Propoxyphene-induced wide QRS complex dysrhythmia responsive to sodium bicarbonate--a case report

Overdose of Dologesic with a Fatal Outcome: A Case Report

Dologesic is a commonly prescribed analgesic in accident and emergency department. Yet report of overdose with this drug is not common. We report a case in which the patient developed cardiac arrest within an hour of ingestion. Dextropropoxyphene, a component of the drug Dologesic, used to be a common cause of fatalities after drug overdose in the seventies. It is highly toxic in overdose and therefore caution should be exercised when prescribing this drug.

A Literature Review of the Use of Sodium Bicarbonate for the Treatment of QRS Widening

Sodium bicarbonate is a well-known antidote for tricyclic antidepressant (TCA) poisoning. It has been used for over half a century to treat toxin-induced sodium channel blockade as evidenced by QRS widening on the electrocardiogram (ECG). The purpose of this review is to describe the literature regarding electrophysiological mechanisms and clinical use of this antidote after poisoning by tricyclic antidepressants and other agents. This article will also address the literature supporting an increased serum sodium concentration, alkalemia, or the combination of both as the responsible mechanism(s) for sodium bicarbonate's antidotal properties. While sodium bicarbonate has been used as a treatment for cardiac sodium channel blockade for multiple other agents including citalopram, cocaine, flecainide, diphenhydramine, propoxyphene, and lamotrigine, it has uncertain efficacy with bupropion, propranolol, and taxine-containing plants.

Neurotoxic emergencies

This article is intended for clinicians treating neurotoxic emergencies. Presented are causative agents of neurotoxic emergencies, many of which are easily mistaken for acute psychiatric disorders. Understanding the wide variety of agents responsible for neurotoxic emergencies and the neurotransmitter interactions involved will help the psychiatrist identify and treat this challenging population.

Toxidromes

The critical care physician is often called to care for poisoned patients. This article reviews the general approach to the poisoned patient, specifically focusing on the utility of the toxidrome. A toxidrome is a constellation of findings, either from the physical examination or from ancillary testing, which may result from any poison. There are numerous toxidromes defined in the medical literature. This article focuses on the more common toxidromes described in clinical toxicology. Although these toxidromes can aid the clinician in narrowing the differential diagnosis, care must be exercised to realize the exceptions and limitations associated with each.

Seizures as a cause of altered mental status

The differential diagnosis and empiric management of altered mental status and seizures often overlap. Altered mental status may accompany seizures or simply be the manifestation of a postictal state. This article provides an overview of the numerous causes of altered mental status and seizures: metabolic, toxic, malignant, infectious, and endocrine causes. The article focuses on those agents that should prompt the emergency physician to initiate unique therapy to abate the seizure and correct the underlying cause.

Drugs and pharmaceuticals: management of intoxication and antidotes

The treatment of patients poisoned with drugs and pharmaceuticals can be quite challenging. Diverse exposure circumstances, varied clinical presentations, unique patient-specific factors, and inconsistent diagnostic and therapeutic infrastructure support, coupled with relatively few definitive antidotes, may complicate evaluation and management. The historical approach to poisoned patients (patient arousal, toxin elimination, and toxin identification) has given way to rigorous attention to the fundamental aspects of basic life support--airway management, oxygenation and ventilation, circulatory competence, thermoregulation, and substrate availability. Selected patients may benefit from methods to alter toxin pharmacokinetics to minimize systemic, target organ, or tissue compartment exposure (either by decreasing absorption or increasing elimination). These may include syrup of ipecac, orogastric lavage, activated single- or multi-dose charcoal, whole bowel irrigation, endoscopy and surgery, urinary alkalinization, saline diuresis, or extracorporeal methods (hemodialysis, charcoal hemoperfusion, continuous venovenous hemofiltration, and exchange transfusion). Pharmaceutical adjuncts and antidotes may be useful in toxicant-induced hyperthermias. In the context of analgesic, anti-inflammatory, anticholinergic, anticonvulsant, antihyperglycemic, antimicrobial, antineoplastic, cardiovascular, opioid, or sedative-hypnotic agents overdose, N-acetylcysteine, physostigmine, L-carnitine, dextrose, octreotide, pyridoxine, dexrazoxane, leucovorin, glucarpidase, atropine, calcium, digoxin-specific antibody fragments, glucagon, high-dose insulin euglycemia therapy, lipid emulsion, magnesium, sodium bicarbonate, naloxone, and flumazenil are specifically reviewed. In summary, patients generally benefit from aggressive support of vital functions, careful history and physical examination, specific laboratory analyses, a thoughtful consideration of the risks and benefits of decontamination and enhanced elimination, and the use of specific antidotes where warranted. Data supporting antidotes effectiveness vary considerably. Clinicians are encouraged to utilize consultation with regional poison centers or those with toxicology training to assist with diagnosis, management, and administration of antidotes, particularly in unfamiliar cases.

Critical care toxicology

Emergency physicians are regularly called on to care for critically poisoned patients. This article reviews the general approach and management of the critically poisoned patient. Specific clinical characteristics are identified that may clue the clinician into a specific toxin class as a diagnosis. Appropriate testing in the poisoned patient is reviewed. Complications of poisoning that may bring a rapid demise of the critically ill poisoned patient are highlighted and the management of those complications is discussed.

Propoxyphene (dextropropoxyphene): a critical review of a weak opioid analgesic that should remain in antiquity

Propoxyphene (dextropropoxyphene) is a synthetic weak opioid introduced into the United States in 1957. It is most frequently prescribed in combination with acetaminophen and/or aspirin. After its ubiquitous introductory phase, it was soon discovered that this drug's iatrogenic events (cardiotoxicity, seizures, etc.) far outweighed any perceived therapeutic benefit. Propoxyphene analgesia was equated with that of merely acetaminophen or aspirin independently. The propoxyphenes euphorigenic component has created a problem in its prescribing. Use of this agent in the elderly should be avoided because of its complex pharmacokinetics and pharmacodynamics. The pharmacokinetics, pharmacodynamics, and pharmacology of this drug are discussed thoroughly in this article, including its arrhythmogenicity. Additional noncardiovascular pharmacotherapies that produce QTc prolongation or arrhythmogenicity are described. A list of the cytochrome P450 2D6 pharmacotherapies that will interact with propoxyphene is provided in the article. The use of this agent is highly discouraged. The rationale for this is discussed fully within this article. The toxicity of this drug is partially related to nor-propoxyphene a non-opioid cardiotoxic metabolite. The mere warnings of fatalities within the package insert should alert any cautious prescriber on the dangers of this agent and dampen its prescribing potential.

Chemically Induced Seizures

Drug- and toxin-associated seizures (DTS) may result from exposure to a wide variety of agents. Most DTS can be managed with supportive care. First-line anticonvulsant therapy should include benzodiazepines, unless agents require a specific antidote. Phenytoin is generally not expected to be useful for DTS and in some instances may be harmful. In this article the authors discuss the pathophysiology of DTS, the potential differential diagnosis, and the clinical presentation. They also review selected agents that cause DTS and provide an overview of how the clinician should approach the management of patients who have DTS.

ECG Manifestations: The Poisoned Patient

Despite that drugs have widely varying indications for therapeutic use, many unrelated drugs share a common cardiac pharmacologic effect if taken in overdose. The purpose of this article is to group together agents that cause similar electrocardiographic effects,review their pharmacologic actions, and discuss the electrocardiographic findings reported in the medical literature.

Utilizing diagnostic investigations in the poisoned patient

Numerous diagnostic tests may be useful to clinicians caring for poisoned patients. Clinicians should not order a broad range of tests indiscriminately,but rather thoughtfully consider appropriate tests. The results'of the tests should be reviewed in the context of the clinical scenario.

Drug- and toxin-associated seizures

Drug- and toxin-associated seizures may result from exposure to a wide variety of agents. Obtaining a comprehensive history behind the exposure is generally more helpful than diagnostic testing. Most DTS may be managed with supportive care, including benzodiazepines, except in the case of agents that require a specific intervention or antidote.

Acute poisoning: understanding 90% of cases in a nutshell

The acutely poisoned patient remains a common problem facing doctors working in acute medicine in the United Kingdom and worldwide. This review examines the initial management of the acutely poisoned patient. Aspects of general management are reviewed including immediate interventions, investigations, gastrointestinal decontamination techniques, use of antidotes, methods to increase poison elimination, and psychological assessment. More common and serious poisonings caused by paracetamol, salicylates, opioids, tricyclic antidepressants, selective serotonin reuptake inhibitors, benzodiazepines, non-steroidal anti-inflammatory drugs, and cocaine are discussed in detail. Specific aspects of common paediatric poisonings are reviewed.

Emergency department observation for toxicologic exposures

Most toxicologic exposures resolve within 24 hours, yet catastrophic outcomes may occur if patients are directly discharged from the emergency department (ED). These cases are, perhaps, the ideal candidates for observation unit (OU) management. This article reviews the criteria for admission and discharge as well as clinical management strategies in the OU for the most common toxicologic exposures. Special attention is given to the multidisciplinary interactions among the ED physician, the medical toxicologist, the physiatrist, and the specialty laboratory.

Pharmacokinetics of opioids in liver disease

The liver is the major site of biotransformation for most opioids. Thus, the disposition of these drugs may be affected in patients with liver insufficiency. The major metabolic pathway for most opioids is oxidation. The exceptions are morphine and buprenorphine, which primarily undergo glucuronidation, and remifentanil, which is cleared by ester hydrolysis. Oxidation of opioids is reduced in patients with hepatic cirrhosis, resulting in decreased drug clearance [for pethidine (meperidine), dextropropoxyphene, pentazocine, tramadol and alfentanil] and/or increased oral bioavailability caused by a reduced first-pass metabolism (for pethidine, dextropropoxyphene, pentazocine and dihydrocodeine). Although glucuronidation is thought to be less affected in liver cirrhosis, and clearance of morphine was found to be decreased and oral bioavailability increased. The consequence of reduced drug metabolism is the risk of accumulation in the body, especially with repeated administration. Lower doses or longer administration intervals should be used to remedy this risk. Special risks are known for pethidine, with the potential for the accumulation of norpethidine, a metabolite that can cause seizures, and for dextropropoxyphene, for which several cases of hepatotoxicity have been reported. On the other hand, the analgesic activity of codeine and tilidine depends on transformation into the active metabolites, morphine and nortilidine, respectively. If metabolism is decreased in patients with chronic liver disease, the analgesic action of these drugs may be compromised. Finally, the disposition of a few opioids, such as fentanyl, sufentanil and remifentanil, appears to be unaffected in liver disease.

Arrhythmias associated with drug toxicity

Cardiac arrhythmias may result from poisoning by a variety of agents. Although some cardiac disturbances are of limited concern, others occur because of the specific cardiac properties of the ingested drugs, and require specific antidotes. Clinicians must understand the resultant pathophysiology so that therapy is appropriate. This article focuses on drugs that cause ventricular arrhythmias and bradyarrhythmias.

Poisoning by sodium channel blocking agents

Poisoning by drugs that block voltage-gated sodium channels produces intraventricular conduction defects, myocardial depression, bradycardia, and ventricular arrhythmias. Human and animal reports suggest that hypertonic sodium bicarbonate may be effective therapy for numerous agents possessing sodium channel blocking properties, including cocaine, quinidine, procainamide, flecainide, mexiletine, bupivacaine, and others.

Cocaine-induced wide complex dysrhythmia

Cocaine is a local anesthetic with the potential to induce dysrhythmia due to direct myocardial sodium channel antagonism similar to class I antidysrhythmic drugs. The hallmark of myocardial sodium channel poisoning is wide complex dysrhythmia, and the current accepted treatment is intravenous bicarbonate. Wide complex dysrhythmio due to cocaine in the absence of myocardial infarction is rare, and optimum management is undefined. We report three cases of acute cocaine intoxicating during which patients developed wide complex dysrhythmia consistent with sodium channel poisoning. In one case, wide complex tachycardia resolved without direct treatment. In the other cases, wide complex dysrhythmia resolved following intravenous bicarbonate therapy directed at reversing sodium channel blockade.