Interventions for paracetamol (acetaminophen) overdoses

Liver Protection of a Low-Polarity Fraction from Ficus pandurata Hance, Prepared by Supercritical CO2 Fluid Extraction, on CCl4-Induced Acute Liver Injury in Mice via Inhibiting Apoptosis and Ferroptosis Mediated by Strengthened Antioxidation

Ficus pandurata Hance (FPH) is a Chinese herbal medicine widely used for health care. This study was designed to investigate the alleviation efficacy of the low-polarity ingredients of FPH (FPHLP), prepared by supercritical CO₂ fluid extraction technology, against CCl₄-induced acute liver injury (ALI) in mice and uncover its underlying mechanism. The results showed that FPHLP had a good antioxidative effect determined by the DPPH free radical scavenging activity test and T-AOC assay. The in vivo study showed that FPHLP dose-dependently protected against liver damage via detection of ALT, AST, and LDH levels and changes in liver histopathology. The antioxidative stress properties of FPHLP suppressed ALI by increasing levels of GSH, Nrf2, HO-1, and Trx-1 and reducing levels of ROS and MDA and the expression of Keap1. FPHLP significantly reduced the level of Fe²⁺ and expression of TfR1, xCT/SLC7A11, and Bcl2, while increasing the expression of GPX4, FTH1, cleaved PARP, Bax, and cleaved caspase 3. The results demonstrated that FPHLP protected mouse liver from injury induced by CCl₄ via suppression of apoptosis and ferroptosis. This study suggests that FPHLP can be used for liver damage protection in humans, which strongly supports its traditional use as a herbal medicine.

Scalable synthesis and validation of PAMAM dendrimer-N-acetyl cysteine conjugate for potential translation

Dendrimer-N-acetyl cysteine (D-NAC) conjugate has shown significant promise in multiple preclinical models of brain injury and is undergoing clinical translation. D-NAC is a generation-4 hydroxyl-polyamidoamine dendrimer conjugate where N-acetyl cysteine (NAC) is covalently bound through disulfide linkages on the surface of the dendrimer. It has shown remarkable potential to selectively target and deliver NAC to activated microglia and astrocytes at the site of brain injury in several animal models, producing remarkable improvements in neurological outcomes at a fraction of the free drug dose. Here we present a highly efficient, scalable, greener, well-defined route to the synthesis of D-NAC, and validate the structure, stability and activity to define the benchmarks for this compound. This newly developed synthetic route has significantly reduced the synthesis time from three weeks to one week, uses industry-friendly solvents/reagents, and involves simple purification procedures, potentially enabling efficient scale up.

Interventions for paracetamol (acetaminophen) overdose

BACKGROUND

Paracetamol (acetaminophen) is the most widely used non-prescription analgesic in the world. Paracetamol is commonly taken in overdose either deliberately or unintentionally. In high-income countries, paracetamol toxicity is a common cause of acute liver injury. There are various interventions to treat paracetamol poisoning, depending on the clinical status of the person. These interventions include inhibiting the absorption of paracetamol from the gastrointestinal tract (decontamination), removal of paracetamol from the vascular system, and antidotes to prevent the formation of, or to detoxify, metabolites.

OBJECTIVES

To assess the benefits and harms of interventions for paracetamol overdosage irrespective of the cause of the overdose.

SEARCH METHODS

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register (January 2017), CENTRAL (2016, Issue 11), MEDLINE (1946 to January 2017), Embase (1974 to January 2017), and Science Citation Index Expanded (1900 to January 2017). We also searched the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov database (US National Institute of Health) for any ongoing or completed trials (January 2017). We examined the reference lists of relevant papers identified by the search and other published reviews.

SELECTION CRITERIA

Randomised clinical trials assessing benefits and harms of interventions in people who have ingested a paracetamol overdose. The interventions could have been gastric lavage, ipecacuanha, or activated charcoal, or various extracorporeal treatments, or antidotes. The interventions could have been compared with placebo, no intervention, or to each other in differing regimens.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from the included trials. We used fixed-effect and random-effects Peto odds ratios (OR) with 95% confidence intervals (CI) for analysis of the review outcomes. We used the Cochrane 'Risk of bias' tool to assess the risks of bias (i.e. systematic errors leading to overestimation of benefits and underestimation of harms). We used Trial Sequential Analysis to control risks of random errors (i.e. play of chance) and GRADE to assess the quality of the evidence and constructed 'Summary of findings' tables using GRADE software.

MAIN RESULTS

We identified 11 randomised clinical trials (of which one acetylcysteine trial was abandoned due to low numbers recruited), assessing several different interventions in 700 participants. The variety of interventions studied included decontamination, extracorporeal measures, and antidotes to detoxify paracetamol's toxic metabolite; which included methionine, cysteamine, dimercaprol, or acetylcysteine. There were no randomised clinical trials of agents that inhibit cytochrome P-450 to decrease the activation of the toxic metabolite N-acetyl-p-benzoquinone imine.Of the 11 trials, only two had two common outcomes, and hence, we could only meta-analyse two comparisons. Each of the remaining comparisons included outcome data from one trial only and hence their results are presented as described in the trials. All trial analyses lack power to access efficacy. Furthermore, all the trials were at high risk of bias. Accordingly, the quality of evidence was low or very low for all comparisons. Interventions that prevent absorption, such as gastric lavage, ipecacuanha, or activated charcoal were compared with placebo or no intervention and with each other in one four-armed randomised clinical trial involving 60 participants with an uncertain randomisation procedure and hence very low quality. The trial presented results on lowering plasma paracetamol levels. Activated charcoal seemed to reduce the absorption of paracetamol, but the clinical benefits were unclear. Activated charcoal seemed to have the best risk:benefit ratio among gastric lavage, ipecacuanha, or supportive treatment if given within four hours of ingestion. There seemed to be no difference between gastric lavage and ipecacuanha, but gastric lavage and ipecacuanha seemed more effective than no treatment (very low quality of evidence). Extracorporeal interventions included charcoal haemoperfusion compared with conventional treatment (supportive care including gastric lavage, intravenous fluids, and fresh frozen plasma) in one trial with 16 participants. The mean cumulative amount of paracetamol removed was 1.4 g. One participant from the haemoperfusion group who had ingested 135 g of paracetamol, died. There were no deaths in the conventional treatment group. Accordingly, we found no benefit of charcoal haemoperfusion (very low quality of evidence). Acetylcysteine appeared superior to placebo and had fewer adverse effects when compared with dimercaprol or cysteamine. Acetylcysteine superiority to methionine was unproven. One small trial (low quality evidence) found that acetylcysteine may reduce mortality in people with fulminant hepatic failure (Peto OR 0.29, 95% CI 0.09 to 0.94). The most recent randomised clinical trials studied different acetylcysteine regimens, with the primary outcome being adverse events. It was unclear which acetylcysteine treatment protocol offered the best efficacy, as most trials were underpowered to look at this outcome. One trial showed that a modified 12-hour acetylcysteine regimen with a two-hour acetylcysteine 100 mg/kg bodyweight loading dose was associated with significantly fewer adverse reactions compared with the traditional three-bag 20.25-hour regimen (low quality of evidence). All Trial Sequential Analyses showed lack of sufficient power. Children were not included in the majority of trials. Hence, the evidence pertains only to adults.

AUTHORS' CONCLUSIONS

These results highlight the paucity of randomised clinical trials comparing different interventions for paracetamol overdose and their routes of administration and the low or very low level quality of the evidence that is available. Evidence from a single trial found activated charcoal seemed the best choice to reduce absorption of paracetamol. Acetylcysteine should be given to people at risk of toxicity including people presenting with liver failure. Further randomised clinical trials with low risk of bias and adequate number of participants are required to determine which regimen results in the fewest adverse effects with the best efficacy. Current management of paracetamol poisoning worldwide involves the administration of intravenous or oral acetylcysteine which is based mainly on observational studies. Results from these observational studies indicate that treatment with acetylcysteine seems to result in a decrease in morbidity and mortality, However, further evidence from randomised clinical trials comparing different treatments are needed.

A cost effectiveness analysis of the preferred antidotes for acute paracetamol poisoning patients in Sri Lanka

Background

Acute paracetamol poisoning is a rapidly increasing problem in Sri Lanka. The antidotes are expensive and yet no health economic evaluation has been done on the therapy for acute paracetamol poisoning in the developing world. The aim of this study is to determine the cost effectiveness of using N-acetylcysteine over methionine in the management of acute paracetamol poisoning in Sri Lanka.

Methods

Economic analysis was applied using public healthcare system payer perspective.

Costs were obtained from a series of patients admitted to the National Hospital of Sri Lanka with a history of acute paracetamol overdose. Evidence on effectiveness was obtained from a systematic review of the literature. Death due to hepatotoxicity was used as the primary outcome of interest. Analysis and development of decision tree models was done using Tree Age Pro 2008.

Results

An affordable treatment threshold of Sri Lankan rupees 1,537,120/death prevented was set from the expected years of productive life gained and the average contribution to GDP. A cost-minimisation analysis was appropriate for patients presenting within 10 hours and methionine was the least costly antidote. For patients presenting 10-24 hours after poisoning, n-acetylcysteine was more effective and the incremental cost effectiveness ratio of Sri Lankan rupees 316,182/life saved was well under the threshold. One-way and multi-way sensitivity analysis also supported methionine for patients treated within 10 hours and n-acetylcysteine for patients treated within 10-24 hours as preferred antidotes.

Conclusions

Post ingestion time is an important determinant of preferred antidotal therapy for acute paracetamol poisoning patients in Sri Lanka. Using n-acetylcysteine in all patients is not cost effective. On economic grounds, methionine should become the preferred antidote for Sri Lankan patients treated within 10 hours of the acute ingestion and n-acetylcysteine should continue to be given to patients treated within 10-24 hours.

Treatment in the pediatric emergency department is evidence based: a retrospective analysis

BACKGROUND

Our goal was to quantify the evidence that is available to the physicians of a pediatric emergency department (PED) in making treatment decisions. Further, we wished to ascertain what percentage of evidence for treatment provided in the PED comes from pediatric studies.

METHODS

We conducted a retrospective chart review of randomly selected patients seen in the PED between January 1 and December 31, 2002. The principal investigator identified a primary diagnosis and primary intervention for each chart. A thorough literature search was then undertaken with respect to the primary intervention. If a randomized control trial (RCT) or a systematic review was found, the intervention was classified as level I evidence. If no RCT was found, the intervention was assessed by an expert committee who determined its appropriateness based on face validity (RCTs were unanimously judged to be both unnecessary and, if a placebo would have been involved, unethical). These interventions were classified as level II evidence. Interventions that did not fall into either above category were classified as level III evidence.

RESULTS

Two hundred and sixty-two patient charts were reviewed. Of these, 35.9% did not receive a primary intervention. Of the 168 interventions assessed, 80.4% were evidence-based (level I), 7.1% had face validity (level II) and 12.5% had no supporting evidence (level III). Of the evidence-based interventions, 83.7% were supported by studies with mostly pediatric patients.

CONCLUSION

Our study demonstrates that a substantial proportion of PED treatment decisions are evidence-based, with most based on studies in pediatric patients. Also, a large number of patients seen in the PED receive no intervention.

Agreement between reported use of interventions for liver diseases and research evidence in Cochrane systematic reviews

BACKGROUND/AIMS

This study evaluates the agreement between reported use of interventions for patients with liver diseases and research evidence in Cochrane systematic reviews.

METHODS

In July 2002, the Cochrane Hepato-Biliary Group had completed 28 systematic reviews on 36 interventions that were available in Denmark. Based on the reviews, three interventions (n-acetylcysteine for paracetamol overdose, terlipressin for bleeding oesophageal varices, and antibiotics for patients with cirrhosis and gastrointestinal bleeding) with significant beneficial effects on clinical outcomes were classified as 'evidence-based', whereas 19 were classified as 'possibly evidence-based', and 14 as 'not evidence-based'. Questionnaires on reported use and perceived intervention effects were mailed to 108 physicians practising in Danish hospitals. Sixty-six returned their questionnaire.

RESULTS

The proportion of physicians who reported that they never used the three evidence-based interventions varied considerably (2, 62, and 57%, respectively). The perceived intervention effect, duration of clinical experience, employment as head of department, and university hospital employment were significant predictors of more frequent use of evidence-based interventions. Physicians also reported that they used the interventions that were not evidence-based more often if they were employed at a university hospital.

CONCLUSIONS

Considerable disagreements between reported use and research evidence were identified. Additional research on methods to introduce evidence-based medicine in practice seems warranted.

Deliberate self-poisoning with acetaminophen: a comparison with other medications

BACKGROUND

Acetaminophen is the most common drug employed in deliberate self-poisoning (DSP) in many countries and can lead to acute liver failure. The purpose of the present study was to compare DSP with acetaminophen with DSP with other medications.

METHODS

From January 2001 to December 2002, all patients admitted after DSP to Soroka University Hospital in Beer-Sheva, Israel, were identified. Demographic data and medical history were obtained retrospectively.

RESULTS

There were 282 incidences of DSP in the study period. The mean age of 94 patients with an acetaminophen overdose was lower than that of patients who had attempted DSP with other medications (24.8 vs. 34.6 years, p<0.001). There was no gender or ethnic difference between the groups. Patients with DSP with acetaminophen were less likely to make recurrent attempts (23.4% vs. 39.9% p=0.006), less likely to have psychiatric disorders (32% vs. 59% p<0.001), and had a shorter hospital stay (1.7 vs. 2.1 days, p=0.05). The acetaminophen group had less of an impairment in level of consciousness (84% vs. 52.1% p<0.001) and had less need for ICU care (6.4% vs. 14.9%, p=0.04). Serum levels were checked in 68 (72.3%) of the patients in the acetaminophen group and they were found to be high in 6 (8.8%) of them (95% CI 2.1-15.5%).

CONCLUSION

Taking an overdose of acetaminophen is a common method of DSP, with patients tending to have a more benign presentation and shorter hospital stay than those who attempt DSP with other medications. Further research on the optimal care of these patients and multi-disciplinary approaches to DSP prevention are needed.

Acute Liver Failure

Acute liver failure (ALF) is an uncommon medical emergency whose rapid progression and high mortality demand early diagnosis and expert management, including immediate transfer of any potential case to facilities for intensive care and orthotopic liver transplantation (OLT). All patients with ALF must be screened aggressively for acetaminophen toxicity (history, serum levels, "hyperacute" presentation with renal failure), for other drugs, and viral hepatitis; rare causes of ALF should also be considered. After an acetaminophen overdose, N-acetylcysteine must be given as early as possible, preferably in the emergency room, but any patient with ALF should promptly receive N-acetylcysteine if there is suspicion of acetaminophen toxicity irrespective of the time of ingestion. Supportive care for all patients with ALF includes adequate enteral nutrition, aggressive screening and treatment of infection, prophylactic broad-spectrum antibiotics, and antifungal agents. Sedation with propofol is given for severe agitation or mechanical ventilation. With advanced coma grades, intensive care is needed with hemodynamic monitoring, ventilatory support, continuous renal replacement for renal failure, and intracranial pressure monitoring. Intracranial hypertension is treated with mannitol and/or acute short-term hyperventilation, but if the patient is refractory to treatment, mild-moderate hypothermia is achieved by a cooling blanket that is continued throughout OLT. Barbiturate coma is only used in refractory cases as the last treatment modality. Seizures are aggressively treated with phenytoin, with additional diazepam as needed. Candidacy and activation for OLT should be completed as early as possible in the course of ALF, especially in "hyperacute" cases such as acetaminophen toxicity. The final decision to proceed with OLT is made when a donor organ becomes available. King's College Hospital criteria for OLT are still the best prognostic assessment for fatal outcome in ALF, but the criteria fail to identify some patients who will die.

A randomized controlled trial of intravenous N-acetylcysteine for the prevention of contrast-induced nephropathy after cardiac catheterization: lack of effect

BACKGROUND

Contrast-induced nephropathy (CIN) after cardiac catheterization is common in patients with preexisting renal dysfunction. Studies of oral acetylcysteine to prevent CIN have produced conflicting results. Intravenous N-acetylcysteine (NAC) has logistic advantages in this setting. The objective of this study was to evaluate, in a blinded, randomized, placebo-controlled fashion, whether intravenous NAC reduced CIN in the setting of cardiac catheterization in patients with preexisting renal insufficiency.

METHODS

Patients with renal dysfunction undergoing cardiac catheterization were randomly assigned to intravenous NAC 500 mg immediately before the procedure or placebo. All patients received isotonic saline (200 mL) beforehand, followed by 1.5 mL/kg per hour for 6 hours, unless contraindicated. Exclusion criteria included acute renal failure, creatinine >400 micromol/L, concurrent dialysis, unstable clinical status, and prior NAC use. Baseline creatinine was obtained immediately before the procedure and repeated 2 to 8 days later. The primary end point was the occurrence of CIN defined as a reduction in creatinine clearance from baseline of >5 mL/min (Cockcroft-Gault formula).

RESULTS

The study was terminated early because of a determination of futility by the Data Safety Monitoring Committee after enrollment of 487 patients. The median baseline creatinine clearance was 44 mL/min (interquartile range, 33, 55). Median contrast received was 120 mL (interquartile range, 80, 175). Baseline characteristics were similar in the two groups. Altogether, 98 (22.0%) subjects had the primary end point: 23.3% in the NAC group and 20.7% in the placebo arm (P =.57).

CONCLUSIONS

In this large, randomized trial, enrolling a high-risk group of patients with impaired renal function, intravenous NAC was ineffective in preventing CIN.