COCAINE USE AND ACUTE MYOCARDIAL INFARCTION

Cocaine Hydrolase Gene Transfer Demonstrates Cardiac Safety and Efficacy against Cocaine-Induced QT Prolongation in Mice

Cocaine addiction is associated with devastating medical consequences, including cardiotoxicity and risk-conferring prolongation of the QT interval. Viral gene transfer of cocaine hydrolase engineered from butyrylcholinesterase offers therapeutic promise for treatment-seeking drug users. Although previous preclinical studies have demonstrated benefits of this strategy without signs of toxicity, the specific cardiac safety and efficacy of engineered butyrylcholinesterase viral delivery remains unknown. Here, telemetric recording of electrocardiograms from awake, unrestrained mice receiving a course of moderately large cocaine doses (30 mg/kg, twice daily for 3 weeks) revealed protection against a 2-fold prolongation of the QT interval conferred by pretreatment with cocaine hydrolase vector. By itself, this prophylactic treatment did not affect QT interval duration or cardiac structure, demonstrating that viral delivery of cocaine hydrolase has no intrinsic cardiac toxicity and, on the contrary, actively protects against cocaine-induced QT prolongation.

Fundamental reaction mechanism and free energy profile for (-)-cocaine hydrolysis catalyzed by cocaine esterase

The fundamental reaction mechanism of cocaine esterase (CocE)-catalyzed hydrolysis of (-)-cocaine and the corresponding free energy profile have been studied by performing pseudobond first-principles quantum mechanical/molecular mechanical free energy (QM/MM-FE) calculations. On the basis of the QM/MM-FE results, the entire hydrolysis reaction consists of four reaction steps, including the nucleophilic attack on the carbonyl carbon of (-)-cocaine benzoyl ester by the hydroxyl group of Ser117, dissociation of (-)-cocaine benzoyl ester, nucleophilic attack on the carbonyl carbon of (-)-cocaine benzoyl ester by water, and finally dissociation between the (-)-cocaine benzoyl group and Ser117 of CocE. The third reaction step involving the nucleophilic attack of a water molecule was found to be rate-determining, which is remarkably different from (-)-cocaine hydrolysis catalyzed by wild-type butyrylcholinesterase (BChE; where the formation of the prereactive BChE-(-)-cocaine complex is rate-determining) or its mutants containing Tyr332Gly or Tyr332Ala mutation (where the first chemical reaction step is rate-determining). Besides, the role of Asp259 in the catalytic triad of CocE does not follow the general concept of the "charge-relay system" for all serine esterases. The free energy barrier calculated for the rate-determining step of CocE-catalyzed hydrolysis of (-)-cocaine is 17.9 kcal/mol, which is in good agreement with the experimentally derived activation free energy of 16.2 kcal/mol. In the present study, where many sodium ions are present, the effects of counterions are found to be significant in determining the free energy barrier. The finding of the significant effects of counterions on the free energy barrier may also be valuable in guiding future mechanistic studies on other charged enzymes.

Undisclosed cocaine use and chest pain in emergency departments of Spain

Aims

Illicit cocaine consumption in Spain is one of the highest in Europe. Our objective was to study the incidence of undisclosed cocaine consumption in patients attending in two Spanish Emergency Departments for chest pain.

Methods

We analysed urine samples from consenting consecutive patients attending ED for chest pain to determine the presence of cocaine, and other drugs, by semiquantative tests with fluorescence polarization immunoassay (FPIA).

Results

Of 140 cases, 15.7 presented positive test for drugs, and cocaine was present in 6.4%. All cocaine-positive patients were younger (p < 0.001); none was admitted to Hospital (p = 0.08). No significant differences in ED stay or need for hospitalization were found between cocaine-positive and negative patients.

Conclusion

This finding in chest pain patients who consented to urine analysis suggests that the true incidence of cocaine use leading to such ED visits may be higher.

Incidence and impact of undisclosed cocaine use in emergency department chest pain and trauma patients

Background

One of the highest rates of illicit cocaine consumption in Europe is in Spain. Our objective was to study the incidence and impact of undisclosed cocaine consumption in patients attending the emergency department (ED) for trauma or chest pain.

Methods

We analysed urine samples from consecutive patients attending the ED for trauma or chest pain to determine the presence of cocaine, cannabis, amphetamine/metaamphetamine and opioids by semiquantative tests with fluorescence polarization immunoassay (FPIA).

Results

Thirty percent of eligible patients participated. Of 75 cases, 61.3% had trauma and 38.7% chest pain; 25% presented a positive test for drugs. Cocaine was present in 13.3% and cannabis in the same proportion. No differences were found regarding positive cocaine test and chief complaint, ED or hospital stay, or additional tests. Cocaine-positive patients were significantly younger.

Evaluation of patients with methamphetamine- and cocaine-related chest pain in a chest pain observation unit

OBJECTIVE

Risk of acute coronary events in patients with methamphetamine and cocaine intoxication has been described. Little is known about the need for additional evaluation in these patients who do not have evidence of myocardial infarction after the initial emergency department evaluation. We herein describe our experience with these patients in a chest pain unit (CPU) and the rate of cardiac-related chest pain in this group.

METHODS

Retrospective analysis of patients evaluated in our CPU from January 1, 2000 to December 16, 2004 with a history of chest pain. Patients who had a positive urine toxicologic screen for methamphetamine or cocaine were included. No patients had ECG or cardiac injury marker evidence of myocardial infarction or ischemia during the initial emergency department evaluation. A diagnosis of cardiac-related chest pain was based upon positive diagnostic testing (exercise stress testing, nuclear perfusion imaging, stress echocardiography, or coronary artery stenosis >70%).

RESULTS

During the study period, 4568 patients were evaluated in the CPU. A total of 1690 (37%) of patients admitted to the CPU underwent urine toxicologic testing. The result of urine toxicologic test was positive for cocaine or methamphetamine in 224 (5%). In the 2871 patients who underwent diagnostic testing for coronary artery disease (CAD), 401 (14%) were found to have positive results. There was no difference in the prevalence of CAD between those with positive result for toxicology screens (26/156, 17%) and those without (375/2715, 13%, RR 1.2, 95% CI 0.8-1.7).

CONCLUSION

These findings suggest a relatively high rate of CAD in patients with methamphetamine and cocaine use evaluated in a CPU.

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 chest pain

Cocaine-associated chest pain is a clinical entity that crosses all socioeconomic groups and hence will be encountered by many physicians. The initial evaluation and treatment of cocaine-induced chest pain are similar to those of patients who have non-cocaine-induced chest pain, but there are several notable exceptions. This article reviews the pathophysiology, evaluation, management, and disposition decisions unique to patients presenting with cocaine-induced chest pain.

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.

Cocaine-associated chest pain

The pathophysiology of cocaine leading to myocardial ischemia is multifactorial. Given the paucity of well-designed clinical studies, treatment is directed toward the potential mechanisms involved in the development of myocardial ischemia. Fortunately, morbidity and mortality in this patient population are low, and the vast majority of patients will not suffer AMI or other cardiac complications. Long-term prognosis is excellent for those who abstain from continued cocaine use.

Peripartum care of the cocaine-abusing parturient: are we ready?

Cocaine abuse in the United States is widespread, affecting more than 30 million people. Nearly 90% of cocaine-abusing women are of childbearing age. Cardiovascular complications of cocaine intoxication include dysrhythmias, ischemia and/or infarction, and account for most cocaine-related deaths. Pregnancy enhances the cardiovascular toxicity of cocaine. While the epidemiology, pathophysiology, clinical symptomatology and implications on pregnancy of cocaine addiction in pregnancy have received significant attention over the past 25 years, far too little attention has been given to the therapeutic considerations and peripartum care of the cocaine-abusing parturients. The timely treatment of acute cocaine-induced cardiovascular toxicity in pregnancy is by far the best predictor of good maternal and fetal outcome. However, no specific treatment guidelines are currently available for cocaine-induced cardiac dysrhythmias. This article discusses briefly several agents (and considers their mechanism of action) that have been proposed for the treatment of chest pain and other cardiovascular side-effects of cocaine toxicity in pregnancy.

Selection of 2?-Fluoro-modified RNA Aptamers for Alleviation of Cocaine and MK-801Inhibition of the Nicotinic Acetylcholine Receptor

The nicotinic acetylcholine receptor (nAChR) belongs to a group of five structurally related proteins that regulate signal transmission between approximately 10(12) cells of the mammalian nervous system. Many therapeutic agents and abused drugs inhibit the nAChR, including the anti-convulsant MK-801 and the abused drug cocaine. Many attempts have been made to find compounds that prevent inhibition by cocaine. Use of transient kinetic techniques to investigate the inhibition of the receptor by MK-801 and cocaine led to an inhibition mechanism not previously proposed. The mechanism led to the development of combinatorially synthesized RNA ligands that alleviate inhibition of the receptor. However, these ligands are relatively unstable. Here we determined whether much more stable 2'-fluoro-modified RNA ligands can be prepared and used to study the alleviation of receptor inhibition. Two classes of 2'-fluoro-modified RNA ligands were obtained: One class binds with higher affinity to the cocaine-binding site on the closed-channel form and, as predicted by the mechanism, inhibits the receptor. The second class binds with equal or higher affinity to the cocaine-binding site on the open-channel form and, as predicted by the mechanism, does not inhibit the receptor, and does alleviate cocaine and MK-801 inhibition of the nAChR. The stability of these 2'-fluoro-RNAs expands the utility of these ligands.