Putting cocaine use and cocaine-associated cardiac arrhythmias into epidemiological and clinical perspective

The association between regular cocaine use, with and without tobacco co-use, and adverse cardiovascular and respiratory outcomes

BACKGROUND

Understanding the potential impact of cocaine use on health is increasingly important as cocaine use rises in the U.S.

OBJECTIVES

This study evaluated the associations of regular cocaine use, with and without tobacco co-use, with cardiovascular and respiratory outcomes.

METHODS

Analysis of a limited dataset obtained through IBM Watson Health Explorys, a platform integrating electronic health record data. Matched controls were defined for: 1) cocaine-using patients (n = 8244; 44 % female); and subgroups of cocaine-using patients: 2) with an encounter diagnosis for tobacco use disorder (TUD; n = 4706); and 3) without a TUD diagnosis (non-TUD; n = 3538). Patients had at least one documented medical evaluation in the MetroHealth System (Cleveland, Ohio). Cocaine-using patients had an encounter diagnosis of cocaine abuse/dependence and/or ≥2 cocaine-positive drug screens. Control patients, with no documented cocaine-use, were matched to the cocaine-using patients on demographics, residential zip code median income, body mass index, and, for the total sample, TUD-status. Outcomes were encounter diagnosis (yes/no) of cerebrovascular accident, heart arrhythmia, myocardial infarction, subarachnoid hemorrhage, asthma, chronic obstructive pulmonary disease (COPD), pneumonia, and all-cause mortality.

RESULTS

TUD-patients had the greatest prevalence of cardiovascular and respiratory disease, regardless of cocaine-use indication. In the total sample, TUD, and non-TUD subgroups, regular cocaine use was significantly associated with greater risk for cerebrovascular accident, arrhythmia, myocardial infarction, asthma, COPD, pneumonia and mortality.

CONCLUSIONS

Cocaine use is associated with significantly greater risk of adverse cardiovascular and respiratory diagnoses and all-cause mortality.

Addictive drugs, arrhythmias, and cardiac inward rectifiers

In many addictive drugs including alcohol and nicotine, proarrhythmic effects were reported. This review provides an overview of the current knowledge in this field (with a focus on the inward rectifier potassium currents) to promote the lacking data and appeal for their completion, thus, to improve understanding of the proarrhythmic potential of addictive drugs.

Cocaine-related health emergencies in Europe: a review of sources of information, trends and implications for service development

BACKGROUND

Cocaine-related health consequences are difficult to observe. Data on drug users in health-emergency settings may be a useful source of information on consequences that are not visible via other information sources.

METHODS

Thirty European countries submit an annual national report on the drug situation to the EMCDDA. All reports for the period 2007-2010 were analyzed, with particular attention given to auditing cocaine-related mentions. Analysis was also performed in order to identify sources and case definitions, assess coverage, audit cases and, where possible, to identify long-term trends.

RESULTS

Considerable heterogeneity existed between countries in their approach to recording drug-related emergencies, with only Spain and the Netherlands having established formal indicators. The highest annual numbers of cocaine-related episodes were reported by the UK (3,502), Spain (2,845) and the Netherlands (1,211). A considerable (2- to 3-fold) increase in the numbers of cocaine-related episodes has been reported since the end of the 1990s in these countries; these increases peaked in Spain and England around 2007/08.

CONCLUSIONS

The analysis reported here suggests the need to develop more standardized approaches to monitoring drug-related emergencies. It points to the potential value of developing effective referral links between the emergency and specialized drug services working with cocaine users.

Cocaine administration increases angiotensin I-converting enzyme (ACE) expression and activity in the rat striatum and frontal cortex

Some central effects of cocaine administration seem to be related to angiotensin II (Ang II) or its metabolites. Nonetheless, it is still an open question whether or not the levels of angiotensin I-converting enzyme (ACE), the main Ang II generating enzyme, are modified by cocaine administration. To evaluate the effect of acute and subchronic cocaine administration on ACE activity and mRNA expression, male rats were randomly assigned to saline or cocaine group. Acute and subchronic cocaine administration induced a significant increase in ACE activity and mRNA expression in the frontal cortex and striatum but not in the hippocampus. These results suggest that some of the Ang II related effects of cocaine upon the central nervous system can be mediated by changes on the expression and activity of ACE in the striatum and frontal cortex.

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.

Role of voltage-gated sodium, potassium and calcium channels in the development of cocaine-associated cardiac arrhythmias

Cocaine is a highly active stimulant that alters dopamine metabolism in the central nervous system resulting in a feeling of euphoria that with time can lead to addictive behaviours. Cocaine has numerous deleterious effects in humans including seizures, vasoconstriction, ischaemia, increased heart rate and blood pressure, cardiac arrhythmias and sudden death. The cardiotoxic effects of cocaine are indirectly mediated by an increase in sympathomimetic stimulation to the heart and coronary vasculature and by a direct effect on the ion channels responsible for maintaining the electrical excitability of the heart. The direct and indirect effects of cocaine work in tandem to disrupt the co-ordinated electrical activity of the heart and have been associated with life-threatening cardiac arrhythmias. This review focuses on the direct effects of cocaine on cardiac ion channels, with particular focus on sodium, potassium and calcium channels, and on the contributions of these channels to cocaine-induced arrhythmias. Companion articles in this edition of the journal examine the epidemiology of cocaine use (Wood & Dargan) and the treatment of cocaine-associated arrhythmias (Hoffmann).