Massive acetaminophen overdose: effect of hemodialysis on acetaminophen and acetylcysteine kinetics

Assessment of drug utilization and potentially inappropriate medications in hemodialysis patients with end-stage renal dysfunction: A study in a tertiary care hospital in Bahrain

BACKGROUND

Patients undergoing dialysis pose therapeutic challenges in terms of polypharmacy, administration of potentially inappropriate drugs, and drugs with the potential risk of toxicity.

OBJECTIVE

This study evaluated the use of drugs, potentially inappropriate medicines (PIM), drugs with risk of Torsades de Pointes (TdP), and the complexity of the prescribed regimen using the medication regimen complexity index scale in patients undergoing hemodialysis.

METHODS

A retrospective cohort study was carried out amongst patients receiving hemodialysis. Drugs were classified into one of four classes: (i) drugs used in managing renal complications, (ii) cardiovascular drugs, (iii) anti-diabetic drugs, (iv) drugs for symptomatic management, and (v) others. Drugs were considered as PIM according to the Can-SOLVE CKD working group from a network of Canadian nephrology health professionals. The study adhered to the CredibleMeds classification of drugs with known, possible, and conditional risk of TdP and the complexity of prescribed medicines was evaluated based on the pre-validated medication regimen complexity index scale based on form/route, frequency of dosing, and requirement of special instructions.

RESULTS

Sixty-three participants were included in the study (49 males and 14 females) with the median (range) age of 45 (21-66) years. Cardiovascular drugs followed by drugs used for managing renal complications were the most common classes administered. Notably, 12 (19.1%) patients received one of the non-steroidal anti-inflammatory drugs, 21 (33.3%) received a proton pump inhibitor, three (4.8%) received pregabalin, two (3.2%) received opioid drugs, and one (1.6%) was administered celecoxib. Atorvastatin, furosemide, omeprazole, and allopurinol were the most common PIM drugs administered to the study participants followed by others. Drugs used for symptomatic management had significantly more PIM compared to other classes (p < 0.0001). Six (9.5%) patients received drugs with known TdP risk, one with possible TdP risk, and 61 with conditional risk. Median (range) medical regimen complexity index score was 26.5 (2-62.5).

CONCLUSION

A huge burden of drug therapy was observed in the hemodialysis patients in terms of higher proportions of PIM, complex medical regimen, and prescription of drugs with risk of TdP. Implementation of clinical decision support tools enhancing rational prescription and identification of drugs with TdP risk, introducing antimicrobial stewardship, and stepwise deprescription of the drugs with the least benefit-risk ratio are warranted.

Large paracetamol overdose-Higher dose acetylcysteine is required

Paracetamol poisoning continues to be a worldwide problem and, despite the availability of an effective antidote, acetylcysteine (NAC), the optimal way to use this antidote, particularly following very large doses of paracetamol, has not been established. Recent case series have shown an increased toxicity from high doses of paracetamol, even in those receiving prompt NAC therapy, particularly in patients above the 300 mg/L nomogram treatment line. Clinical trial evidence supporting shorter NAC dosing now allows the possibility for intensifying treatment without the risk of very high rates of ADRs. New biomarkers also show the possibility of early identification of patients at risk of liver injury who might also benefit from increased intensity treatment. This article discusses these data and proposes a logical therapy for increasing NAC dosing which now requires clinical trial testing.

On the Analytic Characteristics of Commercial Acetaminophen Assays in the United States

Background

The management of patients with acetaminophen (APAP) toxicity is largely informed by the blood concentration. We sought to assess the analytical characteristics of past and current commercial APAP assays in the United States.

Methods

We systematically reviewed the analytical characteristics of APAP assays cleared by the Food and Drug Administration’s (FDA) 510(k) premarket notification process by searching the Clinical Laboratory Improvement Amendments (CLIA) database. We collected the following data where available: test principle, precision near 10 mg/L, precision near 150 mg/L, limits of detection, and limits of quantitation.

Results

For all assays, absolute analytical precision decreased as analyte concentration increased. Near [APAP] = 10 mg/L, the most precise assays had a standard deviation (SD) of 0.2 mg/L or coefficient of variation (CV) of 1% and the least precise assays had a SD of 1.8 mg/L or a CV of 10%. Near [APAP] = 150 mg/L, the most precise assay had a SD of 1.4 mg/L or CV of 0.9% and the least precise assays had a SD of 7.4 mg/L or a CV of 4.9%.

Conclusions

Commercially available APAP assays had good analytical precision with improvement over time. The failure of some manufacturers to validate precision near treatment thresholds is concerning. Newer APAP assays can measure a wider range of [APAP], which likely improves the risk stratification of overdose patients but also carries a risk of overdiagnosis when minuscule quantities are detected.

Comparison of intravenous and oral administration of acetaminophen in adults undergoing general anesthesia

BACKGROUND

Acetaminophen is a widely clinically used analgesic. However, the clinical effect of the route of administration on postoperative analgesia as well as on postoperative nausea and vomiting in patients undergoing general anesthesia remains unclear. This study aimed to explore whether the route of administration of acetaminophen affects postoperative analgesia, nausea, and vomiting in patients undergoing general anesthesia.

METHODS

We included all randomized controlled trials investigating the effects of the route of administration of acetaminophen on postoperative pain, nausea, and vomiting in patients undergoing general anesthesia. Independent examiners reviewed the literature and extracted data, with disagreements resolved through negotiation or the involvement of a third party. The Cochrane risk assessment tool was used to evaluate the quality of the included randomized controlled trials. A narrative synthesis was conducted to summarize the qualitative information from the included studies. A meta-integration of quantitative data was performed using RevMan 5.4.

RESULTS

Ten studies met the inclusion criteria. Eight studies assessed postoperative pain, whereas two assessed postoperative nausea and vomiting. Data from the eight studies assessing postoperative pain confirmed that there was no difference between intravenously and orally administered acetaminophen in adults (OR = -0.13; 95% CI, -0.36 to 0.11; p = 0.3). Data from the two studies assessing postoperative nausea and vomiting revealed no difference between intravenously and orally administered acetaminophen in adults (OR = 0.89; 95% CI, 0.64-1.25; p = 0.51). The included studies were of poor quality, with a heterogeneity of 68%.

CONCLUSIONS

No differences in postoperative analgesia or postoperative nausea and vomiting were observed between the routes of administration (intravenous vs. oral) of acetaminophen in adult patients undergoing general anesthesia. There is a need for future large sample studies to increase the reliability of the results.

Massive Acetaminophen Overdose Treated Successfully with N-Acetylcysteine, Fomepizole, and Hemodialysis

Acetaminophen overdose is one of the most common causes of acute hepatic failure in the developed world. There is strong evidence for N-acetylcysteine (NAC) as a safe and effective antidote for acetaminophen toxicity. However, there is less clarity in the management of massive overdoses (acute, single ingestions > 500 mg/kg with 4-hour equivalent concentrations ~6000 μmol/L) which are often associated with metabolic acidosis and multiorgan dysfunction. In such ingestions, the role of adjuvant treatments such as fomepizole and extracorporeal removal is unclear. We present a case of a 20-year-old female presenting with an acute ingestion of over 120 grams (1764.7 mg/kg) and an acetaminophen concentration of 5880 μmol/L who developed refractory shock, decreased level of consciousness, and metabolic acidosis requiring mechanical ventilation and vasopressor support. She was treated with gastric decontamination with activated charcoal, IV NAC, fomepizole, and hemodialysis. The patient had complete clearance of acetaminophen by 32 hours after presentation and normalization of her acid base and hemodynamic status without any organ failure. This case highlights the potential benefit of a triple strategy of NAC, fomepizole, and early hemodialysis in massive acetaminophen overdose, potentially sparing complications of prolonged intubation and ICU hospitalization.

Prognostic nomogram for the severity of acute organophosphate insecticide self-poisoning: a retrospective observational cohort study

OBJECTIVE

To develop a convenient nomogram for the bedside evaluation of patients with acute organophosphorus poisoning (AOPP).

DESIGN

This was a retrospective study.

SETTING

Two independent hospitals in northern China, the First Hospital of Jilin University and the Lequn Hospital of the First Hospital of Jilin University.

PARTICIPANTS

A total of 1657 consecutive patients admitted for the deliberate oral intake of AOPP within 24 hours from exposure and aged >18 years were enrolled between 1 January 2013 and 31 December 2018. The exclusion criteria were: normal range of plasma cholinesterase, exposure to any other type of poisonous drug(s), severe chronic comorbidities including symptomatic heart failure (New York Heart Association III or IV) or any other kidney, liver and pulmonary diseases. Eight hundred and thirty-four patients were included.

PRIMARY OUTCOME MEASURE

The existence of severely poisoned cases, defined as patients with any of the following complications: cardiac arrest, respiratory failure requiring ventilator support, hypotension or in-hospital death.

RESULTS

440 patients from one hospital were included in the study to develop a nomogram of severe AOPP, whereas 394 patients from the other hospital were used for the validation. Associated risk factors were identified by multivariate logistic regression. The nomogram was validated by the area under the receiver operating characteristic curve (AUC). A nomogram was developed with age, white cells, albumin, cholinesterase, blood pH and lactic acid levels. The AUC was 0.875 (95% CI 0.837 to 0.913) and 0.855 (95% CI 0.81 to 0.9) in the derivation and validation cohorts, respectively. The calibration plot for the probability of severe AOPP showed an optimal agreement between the prediction by nomogram and actual observation in both derivation and validation cohorts.

CONCLUSION

A convenient severity evaluation nomogram for patients with AOPP was developed, which could be used by physicians in making clinical decisions and predicting patients' prognosis.

Massive acetaminophen overdose with metabolic acidosis refractory to N-acetylcysteine, fomepizole, and renal replacement therapy

Massive Acetaminophen (N-acetyl-p-aminophenol; APAP) overdose is a common presentation to emergency departments around the world. While N-acetylcysteine (NAC) remains the cornerstone of treatment for APAP overdose, extracorporeal treatment, in the form of renal replacement therapy with intermittent hemodialysis (IHD) or continuous renal replacement therapy (CRRT) may provide benefit in cases associated with altered mental status and metabolic acidosis. One treatment with IHD is typically sufficient for resolution of acidosis and global improvement clinically. We describe a case of massive APAP overdose presenting with altered mental status and lactic acidosis, refractory to multiple treatments of IHD as well as CRRT and high-dose NAC along with fomepizole. Despite these interventions, fulminant liver failure progressed with cerebral edema, coagulopathy and death. This is the first description of a fatal acetaminophen ingestion refractory to both IHD and prolonged CRRT. This case highlights the need for further investigation in the management of massive APAP overdose, including optimal method and timing of renal replacement therapy.

Continuous Venovenous Hemofiltration as a Rescue Therapy for Severe Acetaminophen Toxicity in a Toddler

Acetaminophen poisoning is one of the common accidental poisoning in children. Accidental administration of mismatched doses of drops for syrups can lead to life-threatening overdose. N-acetylcysteine (NAC) is the specific antidote; however, extracorporeal therapy such as continuous venovenous hemofiltration (CVVH) can be used as a rescue measure when there is no improvement despite adequate NAC therapy and can be lifesaving. We reported an 18-month-old male infant patient who presented with acetaminophen poisoning following accidental ingestion of acetaminophen drops in place of syrup and developed fulminant hepatic failure. Treatment with NAC did not lead to improvement and CVVH was used as a rescue therapy for 24 hours which led to dramatic clinical and biochemical improvement with intact neurological outcome.

Renal replacement therapy in the management of intoxications in children: recommendations from the Pediatric Continuous Renal Replacement Therapy (PCRRT) workgroup

BACKGROUND

Intentional or unintentional ingestions among children and adolescents are common. There are a number of ingestions amenable to renal replacement therapy (RRT).

METHODS

We systematically searched PubMed/Medline, Embase, and Cochrane databases for literature regarding drugs/intoxicants and treatment with RRT in pediatric populations. Two experts from the PCRRT (Pediatric Continuous Renal Replacement Therapy) workgroup assessed titles, abstracts, and full-text articles for extraction of data. The data from the literature search was shared with the PCRRT workgroup and two expert toxicologists, and expert panel recommendations were developed.

RESULTS AND CONCLUSIONS

We have presented the recommendations concerning the use of RRTs for treatment of intoxications with toxic alcohols, lithium, vancomycin, theophylline, barbiturates, metformin, carbamazepine, methotrexate, phenytoin, acetaminophen, salicylates, valproic acid, and aminoglycosides.

A Rare Case of Acetaminophen Toxicity Leading to Severe Kidney Injury

Acetaminophen is one of the most common analgesic medications available over the counter. Acetaminophen overdose can cause both hepatic and renal injuries. The literature suggests the incidence of acute kidney injury is around 2% - 10% in those with acetaminophen overdose. We report a case of acute kidney injury from acetaminophen overdose requiring hemodialysis. 

Haemodiafiltration as an effective treatment option for massive paracetamol overdose

An 84-year-old woman presented to hospital with severe clinical and metabolic sequelaesequelae of a massive paracetamol overdose (concentration=822 mg/L). In spite of N-acetylcysteine therapy, she deteriorated with evidence of mitochondrial dysfunction. Although the EXtracorporeal TReatments In Poisoning group recommend adjunct haemodialysis (HD) in such a context, this was difficult to start due to haemodynamic instability. Instead, a trial of continuous venovenous haemodiafiltration (CVVHDF) was initiated in an attempt to restore normal mitochondrial function, normal pH and to actively remove the offending drug. Fortunately, plasma paracetamol levels fell exponentially over the subsequent 24-48 hours without the need to commence HD. The patient made a full recovery and was later discharged from the hospital. This case highlights that CVVHDF can be a reasonable alternative to HD for managing massive paracetamol overdoses in the context of mitochondrial dysfunction.

A Case Report of Massive Acetaminophen Poisoning Treated with a Novel "Triple Therapy": N-Acetylcysteine, 4-Methylpyrazole, and Hemodialysis

Massive acetaminophen (N-acetyl-p-aminophenol; APAP) ingestion is characterized by a rapid onset of mitochondrial dysfunction, including metabolic acidosis, lactemia, and altered mental status without hepatotoxicity which may not respond to the standard doses of N-acetylcysteine (NAC). A 64-year-old woman without medical history presented comatose after an ingestion of 208 tablets of Tylenol PM™ (APAP 500 mg and diphenhydramine 25 mg). The initial APAP concentration measured 1,017 µg/mL (therapeutic range 10-30 µg/mL), and elevated anion gap metabolic acidosis, lactemia, and 5-oxoprolinemia were detected. High-dose intravenous (IV) NAC, 4-methylpyrazole (4-MP), and hemodialysis (HD) were initiated. She was transferred to a liver transplant center and continued both NAC and HD therapies until complete resolution of metabolic acidosis and coma without developing hepatitis. She was discharged without sequelae. This is the fourth highest APAP concentration recorded in a surviving patient. Moreover, this is the first report of a novel "triple therapy" using NAC, 4-MP, and HD in the setting of massive APAP ingestion that presents with coma, elevated anion gap metabolic acidosis, and lactemia. Emergency physicians should recognize these critically ill patients and consider high-dose NAC, 4-MP, and HD to be initiated in the emergency department (ED).

Pain Management in Pediatric Chronic Kidney Disease

Pain is a common problem in children with chronic kidney disease (CKD); however, limited data exist regarding its management. Although most pain is managed pharmacologically, in some instances non-pharmacologic management can aid in safely ameliorating discomfort. Because of the accumulation of toxic metabolites, many common pain medications have adverse effects on kidney function or altered pharmacokinetics in the setting of CKD. Decreased clearance impacts safe dosing of analgesics. The pain management of patients on renal replacement therapy requires an understanding of drug clearance due to the different modalities of dialysis. This educational review highlights pain medications that are safe, albeit often with adjusted dosing, as well as drugs best avoided in the management of pediatric kidney disease. Acetaminophen should be used as a first-line therapy for pain management in children with CKD. Opioids may be added to control moderate to severe pain. Although data are currently lacking, buprenorphine holds promise as a potentially useful drug for the treatment of pain in pediatric patients with CKD. The addition of adjuvant pain medications and non-pharmacologic therapies maybe also be helpful. Despite these options, pain often remains difficult to treat in children with CKD.

Haemodialysis in acute paracetamol poisoning

A woman aged 23 years presented late with clinical and biochemical features of a life-threatening paracetamol (acetaminophen) overdose. Despite instigating N-acetylcysteine treatment, due to evidence of mitochondrial dysfunction together with an exceedingly high paracetamol level, the decision was made to dialyse the patient acutely to remove the parent drug. This was highly effective, and with on-going supportive care, the patient made a full recovery without the need for transplantation. This case highlights the role of extracorporeal therapy as a treatment option in selected cases of paracetamol overdose, consistent with the international guidelines.