Cocaine and adrenaline paste: a fatal combination?

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.

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.

Assessing the safety and efficacy of drugs used in preparing the nose for diagnostic and therapeutic procedures: a systematic review

BACKGROUND

Local anaesthetics and vasoconstrictors are essential for pain control and to aid intra-operative haemostasis in nasal procedures. They also improve access, and reduce discomfort when performing nasal endoscopy. There are no clear guidelines on preparing the nose despite evermore diagnostic and therapeutic procedures utilising the nose as a point of access.

OBJECTIVE OF REVIEW

This review aims to identify nasal preparations used in diagnostic and therapeutic nasal procedures and to examine their safety and efficacy.

TYPE OF REVIEW

Systematic review.

SEARCH STRATEGY

A search was carried out using PubMed, MEDLINE, Ovid EMBASE, the Cochrane library and references from the included articles.

EVALUATION METHOD

The inclusion criteria included: full-text English language articles with regard to nasal preparation for surgery. Case reports, systematic reviews, meta-analysis, double-blind placebo controlled randomised trials (RCTs) and case series were included.

RESULTS

A total of 53 articles were retrieved: 13 articles on nasal preparation for operative procedures, six on functional endoscopic sinus surgery and 22 on nasendoscopy as well as six case reports. Cocaine was the most widely used topical preparation for operative procedures but was associated with more side-effects; thus, topical tetracaine and levobupivacaine infiltration are alternatives with equivalent efficacy but reduced adverse effects. All articles reviewed for functional endoscopic sinus surgery used a mixture containing lidocaine, adrenaline or both. Flexible nasendoscopy causes minimal patient discomfort and preparation is only recommended in selected patients, in contrast to rigid nasendoscopy which requires preparation.

CONCLUSION

For operative procedures, such as septorhinoplasty, a single agent tetracaine or levobupivicaine provides an improved surgical field. In functional endoscopic sinus surgery, lidocaine-adrenaline preparations have resulted in significantly better surgical and patient outcomes. There is little evidence to support the routine use of pre-procedural nasal preparation for flexible nasendoscopy. Those undergoing rigid endoscopy conversely always require the use of a vasoconstrictor and local anaesthetic. Pre-procedure assessment of patients is recommended, with agents being reserved for those with low pain thresholds, high anxiety and small nasal apertures presenting resistance to the insertion of the endoscope.

Electrocardiographic findings associated with cocaine use in humans: a systematic review

Cocaine remains highly prevalent and accessible in the general population, continues to represent one of the most commonly reported substances in drug-related presentations to emergency departments, and is frequently implicated in drug-related deaths. Fatal cardiac arrhythmias are often suspected in the latter cases. In spite of this, its complex effects on the human cardiac conduction system remain poorly elucidated. In this article we sought to systematically review the medical literature to identify the electrocardiographic findings that have been linked to cocaine use in humans in an effort to highlight what physicians can expect to encounter when managing patients using the drug. The evidence is discussed, common findings are emphasized and clinical recommendations are proposed.

Does epinephrine infiltration in septoplasty make any difference? A double blind randomised controlled trial

Infiltration of lignocaine with epinephrine is used with cocaine in septoplasty, in attempt to improve haemostasis and thereby improve the surgical field. This practice is widespread despite the lack of evidence to support its efficacy in the literature. Thirty patients undergoing septoplasty were randomised into two groups -- one in whom infiltration was performed with lignocaine (2%) with adrenaline (1:80,000) and a control group who received lignocaine (2%). Both groups of patients received intranasal application of cocaine paste prior to surgery. The surgeon and anaesthetist were blinded to the contents of the infiltration. The operative field was rated by the surgeon, and the blood loss calculated. No significant difference was demonstrated in blood loss or surgical field between the groups. However there was significant rise in systolic blood pressure in patients who received epinephrine. The use of epinephrine with cocaine paste does not improve haemostasis or surgical field. As the use of epinephrine is associated with cardiac arrhythmias, the authors suggest that combined use of cocaine paste and epinephrine infiltration should be avoided in septal surgery.

Does cocaine still have a role in nasal surgery?

Endonasal surgery is already very common and its importance is increasing. Successful anaesthesia in endonasal sinus surgery is of critical importance for the success of the procedure and many surgeons prefer to use cocaine for this purpose. However, there is a great body of evidence that suggests that use of cocaine, even in experienced hands, can cause rapid, unexpected and severe toxic reactions. Therefore, its use in endonasal surgery can no longer be recommended, especially since better tolerated alternatives are available for topical and infiltration anaesthesia. These alternatives include lidocaine (lignocaine) and tetracaine (pantocaine) in combination with epinephrine (adrenaline), naphazoline or oxymetazoline.

The recreational drug user in the intensive care unit: a review

This paper describes the mode of action of a set of recreational drugs that may cause patients problems that are severe enough to warrant admission to an intensive care unit. The mechanism of harm will be examined as well as some of the strategies used to deal with these problems. A general view of the chosen group will be outlined, followed by a breakdown of the drugs into specific categories, with review of the harmful effects of individual drugs. It is the intention of the authors to review depressant drugs at a later stage.

ABC of urology. Introduction to urology

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