Tylenol Extended Relief overdose

Performance of the paracetamol-aminotransferase multiplication product in risk stratification after paracetamol (acetaminophen) poisoning: a systematic review and meta-analysis

BACKGROUND

Risk stratification in paracetamol (acetaminophen) poisoning is crucial because hepatotoxicity is common and can be mitigated with treatment. However, current risk stratification tools have limitations.

AIMS

We evaluated the diagnostic performance of the paracetamol concentration × aminotransferase multiplication product, for predicting hepatotoxicity after paracetamol overdose.

METHODS

Medline, Cochrane Library and Embase were searched for eligible papers. We used random effects models to obtain pooled estimates of the likelihood ratios and diagnostic odds ratios, from which sensitivity and specificity were computed. We assessed two commonly used cut-off values of paracetamol × aminotransferase, 1500 mg/L × IU/L and 10,000 mg/L × IU/L. Using the confusion matrices of these two cut-offs, area under the summary receiver operator characteristic curve and optimal cut-off values in different clinical scenarios were established.

RESULTS

Six studies comprising 5036 participants were included. In 4051 patients, using the cut-off of 1500 mg/L × IU/L, a diagnostic odds ratio of 31.90 (95%CI: 9.52-106.90), sensitivity of 0.98 (95%CI: 0.94-1.00) and specificity of 0.66 (95%CI: 0.49-0.89) were obtained. In 3983 patients, using the cut-off of 10,000 mg/L × IU/L, a diagnostic odds ratio of 99.34 (95%CI: 12.26-804.87), sensitivity of 0.65 (95%CI: 0.51-0.82) and specificity of 0.97 (95%CI: 0.95-1.00) were obtained. For staggered ingestions, the 1500 mg/L × IU/L cut-off yielded a diagnostic odds ratio of 69.53 (95%CI: 4.03-1199.75), sensitivity of 1.00 (95%CI: 0.87-1.00) and specificity of 0.74 (95%CI: 0.43-1.00). Next, using the 10,000 mg/L × IU/L cut-off in this scenario yielded a diagnostic odds ratio of 254.58 (95%CI: 11.12-5827.60), sensitivity of 0.79 (95%CI: 0.59-1.00) and specificity of 0.98 (95%CI: 0.94-1.00). The overall summary receiver operator characteristic curve was 0.91 (95%CI: 0.75-0.97), and the optimal cut-off value was 3840 mg/L × IU/L. The summary receiver operator characteristic curve in patients with staggered ingestions was 0.96 (95%CI: 0.85-0.99). The summary receiver operator characteristic curve in patients with staggered ingestions and whose paracetamol concentration was below the detectable limit of 10 mg/L at presentation was 0.97 (95%CI: 0.94-0.99).

CONCLUSION

In this first meta-analysis, paracetamol × aminotransferase demonstrates its use in prognosticating hepatotoxicity in patients with paracetamol poisoning. It complements the Rumack-Matthew nomogram as it has shown promise in addressing two key limitations of the nomogram: it is usable after more than 24 h between overdose and acetylcysteine treatment, and it is applicable in staggered ingestions.

Population pharmacokinetic analysis of acetaminophen overdose with immediate release, extended release and modified release formulations

OBJECTIVES

The introduction of delayed release formulations of acetaminophen (APAP) has created concern about the role of formulation in overdose. We examined the APAP overdose pharmacokinetic (PK) profiles to assess the role of dose, coingestants and formulation: immediate release (IR), extended release (ER), and modified release (MR) on APAP pharmacokinetic measures.

METHODS

We collected by-subject APAP PK data: subject description, timed blood APAP concentrations, dose, and coingestants. We sought both overdose and randomized controlled trials (RCTs) for supratherapeutic doses involving ER or MR formulations. Data analysis and simulation used the non-linear mixed-effects modeling program NONMEM-version 7.4.

RESULTS

The final dataset comprised 3,033 [APAP] from 356 subjects and 15 sources including 3 RCTs (179 subjects receiving IR, 122 ER, 65 MR). The final population PK (PopPK) model was a linear 2-compartment model with first-order (oral) absorption. Covariate relationships included: APAP absorption rate and bioavailability decreased with increased oral dose (p < 0.00005) for all 3 formulations (MR > ER > IR). Post hoc analyses showed opioid coingestant increased exposure (area under the curve, AUC) by factor of 1.6. Simulations of 100 g vs 10 g doses for IR, ER and MR showed overdose of the ER formulation exhibits slower absorption and lower C_max, overall exposure (AUC) is less than 80% of an equivalent dose of IR acetaminophen. The overall exposure for the MR formulation is less than 70% of an equivalent dose of IR.

CONCLUSIONS

Acetaminophen ER and MR formulations have slower absorption and decreased bioavailability leading to a lower C_max and later T_max than the IR formulation. These results have potential clinical implications because delayed absorption could confound use of the Rumack-Matthew nomogram by underestimating the severity of ingestion early in the course of treatment.

Acetaminophen Poisoning

Acetaminophen is a common medication taken in deliberate self-poisoning and unintentional overdose. It is the commonest cause of severe acute liver injury in Western countries. The optimal management of most acetaminophen poisonings is usually straightforward. Patients who present early should be offered activated charcoal and those at risk of acute liver injury should receive acetylcysteine. This approach ensures survival in most. The acetaminophen nomogram is used to assess the need for treatment in acute immediate-release overdoses with a known time of ingestion. However, scenarios that require different management pathways include modified-release, large/massive, and repeated supratherapeutic ingestions.

Point-of-Care Determination of Acetaminophen Levels with Multi-Hydrogen Bond Manipulated Single-Molecule Recognition (eMuHSiR)

This work aims to face the challenge of monitoring small molecule drugs accurately and rapidly for point-of-care (POC) diagnosis in current clinical settings. Overdose of acetaminophen (AP), a commonly used over the counter (OTC) analgesic drug, has been determined to be a major cause of acute liver failure in the US and the UK. However, there is no rapid and accurate detection method available for this drug in the emergency room. The present study examined an AP sensing strategy that relies on a previously unexplored strong interaction between AP and the arginine (Arg) molecule. It was found that as many as 4 hydrogen bonds can be formed between one Arg molecule and one AP molecule. By taking advantages of this structural selectivity and high tenability of hydrogen bonds, Arg, immobilized on a graphene surface via electrostatic interactions, was utilized to structurally capture AP. Interestingly, bonded AP still remained the perfect electrochemical activities. The extent of Arg-AP bonds was quantified using a newly designed electrochemical (EC) sensor. To verify the feasibility of this novel assay, based on multihydrogen bond manipulated single-molecule recognition (eMuHSiR), both pharmaceutical and serum sample were examined. In commercial tablet measurement, no significant difference was seen between the results of eMuHSiR and other standard methods. For measuring AP concentration in the mice blood, the substances in serum, such as sugars and fats, would not bring any interference to the eMuHSiR in a wide concentration range. This eMuHSiR method opens the way for future development of small molecule detection for the POC testing.

Management of Acute Hepatotoxicity Including Medical Agents and Liver Support Systems

Drug-induced liver injury (DILI) can be predictable or idiosyncratic and has an estimated incidence of approximately 20 cases per 100,000 persons per year. DILI is a common cause of acute liver failure in the United States. No accurate tests for diagnosing DILI exist, and its diagnosis is based on exclusion of other conditions. Managing DILI includes discontinuing the suspected causative agent and in selected cases administering an antidote. Liver support systems are used for long-term support or as a bridge to transplantation and are effective for improving encephalopathy, hyperbilirubinemia, and other liver-related conditions, but whether they improve survival remains uncertain.

A review of acetaminophen poisoning

Acetaminophen poisoning remains one of the more common drugs taken in overdose with potentially fatal consequences. Early recognition and prompt treatment with N-acetylcysteine can prevent hepatic injury. With acute overdose, the Rumack-Matthew nomogram is a useful tool to assess risk and guide management. Equally common to acute overdose is the repeated use of excessive amounts of acetaminophen. Simultaneous ingestion of several different acetaminophen-containing products may result in excessive dosage. These patients also benefit from N-acetylcysteine. Standard courses of N-acetylcysteine may need to be extended in patients with persistently elevated plasma concentrations of acetaminophen or with signs of hepatic injury.

Unexpected late rise in plasma acetaminophen concentrations with change in risk stratification in acute acetaminophen overdoses

BACKGROUND

The acetaminophen risk analysis nomogram is used to predict hepatotoxicity risk in acute acetaminophen overdose based on a single plasma acetaminophen concentration (PAC) measured between 4 and 24 h after ingestion. There are case reports of patients with acute overdoses of acetaminophen combination products in whom a toxic PAC occurred later after an initial non-toxic PAC at approximately 4 h.

OBJECTIVES

The objective was to describe patients who had an initial non-toxic PAC and a subsequent toxic PAC.

METHODS

A poison center's database was searched for records in which patients were administered N-acetylcysteine. Cases were included if they involved an acute overdose of an acetaminophen-containing product with at least 2 plottable PACs, the first of which was obtained at least 4 h after ingestion and was below the treatment line on the nomogram with a subsequent toxic PAC. Data were analyzed for doses, timed PACs, specific acetaminophen preparation, coingestants, activated charcoal administration, and clinical effects.

RESULTS

Twenty patients were included. Thirteen patients ingested combination products. All patients experienced vomiting, neurologic, or cardiovascular effects at presentation or before obtaining the second PAC. Two patients developed hepatotoxicity, one of which died from the complications of acetaminophen-induced hepatotoxicity.

CONCLUSION

The nomogram fails to predict toxicity based on a single PAC in a small subset of patients.

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.

Acetaminophen Overdose with Altered Acetaminophen Pharmacokinetics and Hepatotoxicity Associated with Premature Cessation of Intravenous N-Acetylcysteine Therapy

Objective

To report a case of erratic absorption, double peak serum concentrations, and hepatotoxicity following premature cessation of intravenous N-acetylcysteine (NAC) treatment in the setting of a massive acetaminophen overdose.

Case Summary:

A 78-year-old man reportedly ingested approximately 96 immediate-release acetaminophen 500-mg tablets (48 g) over a one-hour period in an apparent suicide attempt. The acetaminophen concentration at 2.25 hours was 264 μg/mL. Intravenous NAC was initiated 5 hours postingestion. At 6.25 hours postingestion, the acetaminophen concentration was 281 μg/mL. Following administration of intravenous NAC for 21 hours, therapy was discontinued despite a residual acetaminophen concentration of 116 μg/mL. The patient experienced hepatotoxicity, coagulopathy, and renal injury. Pharmacokinetic analysis revealed significantly prolonged acetaminophen absorption and a second peak acetaminophen concentration of 228 μg/mL approximately 48 hours post ingestion. Direct in-hospital monitoring of the patient made a second ingestion unlikely.

Discussion:

Acetaminophen overdose is usually effectively managed with NAC. Patients with massive ingestions may have altered absorption kinetics due to acetaminophen's solubility being exceeded, physiologically or chemically altered gastrointestinal emptying or motility, or other factors. These patients may benefit from gastrointestinal decontamination and prolonged NAC therapy.

Conclusions:

In patients with massive acetaminophen ingestion, erratic absorption may occur, and toxic serum concentrations may persist beyond a standard 21–hour course of intravenous NAC therapy. Acetaminophen concentrations and aminotransferase levels should be evaluated at the completion of the intravenous NAC infusion to ensure complete elimination of acetaminophen and absence of hepatotoxicity and to exclude the need lor prolonged treatment.

Toxicology in the critical care unit

Toxicologic conditions are encountered in critically ill patients due to intentional or unintentional misuse of or exposure to therapeutic or illicit drugs. Additionally, toxicities related to medical interventions may develop in hospitalized patients. This review focuses on recent developments in the field of critical care toxicology. Early interventions to decrease absorption or enhance elimination of toxins have limited value. Specific interventions to manage toxicities due to analgesics, sedative-hypnotics, antidepressants, antipsychotics, cardiovascular agents, alcohols, carbon monoxide, and cholinergic agents are reviewed. Hospital-acquired toxicities due to methemoglobinemia, propylene glycol, and propofol should be recognized and treated. The clinician is continually required to incorporate clinical judgment along with available scientific data and clinical evidence to determine the best therapy for toxicologic conditions.

Clinical policy: critical issues in the management of patients presenting to the emergency department with acetaminophen overdose

This clinical policy focuses on critical issues concerning the management of patients presenting to the emergency department (ED) with acetaminophen overdose. The subcommittee reviewed the medical literature relevant to the questions posed. The critical questions are: 1. What are the indications for N-acetylcysteine (NAC) in the acetaminophen overdose patient with a known time of acute ingestion who can be risk stratified by th Rumack-Matthew nomogram? 2. What are the indications for NAC in the acetaminophen overdose patient who cannot be risk stratified by the Rumack-Matthew nomogram? Recommendations are provided on the basis of the strength of evidence of the literature. Level A recommendations represent patient management principles that reflect a high degree of clinical certainty; Level B recommendations represent patient management principles that reflect moderate clinical certainty; and Level C recommendations represent other patient management strategies that are based on preliminary, inconclusive, or conflicting evidence, or based on committee consensus. This guideline is intended for physicians working in EDs.

Clinical policy: critical issues in the management of patients presenting to the emergency department with acetaminophen overdose

This clinical policy focuses on critical issues concerning the management of patients presenting to the emergency department (ED) with acetaminophen overdose. The subcommittee reviewed the medical literature relevant to the questions posed. The critical questions are: 1. What are the indications for N-acetylcysteine (NAC) in the acetaminophen overdose patient with a known time of acute ingestion who can be risk stratified by the Rumack-Matthew nomogram? 2. What are the indications for NAC in the acetaminophen overdose patient who cannot be risk stratified by the Rumack-Matthew nomogram? Recommendations are provided on the basis of the strength of evidence of the literature. Level A recommendations represent patient management principles that reflect a high degree of clinical certainty; Level B recommendations represent patient management principles that reflect moderate clinical certainty; and Level C recommendations represent other patient management strategies that are based on preliminary, inconclusive, or conflicting evidence, or based on committee consensus. This guideline is intended for physicians working in EDs.

Acetaminophen poisoning: an evidence-based consensus guideline for out-of-hospital management

The objective of this guideline is to assist poison center personnel in the appropriate out-of-hospital triage and initial management of patients with suspected ingestions of acetaminophen. An evidence-based expert consensus process was used to create this guideline. This guideline applies to ingestion of acetaminophen alone and is based on an assessment of current scientific and clinical information. The expert consensus panel recognizes that specific patient care decisions may be at variance with this guideline and are the prerogative of the patient and the health professionals providing care. The panel's recommendations follow. These recommendations are provided in chronological order of likely clinical use. The grade of recommendation is provided in parentheses. 1) The initial history obtained by the specialist in poison information should include the patient's age and intent (Grade B), the specific formulation and dose of acetaminophen, the ingestion pattern (single or multiple), duration of ingestion (Grade B), and concomitant medications that might have been ingested (Grade D). 2) Any patient with stated or suspected self-harm or who is the recipient of a potentially malicious administration of acetaminophen should be referred to an emergency department immediately regardless of the amount ingested. This referral should be guided by local poison center procedures (Grade D). 3) Activated charcoal can be considered if local poison center policies support its prehospital use, a toxic dose of acetaminophen has been taken, and fewer than 2 hours have elapsed since the ingestion (Grade A). Gastrointestinal decontamination could be particularly important if acetylcysteine cannot be administered within 8 hours of ingestion. Acute, single, unintentional ingestion of acetaminophen: 1) Any patient with signs consistent with acetaminophen poisoning (e.g., repeated vomiting, abdominal tenderness in the right upper quadrant or mental status changes) should be referred to an emergency department for evaluation (Grade D). 2) Patients less than 6 years of age should be referred to an emergency department if the estimated acute ingestion amount is unknown or is 200 mg/kg or more. Patients can be observed at home if the dose ingested is less than 200 mg/kg (Grade B). 3) Patients 6 years of age or older should be referred to an emergency department if they have ingested at least 10 g or 200 mg/kg (whichever is lower) or when the amount ingested is unknown (Grade D). 4) Patients referred to an emergency department should arrive in time to have a stat serum acetaminophen concentration determined at 4 hours after ingestion or as soon as possible thereafter. If the time of ingestion is unknown, the patient should be referred to an emergency department immediately (Grade D). 5) If the initial contact with the poison center occurs more than 36 hours after the ingestion and the patient is well, the patient does not require further evaluation for acetaminophen toxicity (Grade D). Repeated supratherapeutic ingestion of acetaminophen (RSTI): 1) Patients under 6 years of age should be referred to an emergency department immediately if they have ingested: a) 200 mg/kg or more over a single 24-hour period, or b) 150 mg/kg or more per 24-hour period for the preceding 48 hours, or c) 100 mg/kg or more per 24-hour period for the preceding 72 hours or longer (Grade C). 2) Patients 6 years of age or older should be referred to an emergency department if they have ingested: a) at least 10 g or 200 mg/kg (whichever is less) over a single 24-hour period, or b) at least 6 g or 150 mg/kg (whichever is less) per 24-hour period for the preceding 48 hours or longer. In patients with conditions purported to increase susceptibility to acetaminophen toxicity (alcoholism, isoniazid use, prolonged fasting), the dose of acetaminophen considered as RSTI should be greater than 4 g or 100 mg/kg (whichever is less) per day (Grade D). 3) Gastrointestinal decontamination is not needed (Grade D). Other recommendations: 1) The out-of-hospital management of extended-release acetaminophen or multi-drug combination products containing acetaminophen is the same as an ingestion of acetaminophen alone (Grade D). However, the effects of other drugs might require referral to an emergency department in accordance with the poison center's normal triage criteria. 2) The use of cimetidine as an antidote is not recommended (Grade A).

Acetaminophen Poisoning

Acetaminophen (acetyl-para-amino-phenol or APAP), an antipyretic and analgesic, is a common component in hundreds of over-the-counter and prescription medications. The wide usage of this drug results in many potentially toxic exposures. It is therefore critical for the clinician to be comfortable with the diagnosis and treatment of APAP toxicity. Prompt recognition of APAP overdose and institution of appropriate therapy are essential to preventing morbidity and mortality.

Updates on acetaminophen toxicity

APAP is likely to remain a common toxic exposure and continue to cause significant morbidity and mortality. To minimize the harm to patients, it is necessary for the clinician to be aware of the current diagnostic and therapeutic management of APAP poisoning. Despite the bulk of literature on APAP, management strategies are likely to continue to change as more studies are conducted to improve our understanding of nonacute ingestions and the role of prognostic markers in defining those most at risk for life-threatening hepatotoxicity.

The Safety Profile of Sustained Release Paracetamol During Therapeutic Use and Following Overdose

Sustained release (SR) formulations of paracetamol (acetaminophen) have been introduced in several countries to provide lasting pain relief and reduced risk of rebound pain. However, few studies have evaluated the safety of paracetamol SR formulations. To assess the available published safety data regarding SR formulations of paracetamol, the EMBASE and MEDLINE databases were searched from 1980 to June 2003 for published worldwide human experience with paracetamol SR formulations. All publications that included any information about ingestion of any paracetamol SR formulation were systematically reviewed and abstracted by trained staff. The literature searches returned a total of 14 references containing safety data on paracetamol SR. In addition, the Toxic Exposure Surveillance System (TESS) of the American Association of Poison Control Centers (AAPCC) database was searched for human exposure cases. The TESS database yielded 3003 cases from 1994 to 2002 that involved a paracetamol SR product. The available information indicates that the adverse event and safety profile of paracetamol SR is very similar to immediate release (IR) formulations of paracetamol. During therapeutic use, minor effects such as gastrointestinal upset and headache may occur. The rate of these effects varies substantially among studies but overall does not appear to be different between the SR and IR formulations of paracetamol. Overdose with paracetamol SR is expected to cause liver injury similar to overdose with IR formulations. The number of human exposure cases has increased since introduction of the SR formulation; however, sales of the SR formulation amounted to 7.5% of all paracetamol sales but accounted for 2.5% of the cases reported to poison centres. There were two deaths recorded in the TESS database: both were the result of multiple drug ingestion. No cases of death or unusual types of toxicity have been described from an overdose of paracetamol SR alone.

Poisonings and overdoses in the intensive care unit: General and specific management issues

OBJECTIVE

To provide current information on general and specific interventions for overdoses likely to require intensive care.

DESIGN

Review of literature relevant to selected interventions for general management of overdoses and specific poisons.

RESULTS

The benefit of interventions to decrease absorption or enhance elimination of toxins is limited to a relatively small number of specific agents. Antidotes and certain interventions may be helpful in preventing or treating toxicity in specific poisonings when used appropriately. Intensive supportive care is also necessary to achieve good outcomes.

CONCLUSION

Knowledge of the indications and limitations of current interventions for poisonings and overdoses is important for care of the critically ill poisoned patient.

Acetaminophen hepatotoxicity

Unlike the bulk of medications, described in this fascicle, that cause liver injury in humans, acetaminophen is a non-prescription drug that can be purchased in drug stores and supermarkets without a physician's involvement. Death or severe injury is far more likely to occur with its use than with all the other medications considered in this study. Whereas attempts to control the quantity of drug ingested have been made in the United Kingdom and elsewhere in Europe, no comparable moves have taken place in the United States. The Food and Drug Administration claims to have concerns about the situation, however, but has yet to make an effort to more closely regulate the marketing and distribution of the drug. It is to be hoped that this will not be the case by the time the next issue of Drug Hepatotoxicity is scheduled for this series.

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.