Experience with esmolol for the treatment of cocaine-associated cardiovascular complications

The ASAM/AAAP Clinical Practice Guideline on the Management of Stimulant Use Disorder

The American Society of Addiction Medicine/American Academy of Addiction Psychiatry (ASAM/AAAP) Clinical Practice Guideline on the Management of Stimulant Use Disorder provides guidance on evidence-based strategies for the treatment of stimulant use disorders (StUDs), stimulant intoxication, and stimulant withdrawal, as well as secondary and tertiary prevention of harms associated with stimulant use. The Clinical Guideline Committee (CGC) comprised experts from ASAM and AAAP representing a range of clinical settings and patient populations. The guideline was developed following modified GRADE methodology. The process included a systematic literature review as well as several targeted supplemental searches. The CGC utilized Evidence to Decision tables to review available evidence and rate the strength of each recommendation. The clinical practice guideline was revised based on external stakeholder review. Key takeaways included: Contingency management represents the current standard of care for treatment of StUDs; Pharmacotherapies may be utilized off-label to treat StUDs; Acute stimulant intoxication can result in life-threatening complications that should be addressed in an appropriate level of care; Secondary and tertiary prevention strategies should be used to reduce harms related to risky stimulant use.

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.

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.

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.

Comparison of Frequency of Cardiovascular Events and Mortality in Patients With Heart Failure Using Versus Not Using Cocaine

Beta-blocker treatment improves left ventricular function, morbidity, and survival in patients with systolic heart failure (HF). However, there are limited data addressing the safety and efficacy of β blockers in the setting of cocaine use as there is a perceived risk of adverse outcomes. Our aim was to determine if beta-blocker treatment was safe in HF patients with a history of cocaine use compared with HF patients without history of cocaine use. We also examined whether effects differed between cardioselective versus noncardioselective β blockers. Ninety systolic HF patients with cocaine use were compared with 177 patients with nonischemic, systolic HF, and no cocaine use. Outcomes were HF readmissions, major adverse cardiovascular events, and death using multivariable Cox proportional hazard models adjusted for age, black race, hypertension, diabetes, coronary artery disease, renal insufficiency, and angiotensin-converting enzyme inhibitors. Beta-blocker treatment in systolic HF patients with cocaine use did not have significant differences in HF readmissions (hazard ratio [HR] 0.66, 95% CI 0.31 to 0.1.38), major adverse cardiovascular events (HR 0.58, 95% CI 0.27 to 1.09), death (HR 0.96, 95% CI 0.39 to 2.34), or all combined outcomes (HR 0.76, 95% CI 0.39 to 1.47) compared with beta-blocker treatment in HF patients without cocaine use. Within HF patients with cocaine use, mortality rates (HR 1.50, 95% CI 0.28 to 8.23) were not significantly different between patients treated with noncardioselective versus cardioselective β blockers. In conclusion, beta-blocker treatment in systolic HF patients with cocaine use was not associated with adverse outcomes.

β-Blockers, Cocaine, and the Unopposed α-Stimulation Phenomenon

Cocaine abuse remains a significant worldwide health problem. Patients with cardiovascular toxicity from cocaine abuse frequently present to the emergency department for treatment. These patients may be tachycardic, hypertensive, agitated, and have chest pain. Several pharmacological options exist for treatment of cocaine-induced cardiovascular toxicity. For the past 3 decades, the phenomenon of unopposed α-stimulation after β-blocker use in cocaine-positive patients has been cited as an absolute contraindication, despite limited and inconsistent clinical evidence. In this review, the authors of the original studies, case reports, and systematic review in which unopposed α-stimulation was believed to be a factor investigate the pathophysiology, pharmacology, and published evidence behind the unopposed α-stimulation phenomenon. We also investigate other potential explanations for unopposed α-stimulation, including the unique and deleterious pharmacologic properties of cocaine in the absence of β-blockers. The safety and efficacy of the mixed β-/α-blockers labetalol and carvedilol are also discussed in relation to unopposed α-stimulation.

Should β-Blockers Be Used in the Treatment of Cocaine-Associated Acute Coronary Syndrome?

Objective:

To critically evaluate the 30 year debate of β-blocker use in cocaine-induced acute coronary syndrome (CIACS).

Data Sources:

An Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, and Ovid MEDLINE (1966–August 21, 2007) search of the medical literature was conducted using the key terms cocaine, myocardial infarction, acute coronary syndrome, and adrenergic β-antagonists.

Study Selection and Data Extraction:

All clinical trials, case reports, national cardiovascular guidelines, and reviews published in English were evaluated. Case reports were included based on whether (1) acute coronary syndrome was suspected, (2) a β-blocker was used during the treatment course, and (3) objective and subjective patient-specific information was documented.

Data Synthesis:

Three case reports and 2 placebo-controlled trials were identified that used 4 β-blockers (atenolol, labetalol, metoprolol, propranolol). Three national guidelines addressed β-blocker use. Although published data are limited, propranolol and labetalol exert minimal to no effect on alleviating cocaine-induced coronary vasoconstriction. None of the evaluated national guidelines recommends β-blockers as first-line agents in CIACS management.

Conclusion:

β-Blockers should not be considered first-line agents for controlling chest pain in patients with documented CIACS. If long-term β-blockade is warranted, its benefits should be weighed against recurrent use of cocaine and possible exacerbation of acute coronary syndrome. Given that carvedilol exhibits ancillary pharmacologic proprieties beneficial in CIACS, and post-myocardial infarction mortality data are available regarding its use, this agent could be considered to be appropriate therapy.

Current strategies in the evaluation and management of cocaine-induced chest pain

With each successive year, the number of Emergency Department (ED) visits related to illicit drug abuse has progressively increased. Cocaine is the most common illegal drug to cause a visit to the ED. Cocaine use results in a variety of pathophysiological changes with regards to the cardiovascular system, such as constriction of coronary vessels, dysfunction of vascular endothelium, decreased aortic elasticity, hemodynamic disruptions, a hypercoagulable state, and direct toxicity to myocardial and vascular tissue. The clinical course of patients with cocaine-induced chest pain (CCP) is often challenging, and electrocardiographic findings can be potentially misleading in terms of diagnosing a myocardial infarction. In addition, there is no current satisfactory study regarding outcomes of use of various pharmacological drug therapies to manage CCP. At present, calcium-channel blockers and nitroglycerin are two pharmacological agents that are advocated as first-line drugs for CCP management, although the role of labetalol has been controversial and warrants further investigation. We performed an extensive search of available literature through a large number of scholarly articles previously published and listed on Index Medicus. In this review, we put forward a concise summary of the current approach to a patient presenting to the ED with CCP and management of the clinical scenario. The purpose of this review is to summarize the understanding of cocaine's cardiovascular pathophysiology and to examine the current approach for proper evaluation and management of CCP.

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.

Controversial therapeutics: the β-adrenergic antagonist and cocaine-associated cardiovascular complications dilemma

Cocaine abuse is associated with cardiovascular complications that include chest pain and myocardial infarction. Traditional therapy for these conditions includes a β-adrenergic antagonist. However, guidelines released in 2008 recommended against this treatment option because of the prevailing theory that cocaine will potentiate vasospasm secondary to unopposed α-adrenergic effects. Subsequently, further evidence and updated guidelines have become available, debunking this claim. Current literature is limited but suggests that β-adrenergic antagonists are harmful. Although case reports support a detrimental effect of β-adrenergic antagonists, the anecdotal data are inconsistent, and the conclusions from case studies are overruled by larger studies. The pharmacology, pathophysiology, and literature on the use of β-adrenergic antagonists in association with cocaine are reviewed. Future studies that focus on outcomes and different pharmacologic profiles of β-adrenergic antagonists are needed.

Evaluation of the hydrolytic activity of a long-acting mutant bacterial cocaine in the presence of commonly co-administered drugs

BACKGROUND

Cocaine toxicity is a prevalent problem in the Unites States for which there is currently no FDA-approved pharmacotherapy. We have developed a bacterial cocaine esterase (CocE) towards this indication. A thermostabilized mutant of CocE (DM-CocE) retains the hydrolytic activity of the wild-type esterase, rapidly hydrolyzing cocaine into the inactive metabolites ecgonine methyl ester and benzoic acid, and can prevent cocaine toxicities in rodent and non-human primate models. To advance DM-CocE towards clinical use, we examine here how the hydrolytic activity of DM-CocE is altered by some drugs commonly co-administered with cocaine.

METHODS

We employed a spectrophotometric cocaine hydrolysis assay to evaluate whether pharmacologically relevant doses of alcohol, nicotine, morphine, phencyclidine, ketamine, methamphetamine, naltrexone, naloxone, or midazolam would alter the Michaelis-Menten kinetics of DM-CocE for cocaine. Mass spectrometry was used to evaluate interaction with diazepam as this drug interferes with the absorbance spectra of cocaine critical for the spectrophotometric assay.

RESULTS

Alcohol, nicotine, morphine, phencyclidine, ketamine, methamphetamine, naltrexone, naloxone, and midazolam did not alter cocaine hydrolysis by DM-CocE. However, diazepam significantly slowed DM-CocE cocaine hydrolysis at very high concentrations, most likely through interaction of the phenyl ring of the benzodiazepine with the active site of DM-CocE.

CONCLUSIONS

DM-CocE does not display significant drug interactions, with the exception of diazepam, which may warrant further study as DM-CocE progresses towards a clinically used pharmacotherapy for cocaine toxicity. Alternate benzodiazepines, e.g., midazolam could be used to avoid this potential interaction.

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.

Treatment of patients with cocaine-induced arrhythmias: bringing the bench to the bedside

Widespread use of cocaine and its attendant toxicity has produced a wealth of benchwork studies and small animal investigations that evaluated the effects of cocaine on the cardiovascular system. Despite this wealth of knowledge, very little is known about the frequency or types of arrhythmias in patients with significant cocaine toxicity. The likely aetiologies; catecholamine excess, sodium channel blockade, potassium channel blockade, calcium channel effects, or ischaemia may act alone or in concert to produce a vast array of clinical findings that are modulated by hyperthermia, acidosis, hypoxia and electrolyte abnormalities. The initial paper in the series by Wood & Dargan providing the epidemiological framework of cocaine use and abuse is followed by a detailed review of the electrophysiological effects of cocaine by O'Leary & Hancox. This review is designed to complement the previous papers and focuses on the diagnosis and treatment of patients with cocaine-associated arrhythmias.

Effects of labetalol on hemodynamic parameters and soluble biomarkers of inflammation in acute coronary syndrome in patients with active cocaine use

Cocaine use is associated with increased cardiovascular mortality and can promote acute coronary syndrome (ACS). Use of beta-blockers is controversial in patients who use cocaine, and the safety and efficacy of these medications in ACS in patients actively using cocaine is unknown. We enrolled 90 patients with ACS and positive urine drug screen for cocaine. Patients received standard ACS therapy plus either labetalol (n = 60) or diltiazem (n = 30). Blood pressure and heart rate were measured at baseline and 48 hours. Levels of serum CD40 ligand, interleukin (IL)-6, and choline at baseline and 48 hours were determined. There were no baseline differences in hemodynamics or serum levels of inflammatory markers between the labetalol and diltiazem groups. Both groups experienced a significant and equivalent decrease in BP and HR at 48 hours compared with baseline. At 48 hours of treatment, there were significant decreases of 17% in CD40 ligand (P < .005) and 16% in IL-6 (P < .005) but no change in choline in the diltiazem group. Furthermore, in the labetalol group, there were significant differences of 30% in CD40 ligand (P < .005 time and group comparison), 22% in IL-6 (P < .005 time and group comparison), and 18% in choline (P < .005 time and group comparison). There were no adverse events during hospitalization in any patients who received labetalol. In conclusion, labetalol appears to be safe in cocaine-associated ACS. Furthermore, labetalol provides a beneficial hemodynamic response and, in comparison to diltiazem, potentiates an anti-inflammatory vascular response in this setting.

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.

Death temporally related to the use of a Beta adrenergic receptor antagonist in cocaine associated myocardial infarction

INTRODUCTION

Although it is commonly stated that the use of beta adrenergic receptor antagonists is contraindicated in patients with cocaine toxicity, actual clinical evidence of harm is lacking. This case helps to highlight the risks of beta adrenergic receptor antagonists in patients with chest pain associated with cocaine use.

CASE REPORT

A 54-year-old man was brought to the emergency department (ED) complaining of chest pain after using approximately 1 gram of intranasal cocaine. Aspirin and nitroglycerin spray relieved his pain. Although he remained pain free, tachycardia persisted despite 15 mg of diazepam intravenously. Nearly two hours after presentation, a total of 5 mg of metoprolol was given for persistent tachycardia (115/minute) and an elevated troponin. Shortly thereafter, the patient complained of crushing substernal chest pain, developed pulseless electrical activity, and could not be resuscitated.

DISCUSSION

The administration of beta adrenergic receptor antagonists exacerbates cocaine-induced lethality in animals. In humans given smaller doses of cocaine, beta adrenergic receptor antagonists exacerbate coronary vasoconstriction. Both effects are presumed to occur through unopposed alpha adrenergic receptor agonism. Despite these data, actual cases describing adverse effects in cocaine users given beta adrenergic receptor antagonists are uncommon. This case supports the potential lethality of a cocaine-beta adrenergic receptor antagonist interaction.

Prevalence of cocaine use in ED patients with severe hypertension

STUDY OBJECTIVE

We prospectively evaluated the prevalence of cocaine use in emergency department patients with elevated diastolic blood pressure greater than 120 mm Hg.

DESIGN

Urine was collected on adult patients with diastolic blood pressure greater than 120 mm Hg. The Institutional Review Board granted a waiver of informed consent based on complete deidentification of the data to prevent selection bias. Spontaneously voided urine specimens were analyzed for the presence of the benzoylecgonine.

RESULTS

Of 107 eligible patients with a diastolic blood pressure equal to or greater than 120 mm Hg, 99 were tested. Of the 99, 13 (13%) tested positive, and of which, 6 (46%) presented with a request for medication refill. Five patients (39%) had cardiovascular and/or pulmonary complaints.

CONCLUSION

Emergency department patients with hypertension who have recently used cocaine may be difficult to differentiate from those who have not. Consideration should be given to the potential for cocaine use when making treatment decisions in patients with hypertension.

Evaluation and Management of the Patient Who Has Cocaine-associated Chest Pain

Patients who have chest pain following the use of cocaine have become more common in emergency departments throughout the United States,with approximately 6% of these patients sustaining an acute MI. The authors have described the rationale for recommending aspirin, benzodiaze-pines, and nitroglycerin as first-line treatments and calcium-channel blockade or phentolamine as possible second-line therapies and have summarized the controversies surrounding the use of fibrinolytic agents. Admission for observation is one reasonable approach to the management of the low-risk cohort. Evaluation for underlying coronary artery disease is reasonable, particularly in patients who have acute MI. Patients who do not have infarction can undergo evaluation for possible coronary artery disease on an outpatient basis. Routine interventions for secondary prophylaxis as well as cocaine rehabilitation should be used in this patient population, because the long-term prognosis seems somewhat dependent upon the ability of the patient to discontinue cocaine use.

Cocaine-associated chest pain

Current estimates establish that more than 30 million people in the United States use cocaine. Cardiovascular complaints commonly occur among patients who present to emergency departments(EDs) after cocaine use, with chest pain the most common complaint in several studies. Although myocardial ischemia and infarction account for only a small percentage of cocaine-associated chest-pain, physicians must understand the pathophysiology of cocaine and appropriate diagnostic and treatment strategies to best manage these patients and minimize adverse outcomes. This article reviews the pharmacology of cocaine, its role in the pathogenesis of chest pain with specific emphasis on inducing myocardial ischemia and infarction, and current diagnostic and management strategies for cocaine-associated chest pain encountered in the ED.

Street drug abuse leading to critical illness

Critical care physicians are frequently confronted with intoxicated patients who have used street drugs. In the last decade there has been an upward trend in the use of these substances, particularly amongst adolescents and young adults in large urban areas. In excess quantities all street drugs can lead to critical illness. Early and appropriate medical attention by emergency medicine physicians and intensivists can improve outcomes. In this review article we intend to familiarize critical care physicians with the most common street drugs such as amphetamines, ecstasy, cocaine, gamma hydroxybutyrate, opioids, and phencyclidine.

Toxicology in the critically ill patient

Intoxications present in many forms including: known drug overdose or toxic exposure, illicit drug use, suicide attempt, accidental exposure, and chemical or biological terrorism. A high index of suspicion and familiarity with toxidromes can lead to early diagnosis and intervention in critically ill, poisoned patients. Despite a paucity of evidence-based information on the management of intoxicated patients, a rational and systematic approach can be life saving.

COCAINE USE AND ACUTE MYOCARDIAL INFARCTION

Cocaine use in the United States is widespread, affecting more than 30 million Americans. Although many of these persons do not seek healthcare, the overriding cause for hospitalization is cocaine-associated chest pain. Because only a minority of these patients suffer myocardial injury, it is important to exclude even rarer life-threatening causes for chest pain, such as aortic dissection or pneumothorax. Following that, a thorough knowledge of the pathophysiology and existing literature helps to provide cost-effective care, which focuses resources on those patients most likely to suffer complications. Regardless of the severity of complications, referral to cocaine detoxification programs, counseling, social support, and outpatient follow-up care for modification of cardiac risk factors is a fundamental component of long-term patient care.

Part 8: advanced challenges in resuscitation. Section 2: toxicology in ECC. European Resuscitation Council

Use of standard ACLS protocols for all patients who are critically poisoned may not result in an optimal outcome. Care of severely poisoned patients can be enhanced by urgent consultation with a medical toxicologist. Alternative approaches required in severely poisoned patients include: o Higher doses than usual. o Drugs that are rarely used to treat cardiac arrest (amrinone, calcium, esmolol, glucagon, insulin, labetalol, phenylephrine, physostigmine, and sodium bicarbonate). o Heroic measures, such as prolonged CPR and use of circulatory assist devices. When resuscitation is unsuccessful, organ donation may still be an option.

Butyrylcholinesterase: an enzyme antidote for cocaine intoxication

Cocaine-associated toxicity is the result of effects on the cardiovascular and central nervous systems. Since the primary route of cocaine inactivation is enzymatic degradation by butyrylcholinesterase (BChE), we sought to determine if the administration of purified human enzyme would ameliorate the lethal effects of cocaine. While the cardiovascular, autonomic or central nervous systems were unaffected by BChE, the enzyme reduced the adverse effects of cocaine including hypertension, hyperactivity and convulsions. BChE decreased both the brain and blood levels of cocaine and shifted the metabolites towards the production of the inactive product ecgonine methyl ester and away from the physiologically active metabolites, norcocaine and benzoylecgonine. We conclude that BChE would appear to be an ideal antidote in the treatment of cocaine intoxication and has potential therapeutic application.

Evaluation of patients with chest pain after cocaine use

Cocaine remains the most common cause of illicit drug-related visits to emergency departments, 40% of which result from chest pain. It is estimated that over half of the 64,000 patients evaluated annually for cocaine-associated chest pain will be admitted to hospitals for the evaluation of myocardial ischemia or infarction, at a health care cost of over eighty million dollars. Although the link between cocaine use and myocardial ischemia is well established, only about 6% of patients with cocaine-associated chest pain will demonstrate biochemical evidence of myocardial infarction. This article focuses on the evaluation of patients with chest pain following cocaine use, and concentrates on ways to improve diagnosis, management, and utilization of health care services.

Therapeutic use of butyrylcholinesterase for cocaine intoxication

The most common complications of cocaine ingestion are on the cardiovascular and central nervous systems and produce chest pain and generalized seizures. In humans, decreased levels of butyrylcholinesterase (BChE) (EC 3.1.1.8) have been associated with sustained effects of cocaine and life-threatening complications. Administration of purified human BChE has previously been demonstrated to protect against cocaine-associated cardiovascular toxicity in rats. A shift in the metabolism of cocaine as well as enhanced metabolism may be the underlying mechanism of the enzyme. Therefore, levels of the parent drug and four metabolites were determined in rat plasma after i.p. administration of a lethal cocaine dose, followed by i.v. administration of BChE. Plasma and brain concentrations of cocaine were lowered by 80% after BChE administration. Furthermore, the metabolic profile of cocaine in the plasma was altered. The concentration of ecgonine methylester was doubled although the concentration of ecgonine, a secondary metabolite of cocaine, was reduced. The level of benzoylecgonine was reduced by one-half while norcocaine was absent. Cocaine-associated effects upon the central nervous system were also shown to be reduced by administration of BChE to conscious rats. Furthermore, our studies in the cat have also shown that purified BChE shifts the metabolic profile of cocaine (1 mg/kg) to the pharmacologically inactive products ecgonine methylester and ecgonine. Pretreatment with BChE (0.27, 1.0, and 10.0 mg/kg) ameliorated the hypertensive effects of cocaine (1 mg/kg) by reducing the duration and the extent of BP elevation by 66%. Administration of the enzyme, 1 min after cessation of cocaine infusion, resulted in an immediate attenuation in the cocaine-induced broadening of the QRS complex. These results suggest that BChE could be an effective and rapid therapy for the treatment of life-threatening cocaine-induced cardiovascular effects in human while clearing the total body burden of cocaine.

Clinical safety of lidocaine in patients with cocaine-associated myocardial infarction

STUDY OBJECTIVE

To evaluate the safety of lidocaine in the setting of cocaine-induced myocardial infarction (MI).

DESIGN

A retrospective, multicenter study.

SETTING

Twenty-nine university, university-affiliated, or community hospitals during a 6-year period (total of 117 cumulative hospital-years).

PARTICIPANTS

Patients with cocaine-associated MI who received lidocaine in the emergency department.

RESULTS

Of 29 patients who received lidocaine in the setting of cocaine-associated MI, no patient died; exhibited bradydysrhythmias, ventricular tachycardia, or ventricular fibrillation; or experienced seizures after administration of lidocaine (95% confidence interval, 0% to 11%).

CONCLUSION

Despite theoretical concerns that lidocaine may enhance cocaine toxicity, the use of lidocaine in patients with cocaine-associated MI was not associated with significant cardiovascular or central nervous system toxicity.

Chest pain associated with cocaine: an assessment of prevalence in suburban and urban emergency departments

STUDY OBJECTIVE

Chest pain and myocardial infarction following the use of cocaine have been well documented. We assessed the prevalence of cocaine use in patients who presented to the emergency department with chest pain of possibly ischemic origin.

DESIGN

During times of research assistant availability, consecutive adults with the chief complaint of chest pain unexplained by trauma or radiographic abnormality were questioned about cocaine use in the preceding week. Urine was tested for the presence of cocaine or cocaine metabolites with a highly accurate bedside urine test kit (specificity, 100%; sensitivity 98%). Anonymous unlinked data-collection methods were used. Therefore we could not determine whether the patients who used cocaine had sustained myocardial infarctions.

SETTING

One suburban and three urban EDs.

RESULTS

We enrolled 359 patients with a mean age of 51 years, 8% of whom sustained myocardial infarctions. Sixty patients (17%) had cocaine or cocaine metabolites in urine. The likelihood of testing positive for cocaine varied by age group: 18 to 30 years, 29%; 31 to 40 years, 48%; 41 to 50 years, 18%; 51 to 60 years, 3%; 61 years or older, 0% (P < .0001). Of the 60 patients who tested positive for cocaine, only 43 (72%) admitted recent use.

CONCLUSION

Many ED patients with chest pain have recently used cocaine. Because the recent use of cocaine is not uncommon in patients with chest pain up to 60 years old, such patients should be questioned about cocaine use. When treatment or disposition may be altered, consideration should be given to objective assessment of cocaine use because patient self-report does not appear reliable.