many urban settings, cocaine-induced angina is not uncommon. The pathogenesis of its manifestation includes coronary artery vasospasm and decreased left ventricular function. Treatment typically involves systemic vasodilators, such as nitrates and calcium channel blockers. However, in patients with substantial hemodynamic instability, these agents might result in a worsening of systemic perfusion. Accordingly, extracorporeal membrane oxygenation should be considered in such cases to promote myocardial recovery.>.

Cocaine-induced vasoconstriction in the human coronary microcirculation: new evidence from myocardial contrast echocardiography

BACKGROUND

Cocaine is a major cause of acute coronary syndrome, especially in young adults; however, the mechanistic underpinning of cocaine-induced acute coronary syndrome remains limited. Previous studies in animals and in patients undergoing cardiac catheterization suggest that cocaine constricts coronary microvessels, yet direct evidence is lacking.

METHODS AND RESULTS

We used myocardial contrast echocardiography to test the hypothesis that cocaine causes vasoconstriction in the human coronary microcirculation. Measurements were performed at baseline and after a low, nonintoxicating dose of intranasal cocaine (2 mg/kg) in 10 healthy cocaine-naïve young men (median age, 32 years). Postdestruction time-intensity myocardial contrast echocardiography kinetic data were fit to the equation y=A(1-e(-βt)) to quantify functional capillary blood volume (A), microvascular flow velocity (β), and myocardial perfusion (A×β). Heart rate, mean arterial pressure, and left ventricular work (2-dimensional echocardiography) were measured before and 45 minutes after cocaine. Cocaine increased mean arterial pressure (by 14±2 mm Hg [mean±SE]), heart rate (by 8±3 bpm), and left ventricular work (by 50±18 mm Hg·mL(-1)·bpm(-1)). Despite the increases in these determinants of myocardial oxygen demand, myocardial perfusion decreased by 30% (103.7±9.8 to 75.9±10.8 arbitrary units [AU]/s; P<0.01) mainly as a result of decreased capillary blood volume (133.9±5.1 to 111.7±7.7 AU; P<0.05) with no significant change in microvascular flow velocity (0.8±0.1 to 0.7±0.1 AU).

CONCLUSIONS

In healthy cocaine-naïve young adults, a low-dose cocaine challenge evokes a sizeable decrease in myocardial perfusion. Moreover, the predominant effect is to decrease myocardial capillary blood volume rather than microvascular flow velocity, suggesting a specific action of cocaine to constrict terminal feed arteries.

Rethinking cocaine-associated chest pain and acute coronary syndromes

Every year more than 500,000 patients present to the emergency department with cocaine-associated complications, most commonly chest pain. Many of these patients undergo extensive work-up and treatment. Much of the evidence regarding cocaine's cardiovascular effects, as well as the current management of cocaine-associated chest pain and acute coronary syndromes, is anecdotally derived and based on studies written more than 2 decades ago that involved only a few patients. Newer studies have brought into question many of the commonly held theories and practices regarding the etiology, diagnosis, and treatment of this common clinical scenario. However, there continues to be a paucity of prospective, randomized trials addressing this topic as it relates to clinical outcomes. We searched PubMed for English-language articles from 1960 to 2011 using the keywords cocaine, chest pain, coronary arteries, myocardial infarction, emergency department, cardiac biomarkers, electrocardiogram, coronary computed tomography, observation unit, β-blockers, benzodiazepines, nitroglycerin, calcium channel blockers, phentolamine, and cardiomyopathy; including various combinations of these terms. We reviewed the abstracts to confirm relevance, and then full articles were extracted. References from extracted articles were also reviewed for relevant articles. In this review, we critically evaluate the limited historical evidence underlying the current teachings on cocaine's cardiovascular effects and management of cocaine-associated chest pain. We aim to update the reader on more recent, albeit small, studies on the emergency department evaluation and clinical and pharmacologic management of cocaine-associated chest pain. Finally, we summarize recent guidelines and review an algorithm based on the current best evidence.

Miscellaneous causes of pediatric chest pain

This article describes some of the miscellaneous etiologies of pediatric chest pain that are important to recognize early and diagnose. Up to 45% of pediatric chest pain cases may elude definitive diagnosis. Serious morbidity or mortality is infrequent. Accurate diagnosis of more obscure causes may help to avoid unnecessary emergency department evaluation and cardiology referral, while also alleviating the concern and stress families and patients experience when dealing with chest pain.

The clinical toxicology of metamfetamine

INTRODUCTION

Metamfetamine is a highly addictive amfetamine analog that acts primarily as a central nervous system (CNS) stimulant. The escalating abuse of this drug in recent years has lead to an increasing burden upon health care providers. An understanding of the drug's toxic effects and their medical treatment is therefore essential for the successful management of patients suffering this form of intoxication.

AIM

The aim of this review is to summarize all main aspects of metamfetamine poisoning including epidemiology, mechanisms of toxicity, toxicokinetics, clinical features, diagnosis, and management.

METHODS

A summary of the literature on metamfetamine was compiled by systematically searching OVID MEDLINE and ISI Web of Science. Further information was obtained from book chapters, relevant news reports, and web material. Epidemiology. Following its use in the Second World War, metamfetamine gained popularity as an illicit drug in Japan and later the United States. Its manufacture and use has now spread to include East and South-East Asia, North America, Mexico, and Australasia, and its world-wide usage, when combined with amfetamine, exceeds that of all other drugs of abuse except cannabis. Mechanisms of toxicity. Metamfetamine acts principally by stimulating the enhanced release of catecholamines from sympathetic nerve terminals, particularly of dopamine in the mesolimbic, mesocortical, and nigrostriatal pathways. The consequent elevation of intra-synaptic monoamines results in an increased activation of central and peripheral α±- and β-adrenergic postsynaptic receptors. This can cause detrimental neuropsychological, cardiovascular, and other systemic effects, and, following long-term abuse, neuronal apoptosis and nerve terminal degeneration. Toxicokinetics. Metamfetamine is rapidly absorbed and well distributed throughout the body, with extensive distribution across high lipid content tissues such as the blood-brain barrier. In humans the major metabolic pathways are aromatic hydroxylation producing 4-hydroxymetamfetamine and N-demethylation to form amfetamine. Metamfetamine is excreted predominantly in the urine and to a lesser extent by sweating and fecal excretion, with reported terminal half-lives ranging from ∼5 to 30 h. Clinical features. The clinical effects of metamfetamine poisoning can vary widely, depending on dose, route, duration, and frequency of use. They are predominantly characteristic of an acute sympathomimetic toxidrome. Common features reported include tachycardia, hypertension, chest pain, various cardiac dysrhythmias, vasculitis, headache, cerebral hemorrhage, hyperthermia, tachypnea, and violent and aggressive behaviour. Management. Emergency stabilization of vital functions and supportive care is essential. Benzodiazepines alone may adequately relieve agitation, hypertension, tachycardia, psychosis, and seizure, though other specific therapies can also be required for sympathomimetic effects and their associated complications.

CONCLUSION

Metamfetamine may cause severe sympathomimetic effects in the intoxicated patient. However, with appropriate, symptom-directed supportive care, patients can be expected to make a full recovery.

Cocaine and beta-blockers: the paradigm

Cocaine is one of the most commonly used substances of abuse. The use of beta-blockers in cocaine induced acute coronary syndrome has long been a matter of debate. While it is widely believed that beta-blockers are contraindicated in cocaine toxicity, there appears to be some recognizable role for certain beta-blockers in ameliorating the cardiovascular as well as central nervous system effects of cocaine. This article explores the role of beta-blockers in the management of cocaine toxicity.

Prevention and reversal by cocaine esterase of cocaine-induced cardiovascular effects in rats

The present study is the first to utilize bacterial cocaine esterase (CocE) to increase elimination of a lethal dose of cocaine and evaluate its cardioprotective effects. Rats received one of 5 treatments: CocE 1 min after saline; CocE 1 min after a lethal i.p. dose of cocaine; saline 1 min after a lethal i.p. dose of cocaine; CocE immediately after observing a cocaine-induced convulsion; and CocE 1 min after observing a cocaine-induced convulsion. Measures were taken of ECG, blood pressure, and cardiac troponin I (cTnI). The specificity of CocE against cocaine was determined by evaluating its actions against the cocaine analogue, WIN-35,065-2, which lacks an ester attack point for CocE. In addition, CocE's effects were compared with those of midazolam, a benzodiazepine often used to manage cocaine overdose. Whereas CocE alone had negligible cardiovascular effects, it blocked or reversed cocaine-induced QRS complex widening, increased QTc interval, ST elevation, bradycardia, and hypertension. When administered 1 min after cocaine, CocE inhibited myocardial damage; however, administered 1 min after a cocaine-induced convulsion (approximately 40s before cocaine-induced death), CocE did not block cTnI release, but did restore cardiac function. Midazolam blocked convulsions, but exhibited inadequate protection against cocaine-induced cardiotoxicity. The majority of rats given cocaine plus midazolam died. CocE did not prevent the lethal cardiovascular effects of WIN-35,065-2. In all likelihood, CocE rapidly and specifically reduced the body burden of cocaine and inhibited or reversed the cardiovascular consequences of high-dose cocaine. These results support CocE as a potential therapeutic avenue in cocaine overdose.

Phentolamine therapy for cocaine-association acute coronary syndrome (CAACS)

INTRODUCTION

The emergency department (ED) evaluation of cocaine-associated acute coronary syndrome (CAACS) is often a diagnostic and therapeutic challenge.

CASE REPORT

We are reporting on the treatment of a patient with cocaine-associated acute coronary syndrome (CAACS) who did not benefit from standard therapy, but who eventually responded positively to phentolamine, an alpha-adrenergic receptor antagonist.

DISCUSSION

This report should encourage physicians to add phentolamine to their pharmacotherapeutic armamentarium in the treatment of CAACS.

Cocaine-induced myocardial infarction

To date, cocaine-induced myocardial infarction (MI) remains an infrequent reason for admission into hospital. However, reports identify rising cocaine usage in the UK. With 7-10% of all patients presenting chest pain having traces of cocaine in their urine, there is an increasing incidence of cardiovascular disease in the under 30s age group. The potential impact on health care resources must cause concern. This report describes the case of a young man admitted to the emergency department after an 18-h cocaine session. With evidence of an anterolateral MI, left heart studies and thrombectomy were undertaken in cardiac catheters. Admission to critical care was required for ongoing respiratory and cardiac support therapies. Although there are many aspects of patient management that can be explored, specific issues to be discussed in this paper include evidence-based treatment options, nursing management of inotrope administration and caring for family and friends.

Crack whips the heart: a review of the cardiovascular toxicity of cocaine

Cocaine is an extremely powerful reinforcing psychostimulant with highly addictive properties. Over the last few decades, cocaine addiction has attained epidemic proportions in North America, imposing a tremendous burden on society and the health care system. The cardiovascular complications of cocaine abuse are adrenergic mediated and range from cocaine-associated acute coronary syndromes to aortic dissection and sudden cardiac death. Concomitant alcohol and cigarette smoking exacerbate the cardiotoxicity of cocaine. This contemporary review discusses the spectrum of cardiac complications arising from cocaine use, operant pathophysiologic mechanisms and controversies surrounding the pharmacotherapy of cocaine-associated acute coronary syndromes.

Central Sympatholysis as a Novel Countermeasure for Cocaine-Induced Sympathetic Activation and Vasoconstriction in Humans

OBJECTIVES

The aim of this study was to determine whether cocaine's sympathomimetic actions can be reversed by a potent centrally acting alpha2 adrenergic receptor (AR) agonist (dexmedetomidine).

BACKGROUND

We recently showed that cocaine stimulates the human cardiovascular system primarily by acting in the brain to increase sympathetic nerve activity (SNA), the neural stimulus to norepinephrine release. Thus, SNA constitutes a putative new drug target to block cocaine's adverse cardiovascular effects at their origin.

METHODS

In 22 healthy cocaine-naïve humans, we measured skin SNA (microneurography) and skin blood flow (laser Doppler velocimetry) as well as heart rate and blood pressure before and after intranasal cocaine (2 mg/kg) alone and in combination with dexmedetomidine or saline.

RESULTS

During intranasal cocaine alone, SNA increased by 2-fold and skin vascular resistance increased from 13.2 +/- 2.3 to 20.1 +/- 2.2 resistance units while mean arterial pressure increased by 14 +/- 3 mm Hg and heart rate by 18 +/- 3 beats/min (p < 0.01). Dexmedetomidine abolished these increases, whereas intravenous saline was without effect. Dexmedetomidine was effective in blocking these sympathomimetic actions of cocaine even in all 7 subjects who were homozygous for the Del322-325 polymorphism in the alpha2C AR, a loss-of-function mutation that is highly enriched in blacks.

CONCLUSIONS

The data advance the novel hypothesis that central sympatholysis with dexmedetomidine constitutes a highly effective countermeasure for cocaine's sympathomimetic actions on the human cardiovascular system, even in individuals carrying the alpha2CDel322-325 polymorphism. (Study to Improve Scientific Understanding of the Cardiovascular Actions of Cocaine; http://clinicaltrials.gov/ct/show/NCT00338546?order=1; NCT00338546).

Cocaine use is associated with an increased risk of stent thrombosis after percutaneous coronary intervention

BACKGROUND

The treatment of cocaine-related acute coronary syndromes presents unique challenges. Although percutaneous coronary intervention in cocaine abusers appears to be safe in the short term, longer-term outcomes have not been reported. We postulated that cocaine use would be associated with increased risk for stent thrombosis.

METHODS

We report 30-day and 9-month clinical outcomes including stent thrombosis, myocardial infarction, repeat revascularization, and death in 71 cocaine abusers who underwent percutaneous coronary intervention at our institution (66 of whom received a stent) compared with 3216 control patients. Propensity score-matched analysis was performed to control for statistical bias present in nonrandomized study populations.

RESULTS

Stent thrombosis occurred in 5 (7.6%) of the 66 stented cocaine abusers during the 9-month follow-up period compared to a 0.6% rate of stent thrombosis in the control database, a highly statistically significant difference (P < .001). In the propensity analysis, stent thrombosis occurred in 4 stented cocaine abusers and 0 of 70 matched controls (6.2% vs 0%; P = .04) throughout the 9-month follow-up period. There was no significant difference in overall rates of myocardial infarction, death, or repeat revascularization at 9 months.

CONCLUSIONS

Because of the increased risk of stent thrombosis, consideration should be given to a more conservative approach in cocaine abusers who present with acute coronary syndromes.