Influence of acetaminophen at therapeutic doses on surrogate markers of severity of acute viral hepatitis

Association between adverse outcomes of hepatitis A and acetaminophen use: A population-based cohort study

BACKGROUND

Acetaminophen (APAP) may cause acute liver injury with therapeutic doses in high-risk conditions such as chronic alcohol consumption or malnutrition. In acute hepatitis A (AHA), however, the safety of APAP has not been fully established. This study examined the potential association between APAP use and clinical outcomes of AHA in a nationwide and hospital-based cohort.

METHODS

Adult patients with AHA were identified from claims data of South Korean national healthcare insurance between 2008 and 2016 (n = 43,500). Logistic regression models were used to compare the risk of adverse outcomes (renal replacement therapy, hepatic encephalopathy and/or brain edema, mechanical ventilation, and liver transplantation) in patients exposed to APAP against control and patients exposed to NSAIDs. A propensity score (PS)-matched hospital-based AHA cohort (n = 146) was assessed for biochemical profiles after exposure to APAP or NSAIDs.

RESULTS

AHA patients were exposed to APAP or NSAIDs in 26.4% and 11.5% of cases, respectively. Compared to NSAID treatment, APAP exposure was associated with a higher incidence of hospitalization (98.8% vs. 92.4%; p < 0.0001). APAP exposure was independently associated with increased adverse outcomes (odds ratio [OR] = 5.66, p < 0.0001 against control; OR =1.67, p = 0.0015 against NSAIDs). PS-matched hospital cohort showed higher peak serum bilirubin levels (7.0 vs. 5.3 mg/dL; p = 0.03) and a longer time to recovery of jaundice after APAP use than with NSAID use.

CONCLUSION

APAP exposure was associated with increased adverse outcomes in a nationwide AHA cohort.

Effect of standard dose paracetamol versus placebo as antipyretic therapy on liver injury in adult dengue infection: a multicentre randomised controlled trial

BACKGROUND

Dengue is a common cause of acute liver failure in tropical countries. Paracetamol is the recommended antipyretic for dengue. Related observational studies in dengue have suggested that excessive paracetamol intake is related to hepatic injury. We aimed to evaluate whether standard dose paracetamol as an antipyretic in dengue infection caused transaminase elevation, and to evaluate the efficacy of paracetamol.

METHODS

In this randomised, double-blind, placebo-controlled trial, adult participants (aged ≥18 years) with dengue, as confirmed by either positive NS1 antigen, positive dengue IgM antigen with thrombocytopenia, or positive PCR test, were enrolled at three Royal Thai Army hospitals in Thailand. Key exclusion criteria were baseline AST or ALT concentrations of more than 3 times the upper limit of normal, cirrhosis, indication of paracetamol other than dengue infection, concurrent diagnosis of other causes of fever, or pregnancy. Patients were randomly assigned (1:1), by a computer-generated block randomisation procedure (block size of six), to receive either paracetamol (500 mg) or placebo (500 mg) every 4 h when body temperature exceeded 38°C during hospitalisation. Participants and investigators were masked to treatment assignment. The primary outcome was the proportion of participants with transaminase elevation, defined as serum aspartate transaminase (AST) and alanine transaminase (ALT) concentrations of more than 3 times the upper limit of normal on recovery day, in the intention-to-treat population. Prespecified interim analyses for safety and efficacy were performed with group sequential stopping boundaries. This trial is registered with ClinicalTrials.gov, number NCT02833584.

FINDINGS

Between Sept 1, 2016, and Dec 12, 2017, 125 participants were randomly assigned to receive either paracetamol (n=63) or placebo (n=62). 123 participants were included in the intention-to-treat population. The median daily dose of study medication was 1·5 g (IQR 0·8-2·0). The study was terminated early owing to a higher rate of transaminase elevation in the paracetamol group than in the placebo group (22% vs 10%; incidence rate ratio 3·77, 95% CI 1·36-10·46, p=0·011). The change of AST and ALT concentrations in the paracetamol group was higher than in the placebo group (mean difference 12·43 U/L per day, 7·16-17·71, p<0·0001 for AST; 7·40 U/L per day, 95% CI 3·68-11·13, p=0·0001 for ALT). Three participants in the paracetamol group had severe dengue: two had upper gastric haemorrhage and one had acute kidney injury. No patients died or had liver failure.

INTERPRETATION

Use of standard dose paracetamol in dengue infection increased the incidence of transaminase elevation, and also overall transaminase concentrations in the absence of a counterbalancing reduced fever or pain score.

FUNDING

Phramongkutklao College of Medicine.

[Prescription of acetaminophen in five French hospitals: What are the practices?]

AIM

Acetaminophen is widely used in hospital settings and often considered as nontoxic. We conducted a multicentric study in order to evaluate its proper use.

METHOD

Prescriptions from five general hospitals were analyzed, according to dose adjustments required in renal or liver failure, weight or chronic alcoholism, determined using a literature review. Other criteria have been assessed: indication for parenteral access, accuracy of administration time and pain assessment.

RESULTS

Among the 1256 analyzed prescriptions, 21% are non-compliants. The main causes of non-compliance (NC) are adjustments to weight and renal failure. Higher NC rates concern chronic alcoholism and liver failure.

CONCLUSION

Misuse of acetaminophen seems related to a lack of official recommendations concerning dose adjustments. Hospital pharmacists have an important role to play in the promotion of proper use of acetaminophen. Therefore we established a prescribing aid.

Can paracetamol (acetaminophen) be administered to patients with liver impairment?

Although 60 years have passed since it became widely available on the therapeutic market, paracetamol dosage in patients with liver disease remains a controversial subject. Fulminant hepatic failure has been a well documented consequence of paracetamol overdose since its introduction, while short and long term use have both been associated with elevation of liver transaminases, a surrogate marker for acute liver injury. From these reports it has been assumed that paracetamol use should be restricted or the dosage reduced in patients with chronic liver disease. We review the factors that have been purported to increase risk of hepatocellular injury from paracetamol and the pharmacokinetic alterations in different pathologies of chronic liver disease which may affect this risk. We postulate that inadvertent under-dosing may result in concentrations too low to enable efficacy. Specific research to improve the evidence base for prescribing paracetamol in patients with different aetiologies of chronic liver disease is needed.

Fatal fulminant hepatitis E associated with autoimmune hepatitis and excessive paracetamol intake in Southeastern France

We present, to our knowledge, the first case of fatal fulminant liver failure associated with hepatitis E virus infection, autoimmune hepatitis, and excessive paracetamol intake, which occurred in a 77-year-old woman. Hepatitis E testing should be performed in severe acute liver failure cases, even when another cause has been identified.

Outcomes of patients with acetaminophen-associated toxic hepatitis at a far east poison center

BACKGROUND

There is an overall paucity of data regarding the outcomes of patients with acetaminophen-associated toxic hepatitis in Taiwan. Therefore, the purpose of this study was to recruit a larger number of patients and to examine the clinical features, the degrees of toxic hepatitis, the physiological markers, and the clinical outcomes after intentional acetaminophen poisoning, and to determine what association, if any, might exist between these findings.

METHODS

We examined the medical records of 187 patients with intentional acetaminophen poisoning who were examined at Chang Gung Memorial Hospital between 2000 and 2011. Patients were categorized into 2 groups according to hepatic complications, i.e. with (n = 15) or without (n = 172) toxic hepatitis. Demographic, clinical, and laboratory data were collected, and the mortality rate was analyzed.

RESULTS

It was found that patients with toxic hepatitis had higher serum acetaminophen level (P = 0.007), but they also arrived to the hospital later (P < 0.001) than patients without toxic hepatitis. Furthermore, patients with toxic hepatitis showed higher incidences of acute respiratory failure (P = 0.012) than those shown by patients who did not have hepatitis. The laboratory examinations also revealed greater degrees of granulocytosis (P < 0.001) and poorer liver function tests (P < 0.001) in patients with hepatitis than in patients without hepatitis. Nevertheless, a univariate logistic regression model failed to identify any significant risk factors for toxic hepatitis complication after ingestion (P > 0.05). At the end of the analysis, 1 patient with toxic hepatitis died of liver failure. Finally, there was no significant difference in mortality between patients with and without hepatitis (P = 0.080).

CONCLUSION

The analytical data revealed that toxic hepatitis was not uncommon (15/187 or 8.0%) after acetaminophen overdose. Further studies are warranted.

Acute liver failure

Untreated acute liver failure (ALF) has a poor outcome and so rapid diagnosis and management is vital if the patient is to survive. ALF has such profound and widespread physiological consequences that whenever possible, patients with ALF should be managed in an intensive care unit. Management is to support the physiology and treat the underlying cause. Advice should be sought from a centre capable of performing liver transplantation. Should recovery seem unlikely, liver transplantation is a viable treatment option in some cases.

Lessons from look-back in acute liver failure? A single centre experience of 3300 patients

BACKGROUND & AIMS

Acute liver failure (ALF) is a rapidly progressive critical illness with high mortality. Complex intensive care unit (ICU) protocols and emergency liver transplantation (ELT) are now often available, but rarity and severity of illness have limited its study and evidence-base for care. We reviewed patients treated over a 35-year period at a specialist high-volume ICU, quantifying changes in disease aetiology, severity and evolution of ICU support and ELT use and outcome.

METHODS

Review of adult patients admitted during the period 1973-2008, with acute liver dysfunction and coagulopathy with overt hepatic encephalopathy (ALF) and those without (acute liver injury; ALI).

RESULTS

3305 patients fulfilled inclusion criteria, 2095 with ALF. Overall hospital survival increased from 30% in 1973-78 to 76% in 2004-08; in ALF from 17% to 62% (both p<0.0001). In ALF patients treated without ELT, survival rose from 17% to 48% (p<0.0001); in those undergoing ELT (n=387) from 56% in 1984-88 to 86% in 2004-08 (p<0.01). Coincident with drug sales-restriction, paracetamol-related admissions fell significantly. Viral admissions fell from 56% to 17% of non-paracetamol cases (p<0.0001). Admission markers of liver injury severity fell significantly and the proportion of patients with intracranial hypertension (ICH) fell from 76% in 1984-88 to 20% in 2004-08 (p<0.0001). In those with ICH, mortality fell from 95% to 55% (p<0.0001).

CONCLUSIONS

The nature and outcome of ALF have transformed over 35 years, with major improvements in survival and a fall in prevalence of cerebral oedema and ICH, likely consequent upon earlier illness recognition, improved ICU care, and use of ELT.

Acetaminophen-induced acute liver injury in HCV transgenic mice

The exact etiology of clinical cases of acute liver failure is difficult to ascertain and it is likely that various co-morbidity factors play a role. For example, epidemiological evidence suggests that coexistent hepatitis C virus (HCV) infection increased the risk of acetaminophen-induced acute liver injury, and was associated with an increased risk of progression to acute liver failure. However, little is known about possible mechanisms of enhanced acetaminophen hepatotoxicity in HCV-infected subjects. In this study, we tested a hypothesis that HCV-Tg mice may be more susceptible to acetaminophen hepatotoxicity, and also evaluated the mechanisms of acetaminophen-induced liver damage in wild type and HCV-Tg mice expressing core, E1 and E2 proteins. Male mice were treated with a single dose of acetaminophen (300 or 500 mg/kg in fed animals; or 200 mg/kg in fasted animals; i.g.) and liver and serum endpoints were evaluated at 4 and 24h after dosing. Our results suggest that in fed mice, liver toxicity in HCV-Tg mice is not markedly exaggerated as compared to the wild-type mice. In fasted mice, greater liver injury was observed in HCV-Tg mice. In fed mice dosed with 300 mg/kg acetaminophen, we observed that liver mitochondria in HCV-Tg mice exhibited signs of dysfunction showing the potential mechanism for increased susceptibility.

Epidemiology of liver failure

The etiology of fulminant hepatitis varies in different countries and at different times. The main causes of fulminant hepatitis are viruses, paracetamol, drugs (other than paracetamol), poisons and 15-30% remained of undetermined origin. The prevalence of these etiologies varies according to the geographic region and has changed over the past 10 years. Paracetamol has now overtaken viruses (particularly hepatitis B virus) as the leading cause of fulminant hepatitis. Establishing the cause of fulminant hepatitis is an important step in the management of acute liver failure, so that specific therapy can be initiated and any contraindications to liver transplantation be eliminated.

Central role of mitochondria in drug-induced liver injury

A frequent mechanism for drug-induced liver injury (DILI) is the formation of reactive metabolites that trigger hepatitis through direct toxicity or immune reactions. Both events cause mitochondrial membrane disruption. Genetic or acquired factors predispose to metabolite-mediated hepatitis by increasing the formation of the reactive metabolite, decreasing its detoxification, or by the presence of critical human leukocyte antigen molecule(s). In other instances, the parent drug itself triggers mitochondrial membrane disruption or inhibits mitochondrial function through different mechanisms. Drugs can sequester coenzyme A or can inhibit mitochondrial β-oxidation enzymes, the transfer of electrons along the respiratory chain, or adenosine triphosphate (ATP) synthase. Drugs can also destroy mitochondrial DNA, inhibit its replication, decrease mitochondrial transcripts, or hamper mitochondrial protein synthesis. Quite often, a single drug has many different effects on mitochondrial function. A severe impairment of oxidative phosphorylation decreases hepatic ATP, leading to cell dysfunction or necrosis; it can also secondarily inhibit ß-oxidation, thus causing steatosis, and can also inhibit pyruvate catabolism, leading to lactic acidosis. A severe impairment of β-oxidation can cause a fatty liver; further, decreased gluconeogenesis and increased utilization of glucose to compensate for the inability to oxidize fatty acids, together with the mitochondrial toxicity of accumulated free fatty acids and lipid peroxidation products, may impair energy production, possibly leading to coma and death. Susceptibility to parent drug-mediated mitochondrial dysfunction can be increased by factors impairing the removal of the toxic parent compound or by the presence of other medical condition(s) impairing mitochondrial function. New drug molecules should be screened for possible mitochondrial effects.

Acute liver failure

Acute liver failure is a rare disorder with high mortality and resource cost. In the developing world, viral causes predominate, with hepatitis E infection recognised as a common cause in many countries. In the USA and much of western Europe, the incidence of virally induced disease has declined substantially in the past few years, with most cases now arising from drug-induced liver injury, often from paracetamol. However, a large proportion of cases are of unknown origin. Acute liver failure can be associated with rapidly progressive multiorgan failure and devastating complications; however, outcomes have been improved by use of emergency liver transplantation. An evidence base for practice is emerging for supportive care, and a better understanding of the pathophysiology of the disorder, especially in relation to hepatic encephalopathy, will probably soon lead to further improvements in survival rates.

Bacterial- and viral-induced inflammation increases sensitivity to acetaminophen hepatotoxicity

Acetaminophen (APAP)-induced hepatotoxicity accounts for nearly half of acute liver failure cases in the United States. The doses that produce hepatotoxicity vary considerably and many risk factors have been proposed, including liver inflammation from viral hepatitis. Interestingly, inflammatory stress from another stimulus, bacterial endotoxin (lipopolysaccharide, LPS), renders the liver more sensitive to hepatotoxicity from numerous xenobiotic agents. The purpose of these studies was to test the hypothesis that inflammation induced by LPS or infection with reovirus increases sensitivity to APAP-induced liver injury. For LPS-induced inflammation, C57BL/6J mice were treated with either saline or LPS (44 x 10(6) EU/kg, ip) 2 h before treatment with APAP (100-400 mg/kg, ip) or saline. No elevation in serum alanine aminotransferase (ALT) activity was observed in mice that received vehicle or LPS alone. LPS co-treatment produced a leftward shift of the dose-response curve for APAP-induced hepatotoxicity and led to significantly greater tumor necrosis factor-alpha (TNF) production than APAP alone. Reovirus serotype 1 (10(8) PFU, iv) induced inflammation in Balb/c mice as evidenced by increases in hepatic mRNAs for macrophage inhibitory protein-2, interleukin-6, and TNF. Co-administration of reovirus and APAP at doses of 450 and 700 mg/kg (2 h after reovirus) led to increases in serum ALT activity, whereas neither reovirus nor APAP alone produced liver injury. Consistent with the increases in serum ALT activity, histopathologic examination revealed centrilobular necrosis with marked neutrophilic accumulation only in livers of mice treated with LPS/APAP or with reovirus/APAP. The results suggest that normally noninjurious doses of APAP are rendered hepatotoxic by modest inflammation, whether bacterial or viral in origin.

Susceptibility to acetaminophen (APAP) toxicity unexpectedly is decreased during acute viral hepatitis in mice

Acetaminophen (APAP) hepatotoxicity results from cytochrome P450 metabolism of APAP to the toxic metabolite, n-acetyl-benzoquinone imine (NAPQI), which reacts with cysteinyl residues to form APAP adducts and initiates cell injury. As APAP is commonly used during viral illnesses there has been concern that APAP injury may be additive to that of viral hepatitis, leading physicians to advise against its use in such patients; this has not been investigated experimentally. We infected C57BL/6 male mice with replication-deficient adenovirus to produce moderately severe acute viral hepatitis and observed that APAP doses that were hepatotoxic or lethal in control mice produced neither death nor additional increase in serum ALT when administered to infected mice at the peak of virus-induced liver injury. Moreover, the concentration of hepatic APAP-protein adducts formed in these mice was only 10% that in control mice. Protection from APAP hepatotoxicity also was observed earlier in the course of infection, prior to the peak virus-induced ALT rise. Hepatic glutathione limits APAP-protein adduct formation but glutathione levels were similar in control and infected mice. Cyp1a2 (E.C. 1.14.14.1) and Cyp2e1 (E.C. 1.14.13.n7) mRNA expression decreased by 3 days post-infection and hepatic Cyp2e1 protein levels were reduced almost 90% at 7 days, when adduct formation was maximally inhibited. In vitro, hepatocytes from virally infected mice also were resistant to APAP-induced injury but sensitive to NAPQI. Rather than potentiating APAP-induced liver injury, acute viral hepatitis in this model resulted in selective down-regulation of APAP metabolizing P450s in liver and decreased the risk of APAP hepatotoxicity.

Intrinsic versus idiosyncratic drug-induced hepatotoxicity--two villains or one?

"Intrinsic" and "idiosyncratic" drug-induced liver injury reactions are commonly thought to arise by different modes of action. Intrinsic toxicity is reproducible in animals and occurs dose-dependently at sublethal doses. Environmental and genetic sensitivity factors can influence the toxicity of intrinsic hepatotoxicants. Among these is inflammatory stress. For example, exposure of mice to inflammatory bacterial lipopolysaccharide (LPS) causes a leftward shift in the dose-response relationship for acetaminophen hepatotoxicity; that is, acetaminophen toxicity is enhanced by LPS-induced inflammatory stress. Idiosyncratic reactions present themselves very differently than intrinsic ones; they happen in a minority of patients, with variable time of onset and no obvious relationship to drug dose, and they are not reproducible in usual animal tests. Although these characteristics seem to distinguish them from intrinsic reactions, consideration of fundamental principles of dose response can explain the differences. For a drug that causes idiosyncratic hepatotoxicity, the liver may not be a typical target for toxicity because the dose-response curve for hepatotoxicity lies to the right of the lethal dose. However, a sporadically occurring sensitivity factor, such as an inflammatory episode, could shift the dose-response curve for hepatotoxicity to the left, thereby bringing hepatotoxic doses into the therapeutic range. This hypothesis can account for the bizarre characteristics of idiosyncratic reactions and is supported by recent results showing that several drugs associated with human idiosyncratic reactions can be rendered hepatotoxic to rodents upon interaction with an inflammatory stimulus. In light of this view, intrinsic and idiosyncratic reactions may not be that different after all.

Update on the use of analgesics versus nonsteroidal anti-inflammatory drugs in rheumatic disorders: risks and benefits

PURPOSE OF REVIEW

In the last 2 years, there have been numerous publications on the safety of nonsteroidal anti-inflammatory drugs and cyclo-oxygenase-2 inhibitors. An evaluation of the potential risks and benefits of other analgesics has also followed. In this time of greater analysis of analgesic use, this review seeks to present the most recent evidence.

RECENT FINDINGS

Concerns of potential hepatotoxicity of therapeutic doses of paracetamol have been highlighted in the last 18 months. The efficacy and risks of long-term opioid use have also been reevaluated. The debate over nonsteroidal anti-inflammatory drug and cyclo-oxygenase-2 inhibitor safety continues.

SUMMARY

Recent evidence has prompted a reassessment of the safety of paracetamol in certain groups of patients. Further clarification on the risks of nonsteroidal anti-inflammatory drug and cyclo-oxygenase-2 therapy for individuals is covered. Their use, increased cardiovascular risk and long-term implications need to be evaluated.