Alcohol plus cocaine: the whole is more than the sum of its parts

Increased picture-word interference in chronic and recreational users of cocaine

OBJECTIVE

The correct production of speech depends on the effective use of inhibitory control. Cocaine abuse has been linked to impaired inhibition in the verbal and nonverbal domains. The aim of this study was to evaluate the possible impairment of the inhibitory control process engaged in the production of language among chronic cocaine users, both in rehabilitation and recreational contexts.

METHOD

Researchers obtained an index of semantic interference from a picture-word task performed by chronic cocaine users in rehabilitation (Experiment 1) and recreational cocaine polydrug users (Experiment 2). Cocaine users in both groups were matched for age and intelligence with cocaine-free health controls. Performance on the picture-word task was analyzed by repeated-measures analyses of variance.

RESULTS

Both groups of cocaine users showed significantly more semantic interference than their respective cocaine-free control group. These results suggest a deficit in the ability to inhibit interfering information.

CONCLUSIONS

The present findings suggest that cocaine use, even at recreational levels, is associated with specific impairments in the inhibitory mechanism that reduces the activation of overt competing responses in language production. This impairment results in the inefficient avoidance of irrelevant information, inducing errors and slower responses during the production of spoken language.

Higher Impulsivity As a Distinctive Trait of Severe Cocaine Addiction among Individuals Treated for Cocaine or Alcohol Use Disorders

AIMS

Despite alcohol being the most often used addictive substance among addicted patients, use of other substances such as cocaine has increased over recent years, and the combination of both drugs aggravates health impairment and complicates clinical assessment. The aim of this study is to identify and characterize heterogeneous subgroups of cocaine- and alcohol-addicted patients with common characteristics based on substance use disorders, psychiatric comorbidity and impulsivity.

METHODS

A total of 214 subjects with cocaine and/or alcohol use disorders were recruited from outpatient treatment programs and clinically assessed. A latent class analysis was used to establish phenotypic categories according to diagnosis of cocaine and alcohol use disorders, mental disorders, and impulsivity scores. Relevant variables were examined in the latent classes (LCs) using correlation and analyses of variance and covariance.

RESULTS

Four LCs of addicted patients were identified: Class 1 (45.3%) formed by alcohol-dependent patients exhibiting lifetime mood disorder diagnosis and mild impulsivity; Class 2 (14%) formed mainly by lifetime cocaine use disorder patients with low probability of comorbid mental disorders and mild impulsivity; Class 3 (10.7%) formed by cocaine use disorder patients with elevated probability to course with lifetime anxiety, early and personality disorders, and greater impulsivity scores; and Class 4 (29.9%) formed mainly by patients with alcohol and cocaine use disorders, with elevated probability in early and personality disorders and elevated impulsivity. Furthermore, there were significant differences among classes in terms of Diagnostic and Statistical Manual of Mental Disorders-4th Edition-Text Revision criteria for abuse and dependence: Class 3 showed more criteria for cocaine use disorders than other classes, while Class 1 and Class 4 showed more criteria for alcohol use disorders.

CONCLUSION

Cocaine- and alcohol-addicted patients who were grouped according to diagnosis of substance use disorders, psychiatric comorbidity, and impulsivity show different clinical and sociodemographic variables. Whereas mood and anxiety disorders are more prevalent in alcohol-addicted patients, personality disorders are associated with cocaine use disorders and diagnosis of comorbid substance use disorders. Notably, increased impulsivity is a distinctive characteristic of patients with severe cocaine use disorder and comorbid personality disorders. Psychiatric disorders and impulsivity should be considered for improving the stratification of addicted patients with shared clinical and sociodemographic characteristics to select more appropriate treatments.

Drugs of Abuse

Drug abuse and its consequences remain a significant public health issue. An increasing number of individuals are present in the emergency room with life-threatening drug intoxication. It is imperative that emergency room physicians are cognizant of the signs, symptoms, and treatment to improve the chances of early recognition and treatment. As a result, the proportion of lives saved will increase significantly. In this article, we present some of the most prevalent life-threatening drugs that lead to emergency room admission. The signs, symptoms, and treatment modalities are discussed.

A Comprehensive View of the Neurotoxicity Mechanisms of Cocaine and Ethanol

Substance use disorder is an emerging problem concerning to human health, causing severe side effects, including neurotoxicity. The use of illegal drugs and the misuse of prescription or over-the-counter drugs are growing in this century, being one of the major public health problems. Ethanol and cocaine are one of the most frequently used drugs and, according to the National Institute on Drug Abuse, their concurrent consumption is one of the major causes for emergency hospital room visits. These molecules act in the brain through different mechanisms, altering the nervous system function. Researchers have focused the attention not just in the mechanism of action of these drugs, but also in the mechanism by which they damage the nervous tissue (neurotoxicity). Therefore, the goal of the present review is to provide a global perspective about the mechanisms of the neurotoxicity of cocaine and ethanol.

Chronic and recreational use of cocaine is associated with a vulnerability to semantic interference

RATIONALE

Language production requires that speakers effectively recruit inhibitory control to successfully produce speech. The use of cocaine is associated with impairments in cognitive control processes in the non-verbal domain, but the impact of chronic and recreational use of cocaine on these processes during language production remains undetermined.

OBJECTIVES

This study aims to observe the possible impairment of inhibitory control in language production among chronic and recreational cocaine polydrug users.

METHOD

Two experiments were carried out on chronic (experiment 1) and recreational (experiment 2) cocaine polydrug users performing a blocked-cycled naming task, yielding an index of semantic interference. Participants were matched for sex, age, and intelligence (Raven's Standard Progressive Matrices) with cocaine-free controls, and their performance was compared on the blocked-cycled naming task.

RESULTS

Chronic and recreational users showed significantly larger semantic interference effects than cocaine-free controls, thereby indicating a deficit in the ability to inhibit interfering information.

CONCLUSION

Evidence indicates a relationship between the consumption of cocaine, even at recreational levels, and the inhibitory processes that suppress the overactive lexical representations in the semantic context. This deficit may be critical in adapting and responding to many real-life situations where an efficient self-monitoring system is necessary for the prevention of errors.

Sex-specific dissociations in autonomic and HPA responses to stress and cues in alcohol-dependent patients with cocaine abuse

AIMS

Chronic alcohol and drug dependence leads to neuroadaptations in hypothalamic-pituitary-adrenal (HPA) and sympathetic adrenal medullary (SAM) stress systems, which impact response sensitivity to stress and alcohol cue and facilitates risk of relapse. To date, gender variations in these systems have not been fully assessed in abstinent alcohol-dependent individuals who also met criteria for cocaine abuse.

METHODS

Forty-two (21 M/21 F) early abstinent treatment-seeking substance-abusing (SA) men and women and 42 (21 M/21 F) healthy control (HC) volunteers were exposed to three 5-min guided imagery conditions (stress, alcohol/drug cue, neutral relaxing), presented randomly, one per day across three consecutive days. Alcohol craving and anxiety ratings were obtained as well as measures of heart rate (HR), blood pressure, plasma ACTH, cortisol, norepinephrine (NE) and epinephrine (EPI).

RESULTS

SA males showed increased ACTH and EPI basal tone compared with HC males and SA females. However, they demonstrated no increase in ACTH and cortisol levels following stress and alcohol cue imagery exposure compared to the neutral condition. SA females demonstrated a typically increased stress response in both measures. In addition, SA males showed no increase in cardiovascular response to either stress or cue, and no increase in catecholamine response to cue compared with their response to neutral imagery. Again, this dampening was not observed in HC males who produced significantly higher levels of cue-related HR and EPI, and significantly higher stress-related DBP. In contrast, SA females showed an enhanced ACTH and cortisol response to stress and cue compared with neutral imagery and this was not observed in the HC females. They also demonstrated a reduced increase in NE and EPI compared with both SA males and HC females as well as reduced HR compared with HC females.

CONCLUSIONS

While SA males showed a generalized suppression of HPA, SAM system and cardiovascular markers following both stress and cue, SA women demonstrated a selective sympatho-adrenal suppression to stress only and an enhanced HPA response to both stress and cue. These gender variations are discussed in terms of their potential impact on relapse vulnerability and treatment outcome.

Cellular and molecular mechanisms involved in the neurotoxicity of opioid and psychostimulant drugs

Substance abuse and addiction are the most costly of all the neuropsychiatric disorders. In the last decades, much progress has been achieved in understanding the effects of the drugs of abuse in the brain. However, efficient treatments that prevent relapse have not been developed. Drug addiction is now considered a brain disease, because the abuse of drugs affects several brain functions. Neurological impairments observed in drug addicts may reflect drug-induced neuronal dysfunction and neurotoxicity. The drugs of abuse directly or indirectly affect neurotransmitter systems, particularly dopaminergic and glutamatergic neurons. This review explores the literature reporting cellular and molecular alterations reflecting the cytotoxicity induced by amphetamines, cocaine and opiates in neuronal systems. The neurotoxic effects of drugs of abuse are often associated with oxidative stress, mitochondrial dysfunction, apoptosis and inhibition of neurogenesis, among other mechanisms. Understanding the mechanisms that underlie brain dysfunction observed in drug-addicted individuals may contribute to improve the treatment of drug addiction, which may have social and economic consequences.

Influence of ethanol and gender on methylphenidate pharmacokinetics and pharmacodynamics

This study explores the hypotheses that: (1) ethanol will interact with dl-Methylphenidate (MPH) to enantioselectively elevate plasma d-MPH, and primarily yield l-ethylphenidate as a transesterification metabolite; (2) women will exhibit lower relative bioavailability of MPH than men; and (3) sex-dependent differences in subjective effects will exist. dl-MPH HCl (0.3 mg/kg) was administered orally 30 min before ethanol, 30 min after ethanol (0.6 gm/kg), or without ethanol, in a randomized, normal subject three-way crossover study of 10 men and 10 women. Pharmacokinetic parameters were compared. Subjective effects were recorded using visual analog scales. One subject was a novel poor MPH metabolizer whose data were analyzed separately. Ethanol after or before MPH significantly (P<0.0001) elevated the geometric mean for the maximum d-MPH plasma concentration (C(max) (+/-SD)) from 15.3 (3.37) ng/ml to 21.5 (6.81) and 21.4 (4.86), respectively, and raised the corresponding geometric mean for the area under the concentration-time curve values from 82.9 (21.7) ng ml/h to 105.2 (23.5) and 102.9 (19.2). l-MPH was present in plasma only at 1-3% of the concentration of d-MPH, except in the poor metabolizer where l-MPH exceeded that of d-MPH. The metabolite l-ethylphenidate frequently exceeded 1 ng/ml in plasma, whereas d-ethylphenidate was detected only in low pg/ml concentrations. Women reported a significantly greater stimulant effect than men when questioned "Do you feel any drug effect?" (P<0.05), in spite of lower mean plasma d-MPH area under the response-time curves in women. Ethanol elevates plasma d-MPH C(max) and area under the concentration-time curve by approximately 40% and 25%, respectively. If the poor metabolizer of MPH proves to be a distinct phenotype, determining the genetic mechanism may be of value for individualizing drug therapy. The more pronounced stimulant effects experienced by women have sex-based abuse liability implications.

Cocaethylene affects human microvascular endothelial cell p38 mitogen-activated protein kinase activation and nuclear factor-kappaB DNA-binding activity

BACKGROUND

Cocaethylene (CE) is known to increase the permeability of human microvascular endothelial cell monolayers. The molecular mechanism underlying this increase may involve calcium-modulated signaling pathways such as the p38 mitogen-activated protein kinase (p38 MAPK) and the nuclear factor-kappaB (NF-kappaB) family of transcription factors. The hypothesis of this study was that CE-mediated endothelial permeability change may be mediated by the p38 MAPK and consequently NF-kappaB dimers.

METHODS

We used sandwich ELISA to detect phosphorylated p38 MAPK in the cell line human microvascular endothelial cell 1 (HMEC-1) after treatment with 1 mmol/L CE. We used electrophoretic mobility shift assay to detect changes in NF-kappaB dimers present in HMEC-1 and their DNA-binding activity after treatment with CE. Lipopolysaccharide (LPS) from Salmonella typhosa was used as a positive control for all experiments.

RESULTS

Treatment with CE and LPS had similar effects on HMEC-1 p38 MAPK phosphorylation and NF-kappaB DNA-binding activity. Both treatments increased the phosphorylation of p38 MAPK, consistent with activation of proinflammatory cell signaling. Treatment of HMEC-1 with CE decreased DNA binding of both the RelA/p50 and p50/p50 dimers of the NF-kappaB transcription factor family, whereas treatment with LPS decreased and then increased the DNA binding of these dimers.

CONCLUSION

In addition to increasing HMEC-1 monolayer permeability, CE also alters transcription factor and kinase activity related to inflammation. Thus, CE causes endothelial activation that can elicit a prolonged and organized cellular response, rather than being directly toxic to endothelial cells.

Sensitivity and specificity of the Cozart microplate EIA cocaine oral fluid at proposed screening and confirmation cutoffs

BACKGROUND

Oral fluid is currently being evaluated as an alternative matrix for monitoring illicit drugs in federally mandated workplace drug testing, for addiction treatment programs, and for driving under the influence testing. The sensitivity, specificity, and efficiency of the Cozart Microplate EIA Cocaine Oral Fluid Kit (COC ELISA) were determined by comparison with gas chromatography-mass spectrometry (GC/MS) results at screening and confirmation cutoffs proposed in the US and UK.

METHOD

Oral fluid was collected by expectoration after citric acid candy stimulation or with Salivette neutral cotton swabs or Salivette citric acid-treated cotton swabs before and after cocaine (COC) administration. Specimens (n = 1468) were analyzed with the COC ELISA for screening and with solid-phase extraction followed by GC/MS for confirmation. Three screening cutoffs (10, 20, and 30 microg/L) and four GC/MS cutoffs (2.5, 8, 10, and 15 microg/L COC, benzoylecgonine, and/or ecgonine methyl ester) were evaluated. GC/MS limit of quantification was 2.5 micro g/L for all analytes.

RESULTS

COC ELISA interassay imprecision (CV; n = 19) was 16% at 16.7 microg/L and 12% at 81.8 microg/L. With the 2.5, 8, 10, and 15 microg/L GC/MS cutoffs, 59.0%, 54.7%, 52.7%, and 48.7% of the oral fluid specimens were positive, respectively. Sensitivity, specificity, and efficiency were 92.2%, 84.7%, and 88.8%, respectively, for the suggested Substance Abuse and Mental Health Services Administration (SAMHSA) cutoffs and 90.2%, 89.2%, and 89.7% for cutoffs currently used in the UK.

CONCLUSIONS

COC ELISA had suitable sensitivity, specificity, and efficiency for identifying COC exposure at both the proposed SAMHSA and UK cutoffs. Sensitivity, specificity, and efficiency were >84% for both cutoffs, but 92 additional true-positive samples were identified with the SAMHSA cutoffs.

Cocaethylene's effects on coronary artery blood flow and cardiac function in a canine model

OBJECTIVES

Cocaethylene is a toxic metabolite of cocaine formed in the presence of ethanol. Though cocaine causes coronary vasoconstriction, cocaethylene's effects on coronaryflow are unknown. The aim of our study was to describe cocaethylene 's effects on coronary flow and cardiac function.

METHODS

Sixteen alpha-chloralose anesthetized dogs were monitored with Swan-Ganz, arterial and venous catheters, and an electrocardiogram. Dopplerflow probes were placed on the circumflex and left anterior descending coronary arteries. Dogs were allotted 15 mg/kg (n = 10) or 30mg/kg (n = 6) of cocaethylene given as a continuous intravenous infusion. Measurements were made at fixed time intervals during the 60-minute cocaethylene infusion and 2-hour observation period.

RESULTS

The cocaethylene concentrations were maximal at the end of the infusion and cocaethylene was rapidly metabolized to benzoylecognine. One low-dose animal died of ventricular fibrillation. Five high-dose dogs experienced ventricular arrhythmias or pulseless electrical activity (PEA), and three died. In the low-dose group, cocaethylene caused a 38% increase in mean arterial pressure relative to baseline, and increased systemic vascular resistance. In the high-dose group, at maximal cocaethylene concentrations, stroke volume decreased by 42% (p < 0.0002), and circumflex blood flow decreased by 30% (p = 0.03) relative to baseline, when arrhythmias occurred. The PR, QRS, and QTc intervals increased by 48, 209, and 29%, respectively (p < 0.001). As cocaethylene levels declined, circumflex blood flow increased by 77% (p = 0.05) and mean arterial pressure increased 49% (p < 0.01), also relative to baseline.

CONCLUSIONS

Cocaethylene caused hypertension and increased systemic vascular resistance. At high concentrations, it decreased myocardial function, slowed cardiac conduction, and was arrhythmogenic. The cocaethylene's toxicity does not appear to be mediated by effects on coronary blood flow.

Effects of concurrent use of alcohol and cocaine

The combination of alcohol and cocaine is popular among drug users, perhaps because of more intense feelings of 'high' beyond that perceived with either drug alone, less intense feelings of alcohol-induced inebriation and tempering of discomfort when coming down from a cocaine 'high'. A review is presented of the medical literature on psychological and somatic effects and consequences of combined use of alcohol and cocaine in man. The search was carried out with Medline, the Science Citation Index/Web of Science and Toxline. Exclusion and inclusion criteria for this search are identified. There is generally no evidence that the combination of the two drugs does more than enhance additively the already strong tendency of each drug to induce a variety of physical and psychological disorders. A few exceptions must be noted. Cocaine consistently antagonizes the learning deficits, psychomotor performance deficits and driving deficits induced by alcohol. The combination of alcohol and cocaine tends to have greater-than-additive effects on heart rate, concomitant with up to 30% increased blood cocaine levels. Both prospective and retrospective data further reveal that co-use leads to the formation of cocaethylene, which may potentiate the cardiotoxic effects of cocaine or alcohol alone. More importantly, retrospective data suggest that the combination can potentiate the tendency towards violent thoughts and threats, which may lead to an increase of violent behaviours.

Acute and chronic alcohol-cocaine interactions in rats

The widespread combined use of alcohol and cocaine across the United States underscores the importance of understanding how the actions of those two agents interact upon important physiological regulatory processes. In an experiment exploring acute ethanol-cocaine interactions, 16 rats were given 2.0 g/kg (IP) doses of ethanol at time zero. Two hours later, half of the rats were given cocaine (20 mg/kg, IP), while the other half were given injections of saline. The group given cocaine displayed a prolongation of the hypothermia condition induced by ethanol injection. In a chronic experiment, three groups of rats (n = 6-8) were exposed for an 11-day period to daily IP injections of 10 mg/kg cocaine, 20 mg/kg of cocaine, or saline. On day 12 these groups did not differ in their response to loss of the righting reflex induced by a 3.0 g/kg dose of ethanol. However, recovery from ethanol hypothermia was more rapid in the rats exposed to chronic cocaine. In summary, these initial studies provide evidence for exacerbation of the acute hypothermic effects of ethanol when a cocaine challenge is given 2 h after ethanol. In contrast, ethanol hypothermia was observed to be reduced when tested on day 12 after an 11-day chronic regimen of cocaine. Other dosage regimens and response measures need to be tested to understand the full scope of acute and chronic cocaine-ethanol interactions and the possible health consequences.

Cocaine metabolism and urinary excretion after different routes of administration

Cocaine abusers frequently self-administer cocaine by different routes of administration. A controlled-dosing study was performed to assess the effect of different routes of administration on the excretion profile of cocaine and metabolites in urine. Single bioequivalent doses of cocaine were administered by the intravenous, intranasal, and smoked routes to six human subjects. Urine specimens were collected for 3 days after drug administration and were analyzed for cocaine, metabolites, and anhydroecgonine methyl ester, the thermal degradation product of cocaine, by gas chromatography-mass spectrometry. Cocaine was rapidly absorbed, metabolized, and excreted in urine. Peak cocaine concentrations were generally present in the first specimen collected; thereafter, concentrations declined quickly and were usually below the limit of detection (approximately 1 ng/ml) within 24 hours. The metabolite benzoylecgonine was present in the highest concentration and represented approximately 39%, 30%, and 16%, of the administered dose by the intravenous, intranasal, and smoked routes, respectively. Combined amounts of ecgonine methyl ester and six minor metabolites (norcocaine, benzoylnorecgonine, m-hydroxycocaine, p-hydroxycocaine, m-hydroxybenzoylecgonine, and p-hydroxybenzoylecgonine) accounted for approximately 18%, 15%, and 8% of the administered dose by the intravenous, intranasal, and smoked routes, respectively. Anhydroecgonine methyl ester was present in trace amounts (0.02% dose) in specimens collected after smoked cocaine administration. Because many of these metabolites exhibit pharmacologic activity, their presence in urine may indicate that they play complex biologic roles in the overall activity of cocaine.

Cocaine and alcohol synergism in taste aversion learning

Female Long-Evans rats were given 20-min access to saccharin followed by injections of alcohol and cocaine, alone and in combination. Although there was no significant interaction between alcohol and cocaine when cocaine was given intraperitoneally (IP), aversions induced by the drug combination when cocaine was administered subcutaneously (SC) were significantly greater than those induced by either drug alone. Further, the aversions induced by the combination were significantly greater than the summed effects of the individual drugs administered alone, indicating a synergistic interaction between cocaine and alcohol. It was suggested that this synergism might result from a summation of the effects of alcohol, cocaine, and cocaethylene, a unique and toxic metabolite of cocaine produced when alcohol is coadministered. To assess the role of cocaethylene in the present design, additional taste aversion assessments were performed in which saccharin was paired with either IP or SC injections of cocaethylene. Although cocaethylene was found to induce aversions, the summed changes in consumption from baseline produced by cocaine, alcohol, and cocaethylene were significantly less than the changes produced by cocaine and alcohol in combination. These results indicate that the synergistic interaction between cocaine and alcohol in the present design cannot be attributed solely to summation of the effects of the individual drugs and the metabolite cocaethylene. Additional mechanisms by which cocaethylene might contribute to the synergistic interaction between cocaine and alcohol, as well as the role pharmacokinetic interactions between cocaine and alcohol might have in the interaction, were discussed.