Epidemiology, management and outcome of paracetamol poisoning in an inner city emergency department

N-Acetylcysteine for Preventing Acetaminophen-Induced Liver Injury: A Comprehensive Review

Aims: N-Acetylcysteine (NAC) is used as an antidote in acetaminophen (APAP) overdose to prevent and mitigate drug-induced liver injury (DILI). Our objective was to systematically review evidence of the use of NAC as a therapeutic option for APAP overdose and APAP-related DILI in order to define the optimal treatment schedule and timing to start treatment.

Methods: Bibliographic databases (PubMed, Web of Science, Embase, and MEDLINE) were searched for retrospective and prospective cohort studies, case series, and clinical trials. The prespecified primary outcomes were DILI-related mortality, hepatotoxicity, and adverse events (AEs).

Results: In total, 34 studies of NAC usage in APAP-related DILI cases with 19,580 patients were identified, of which 2,376 patients developed hepatotoxicities. The mortality rate across different studies ranged from 0 to 52%. Large variability of NAC regimens was found, i.e., intravenous (I.V.) (100–150 mg/kg) and oral (70–140 mg/kg), and length of treatment varied—12, 24, or 48 h for I.V. regimen and 72 h for oral administration. The timing of initiation of NAC treatment showed different results in terms of occurrence of hepatotoxicity and mortality; if started within 8 h and no more than 24 h from APAP overdose, either intravenously or orally, NAC administration was efficacious in terms of mortality. The most frequent AEs reported were anaphylactic reactions, followed by cutaneous AEs for the IV route and intestinal AEs for the oral one.

Conclusion: NAC improves hepatotoxicity and reduces mortality. Timing of treatment, ranging from 8 to 24 h from APAP overdose, regardless of the regimen or route of administration, is important to prevent or minimize liver damage, particularly in children and in elderly and obese patients.

Changes in Epidemiology of Acetaminophen Overdoses in an Urban County Hospital After 20 Years

INTRODUCTION

Acetaminophen (APAP) toxicity is the main cause of acute liver failure in the United States. A prior series (1992-1995) identified 71 hospitalized adults with APAP toxicity through the International Statistical Classification of Disease and Related Health Problems, 9th revision (ICD-9) code at Parkland Hospital, Dallas, TX.

METHODS

We used a laboratory database search of serum APAP levels from 2011 to 2015 to identify patients with APAP toxicity in the same hospital.

RESULTS

We identified 140 patients hospitalized for APAP toxicity from 27,143 APAP levels obtained; 35 required Intensive Care Unit (ICU) admission, and there were no deaths. APAP toxicity/100,000 admissions was similar between eras.

DISCUSSION

APAP toxicity continues unabated after 20 years but with improved overall outcomes.

Paracetamol poisoning: a population-based study from Iceland

OBJECTIVE

To examine the incidence and severity of paracetamol poisoning in a population-based cohort in Iceland. A previous study showed a decrease in the incidence during a financial crisis in Iceland, by approximately half (16/100,000 annually). The aims of the study were to assess the incidence and nature of paracetamol poisoning after economic recovery in Iceland and to compare intentional and accidental poisoning.

METHODS

Paracetamol serum concentrations were used to identify patients in this retrospective study from 2010-2017. A search was undertaken in laboratory databases for patients with serum paracetamol concentrations, which were grouped by <66 µmol/L (below detection limit) and ≥66 µmol/L. Medical records were reviewed and relevant laboratory and clinical information obtained to determine whether paracetamol poisoning had occurred.

RESULTS

Altogether 542 cases of paracetamol poisoning were identified. The mean annual incidence was 27/100,000 (range 22-33). Intentional poisoning was observed in 437/542 (81%) cases, most frequently among females 16-25 years of age. Males ≥65 years were more likely to overdose by accident, which was associated with worse outcomes. Twenty-five (4.6%) patients developed severe paracetamol-induced liver injury and coagulopathy. Overall, six (1.1%) cases were fatal in which paracetamol contributed to the cause of death, with accidental poisoning found in 67% (4/6).

CONCLUSIONS

The incidence of paracetamol poisoning has increased in recent years associated with economic recovery in Iceland. Most patients had favourable outcomes. Intentional overdose was most common in young females, whereas accidental overdose was more common in older males and more frequently associated with a fatal outcome.

Restriction of non-opioid analgesics sold over-the-counter in Denmark: A national study of impact on poisonings

OBJECTIVE

Self-poisoning with non-opioid analgesics presents a growing challenge to health care providers. We aimed to assess the impact of an 18-year age restriction of OTC sales and a pack size restriction of non-opioid analgesics sold OTC in pharmacies on hospital-treated poisonings and poisoning severity measured using biomarkers.

METHODS

We applied a before and after design using interrupted time series analysis. Data on all poisonings recorded as hospital admissions were obtained during 2002-2015 and biochemical parameters from laboratory databases during 2011-2015, both covering the entire Danish population.

RESULTS

The age restriction was followed by a 17% level reduction in admissions for non-opioid analgesic poisoning among young people age 10-17 years (RR 0.830; 95% CI 0.697-0.988; p < 0.036). After the pack size restriction, an instant level reduction of 18.5% (RR 0.815; 95% CI 0.729-0.912; p < 0.001) was observed for the entire population. A 27% decrease in the number of poisonings with alanine transaminase levels (ALT) ≥ 210 U/L was observed (RR 0.734; 95% CI 0.579-0.931; p = 0.011) followed by 40% decrease in biomarkers indicative of liver failure (RR 0.597; 95% CI 0.421-0.847; p = 0.004). We also observed similar reductions for other poisonings such as psychotropics.

LIMITATIONS

Although declines in poisonings were observed after implementation of means restrictive measures, a causal link cannot be inferred.

CONCLUSION

Age and pack size restriction were assiociated with a reduction in the numbers of poisonings. This was also observed for pharmaceutical poisonings in general, which might suggest a non-specific or spill-over effect.

Characteristics of patients presenting post-suicide attempt to an Academic Medical Center Emergency Department in Lebanon

BACKGROUND

Emergency Department (ED) visits for suicide attempts have been described worldwide; however, the populations studied were predominantly Western European, North American, or East Asian. This study aims to describe the epidemiology of ED patients presenting post-suicide attempt to an academic medical center in Lebanon and to report on factors that affect ED disposition.

METHODS

A retrospective cohort study was conducted between 2009 and 2015. Patients of any age group were included if they had presented to the ED after a suicide attempt. Patients with unintentional self-harm were excluded. Descriptive analysis was performed on the demographics and characteristics of suicide attempts of the study population. A bivariate analysis to compare the two groups (hospitalized or discharged) was conducted using Student's t test and Pearson Chi-square where appropriate. A multivariate analysis was then conducted to determine the predictors of hospital admission.

RESULTS

One hundred and eight patients were included in the final analysis. Most patients were females (71.4%) and between 22 and 49 years of age. A considerable number of patients were unemployed (43%), unmarried (61.1%), and living with family (86.9%). Most suicide attempts were performed at home (93.5%) and on a weekday (71.3%). The most common mechanisms of injury were overdose with prescription medications (61.3%), overdose with over-the-counter drugs (27.9%), and self-inflicted lacerations (10.1%). The classes of medication most commonly abused were benzodiazepines (39.3%) followed by acetaminophen (27.3%). A large portion of our patients were admitted (70.3%), with the majority going to the psychiatric ward (71.1%). Of note, a quarter (27.5%) of our patients left the ED against medical advice, with 23.5% of admitted patients leaving the hospital before completion of treatment. The main predictors of admission were found to be overdose on prescription medications OR 9.25 (2.12-40.42 CI95%).

CONCLUSIONS

The characteristics of our suicide attempters mirror those of international and regional suicide attempters. Further work is required to quantify the effect of voluntary refusal of hospital treatment, the repercussions of family, and financial barriers to healthcare and suicide as a whole in our society.

Increased acetaminophen related calls to Finnish PIC better reflect acetaminophen sales than serious poisonings

OBJECTIVE

Acetaminophen (APAP) or paracetamol is a commonly encountered medicine in poisonings. We studied the changes in APAP related calls to the Finnish poison information centre (FPIC), and serious intoxications, involving hepatotoxicity or death in 2001-2014. These data were compared with paracetamol sales in Finland.

METHODS

This is a retrospective analysis of the FPIC database calls, national cause of death registry, registries of liver transplantations and molecular adsorbent recycling system (MARS)-treated patients from Helsinki University Hospital together with the National Institute of Health and Welfare registry of patients hospitalized. Data on APAP sales were obtained from the Finnish Medicines Agency.

RESULTS

Between 2001 and 2014, the number of calls/year related to human APAP exposures to the FPIC increased from 227 to 1058. No change in the age distribution of enquiries was seen. Most calls involved minors: 58% (range 52-64%) for children under 6 years old, and 9% (range 6-14%) for children of 6-15 years. In Finland, APAP related fatalities have gradually increased from an average of 7/year (range 4-10) in 2000-2005 to an average of 11/year (range 6-17) in 2010-2013, whereas the number of liver transplantations remained low, average 0.6/year (range 0-2). For patients in need of MARS-treatment, a slight decrease was seen. Total APAP sales increased from 5.6 (47% prescription, 53% OTC) to 29.7 (81% prescription, 19% OTC). DDD/1000 inhabitants/day from 2001 to 2014 is recorded. Best linear relationship (R² = 0.97; p < .001) was observed between total FPIC calls and total sales of APAP in 2001-2014. Fatalities show a weaker relationship with sales (R² = 0.317; p = .045).

CONCLUSIONS

During the study period, we see an increase in FPIC exposure calls accompanied by an increase in APAP sales. Changes in the chosen indicators for serious poisonings show only a weak association. Despite an evident trend between sales and fatalities, the correlation with fatality remains weak due to the small number of fatalities.

A population-based study of risk perceptions of paracetamol use among Swedes-with a special focus on young adults

PURPOSE

The purpose of this study was to investigate risk perceptions of paracetamol use, with a special focus on young adults.

METHODS

A web survey was sent to a representative sample (n = 5838) of the Swedish adult population. Altogether, 3120 persons answered the full questionnaire. Risk perceptions of paracetamol use in relation to sex, age, and education were determined using logistic regression.

RESULTS

Most respondents (70.5%) reported use of paracetamol in the 3 months prior to the study; the highest proportion was found among those aged 18 to 25 years (75.8%). Nine in 10 were over-the-counter (OTC) paracetamol users. A total of 14.2% thought paracetamol is completely harmless to use while 54.3% indicated risks associated with use even when following the dosing instructions. One third disagreed that it is less risky to use paracetamol compared with nonsteroidal antiinflammatory drugs. Three-quarters identified liver damage as a potential consequence of exceeding the recommended maximum daily dose. The likelihood of a high-risk perception was higher in women compared with men, and increased with age. No association was found between risk perception and educational status. Participants aged 18 to 25 years had the same ability to identify risks of overdose as did those aged 26 to 65, but expressed more careless attitudes towards use.

CONCLUSIONS

Although the study population purchased paracetamol primarily OTC, they demonstrated basic awareness of paracetamol use including the potential consequences of overdosing. Young adults (18-25 y), who were the most frequent users of OTC paracetamol, perceived less risk associated with use compared with older participants.

Characterisation and outcomes of adult patients with paracetamol overdose presenting to a tertiary hospital in Singapore

INTRODUCTION

Paracetamol is the most common pharmaceutical agent implicated in toxic exposure in Singapore. This study aimed to describe the characteristics of paracetamol overdose in the adult population managed at a tertiary healthcare facility in Singapore.

METHODS

Medical records of adult patients hospitalised with a diagnosis of paracetamol overdose at National University Hospital, Singapore, over a three-year period from January 2011 to December 2013 were retrospectively reviewed.

RESULTS

A total of 177 patients had paracetamol overdose. The median age was 25 years, with a significant female predominance (71.2%). Intentional ingestion accounted for the majority (76.8%) of cases. The median dose of paracetamol ingested was 10 (interquartile range 8-15) g. Among patients who reported ingesting more than 10 g, 46.5% perceived the overdose as non-lethal. N-acetylcysteine was administered in 76.3% of patients, among whom 24.4% experienced an anaphylactoid reaction. Of the 10 (5.6%) patients who had severe hepatotoxicity, 2 (1.1%) developed acute liver failure. Most patients had resolving transaminases at discharge and none required liver transplantation. The median length of hospitalisation was three days. There were no fatalities.

CONCLUSION

Paracetamol overdose occurred predominantly in young adults with intentional ingestion, suggesting that preventive measures targeted at promoting public awareness may not suffice. However, the perceived lack of lethality by many patients who ingested potentially toxic amounts of paracetamol reflects a certain knowledge gap. Healthcare providers should proactively educate consumers on the proper use of paracetamol and the consequences of its overdose.

An assessment of the variation in the concentration of acetylcysteine in infusions for the treatment of paracetamol overdose

BACKGROUND

Intravenous acetylcysteine is the treatment of choice for paracetamol poisoning. A previous UK study in 2001 found that 39% of measured acetylcysteine infusion concentrations differed by >20% from anticipated concentrations. In 2012, the UK Commission on Human Medicines made recommendations for the management of paracetamol overdose, including provision of weight-based acetylcysteine dosing tables. The aim of this study was to assess variation in acetylcysteine concentrations in administered infusions following the introduction of this guidance.

METHODS

A 6-month single-centre prospective study was undertaken at a UK teaching hospital. After preparation, 5-ml samples were taken from the first, second and third/any subsequent acetylcysteine infusions. Acetylcysteine was measured in diluted (1:50) samples by high-performance liquid chromatography. Comparisons between measured and expected concentrations based on prescribed weight-based dose and volume were made for each infusion.

RESULTS

Ninety samples were collected. There was a variation of ≤10% in measured compared to expected concentration for 45 (50%) infusions, of 10-20% for 27 (30%) infusions, 20.1-50% for 14 (16%) infusions and >50% for four (4%) infusions. There was a median (interquartile range) variation in measured compared to expected concentration of -3.6 mg ml^-1 (-6.7 to -2.3) for the first infusion, +0.2 mg ml^-1 (-0.9 to +0.4) for the second infusion and -0.3 mg ml^-1 (-0.6 to +0.2) for third and fourth infusions.

CONCLUSION

There has been a moderate improvement in the variation in acetylcysteine dose administered by infusion. Further work is required to understand the continuing variation and consideration should be given to simplification of acetylcysteine regimes to decrease the risk of administration errors.

Evidence for the changing regimens of acetylcysteine

Paracetamol overdose prior to the introduction of acetylcysteine was associated with significant morbidity. Acetylcysteine is now the mainstay of treatment for paracetamol poisoning and has effectively reduced rates of hepatotoxicity and death. The current three-bag intravenous regimen with an initial high loading dose was empirically derived four decades ago and has not changed since. This regimen is associated with a high rate of adverse effects due mainly to the high initial peak acetylcysteine concentration. Furthermore, there are concerns that the acetylcysteine concentration is not adequate for 'massive' overdoses and that the dose and duration may need to be altered. Various novel regimens have been proposed, looking to address these issues. Many of these modified regimens aim to decrease the rate of adverse reactions by slowing the loading dose and thereby decrease the peak concentration. We used a published population pharmacokinetic model of acetylcysteine to simulate these modified regimens. We determined mean peak and 20 h acetylcysteine concentrations and area under the under the plasma concentration-time curve to compare these regimens. Those regimens that resulted in a lower peak acetylcysteine concentration have been shown in studies to have a lower rate of adverse events. However, these studies were too small to show whether they are as effective as the traditional regimen. Further research is still needed to determine the optimum dose and duration of acetylcysteine that results in the fewest side-effects and treatment failures. Indeed, a more patient-tailored approach might be required, whereby the dose and duration are altered depending on the paracetamol dose ingested or paracetamol concentrations.