Acetaminophen hepatotoxicity and acute liver failure

Internet survey of home storage of paracetamol by individuals in the UK

AIM

Paracetamol (acetaminophen) is a common cause of liver failure due to overdose. Legislation introduced in the UK in 1998 to limit pack sizes of paracetamol has had limited impact on the overall number and severity of paracetamol overdoses. This may be because people have large amounts of paracetamol stored at home, but no previous studies have explored this question.

METHODS

Individuals who regularly take part in market research surveys were invited to take part in an Internet survey. They were asked to supply demographic details, the frequency with which they use paracetamol and ibuprofen, and details of the amount and location of these drugs that they possessed.

RESULTS

The mean age of respondents was 43.3 years (standard deviation 14.5 years), and 49.9% were female. People with both ibuprofen and paracetamol tended to have more packs and tablets of paracetamol (P < 0.001) and over a third had 32 or more paracetamol tablets. The most common pack size was 16 tablet packs (44.8% of all packs), which accounted for 39.4% of tablets. The most common site of paracetamol storage in the home was the kitchen (63.8% of people, 95% confidence interval 60.7, 66.7).

CONCLUSION

This study suggests that pack size legislation in the UK has had limited effect on the amount of paracetamol that individuals have access to in the home. This may explain, at least in part, the limited impact of the pack size legislation on paracetamol overdoses in the UK.

Maintenance of mitochondrial genomic integrity in the absence of manganese superoxide dismutase in mouse liver hepatocytes

Manganese superoxide dismutase, encoded by the Sod2 gene, is a ubiquitously expressed mitochondrial antioxidant enzyme that is essential for mammalian life. Mice born with constitutive genetic knockout of Sod2 do not survive the neonatal stage, which renders the longitudinal study of the biochemical and metabolic effects of Sod2 loss difficult. However, multiple studies have demonstrated that tissue-specific knockout of Sod2 in murine liver yields no observable gross pathology or injury to the mouse. We hypothesized that Sod2 loss may have sub-pathologic effects on liver biology, including the acquisition of reactive oxygen species-mediated mitochondrial DNA mutations. To evaluate this, we established and verified a hepatocyte-specific knockout of Sod2 in C57/B6 mice using Cre-LoxP recombination technology. We utilized deep sequencing to identify possible mutations in Sod2^−/− mitochondrial DNA as compared to wt, and both RT-PCR and traditional biochemical assays to evaluate baseline differences in redox-sensitive pathways in Sod2^−/− hepatocytes. Surprisingly, no mutations in Sod2^−/− mitochondrial DNA were detected despite measurable increases in dihydroethidium staining in situ and concomitant decreases in complex II activity indicative of elevated superoxide in the Sod2^−/− hepatocytes. In contrast, numerous compensatory alterations in gene expression were identified that suggest hepatocytes have a remarkable capacity to adapt and overcome the loss of Sod2 through transcriptional means. Taken together, these results suggest that murine hepatocytes have a large reserve capacity to cope with the presence of additional mitochondrial reactive oxygen species.

DILI: New Insights into Diagnosis and Management

Drug-induced liver injury continues to have a significant impact. With over 1000 drugs now registered as causing DILI, this form of liver injury is the most cited reason for withdrawal of a drug from the marketplace. Despite this, the diagnosis of DILI continues to rely on subjective measures and expert opinion with results that are both difficult to verify and reproduce. However, recent developments in DILI research may provide new insights to improve diagnosis and treatment in the future.

Genistein protection against acetaminophen-induced liver injury via its potential impact on the activation of UDP-glucuronosyltransferase and antioxidant enzymes

The purpose of this study was to investigate genistein's influence on the relationship between the activation of uridine diphosphate glucuronosyltransferase (UGTs) and the protection against acetaminophen-induced liver toxicity. Animal experimental results revealed that genistein (50, 100 or 200mg/BWkg) significantly ameliorated the biomarkers alanine aminotransferase, alanine aminotransferase, lactate dehydrogenase and malondialdehyde, as indicators of acute liver damage caused by APAP (200mg/BWkg). The level of GSH declined sharply after treatment with APAP within 1h in both the liver and blood with and without genistein. However, after 16h, the levels approached or returned to the original level. Genistein may accelerate and promote APAP glucuronidation as the results showed that APAP-glucuronide increased by 18.44%, 46.79%, and 66.49% for 4h of treatment with genistein dosages of 50, 100 or 200mg/BWkg, respectively, compared with the APAP-only treatment. The activation of UGTs and glutathione peroxidase and the inhibition of CYP2E1 by genistein were observed, and UGTs mRNA expression level with genistein was measured. These findings suggest that genistein can prevent and protect against APAP-induced liver toxicity due to the inhibition of APAP biotransformation and the resistance to oxidative stress via the modulation of the activities of metabolism and the antioxidant enzyme.

Prenatal tolerability of acetaminophen and other over-the-counter non-selective cyclooxygenase inhibitors

Over-the-counter cyclooxygenase inhibitors are used to relief fever and various types of acute pain like headache, toothache, earache, sore throat, as well as postoperative and menstrual ones. They are also major ingredients in cold and flu mixtures. Unlike well-known organ toxicological profile, their prenatal toxicity was not fully established. For a long time, acetaminophen was considered as a relatively safe antipyretic and analgesic drug during pregnancy. However, a new data indicate that it may increase the risk of cryptorchidism and asthma during childhood as well as preeclampsia, preterm birth, maternal phlebothrombosis and pulmonary embolism. Contrary to acetaminophen, non-selective cyclooxygenase inhibitors (non-steroidal anti-inflammatory drugs - NSAID; i.e., diclofenac, ibuprofen, naproxen) may induce intrauterine growth retardation, ductus arteriosus constriction with secondary persistent pulmonary hypertension, reduced fetal renal perfusion that led to oligohydramion, prolonged pregnancy as well as increase prevalence of intracranial bleeding in newborns. Furthermore, a higher risk of miscarriage, stillbirth and some congenital malformations (cardiac and diaphragmatic defects, celosomy - gastroschisis and umbilical hernia) was reported for non-selective inhibitors, in particular high doses of acetylsalicylic acid (aspirin).

Prevalence and correlates for nonmedical use of prescription opioids among urban and rural residents

BACKGROUND

In the United States, rural areas have reported an increase in overdose deaths secondary to nonmedical use of prescription opioids. Little is known about the differences in nonmedical use of prescription opioids among urban and rural adults.

METHODS

Using the 2008-2009 National Survey on Drug Use and Health, we examined the prevalence of nonmedical use of prescription opioids in urban and rural counties and determined bivariate and multivariate associations, stratified by county. We also compared type of opioids, stratified by county.

RESULTS

Among 75,964 respondents, the prevalence of nonmedical use of prescriptions opioids was similar among residents in urban and rural counties (4.7% vs. 4.3%, p=0.15). Urban and rural residents with severe psychological distress and nonmedical use of other prescription medications were more likely to report nonmedical use of opioids. Urban residents whose first use of illicit drugs was between the age of 18 and 25 and who reported alcohol use were more likely to report nonmedical use. Black and Hispanic urban residents were less likely to use prescription opioids nonmedically compared to white urban residents. Rural residents were more likely than urban residents to use acetaminophen with propoxyphene (61.1% vs. 55.8%, p=0.02), methadone (14.8% vs. 9.1%, p=0.003) and acetaminophen with codeine (3.5% vs. 1.9%, p=0.05).

CONCLUSIONS

Prevalence and risk factors related to nonmedical use of opioids are similar between urban and rural residents; however rural residents report propoxyphene, codeine, and methadone use more than their urban counterparts. Prevention and treatment interventions may need to be tailored for specific communities.

High-mobility group box 1 (HMGB1)-Toll-like receptor (TLR)4-interleukin (IL)-23-IL-17A axis in drug-induced damage-associated lethal hepatitis: Interaction of γδ T cells with macrophages

Acetaminophen overdose causes acute liver inflammation with neutrophil infiltration; however, the mechanism of damage-associated inflammation has not been elucidated. In this study we found that the HMGB1-TLR4-IL-23-IL-17A axis played a crucial role in acetaminophen-induced infiltration of neutrophils and liver injury. Notably, interleukin (IL)-17A and IL-23 significantly increased after acetaminophen challenge. A neutralizing antibody against IL-17A attenuated the recruitment of neutrophils, accompanied by reduced liver injury. Only IL-17A(+) CD3(+) γδ T cell receptor (TCR)(+) cells were significantly increased in the liver, and depletion of γδ T cells, but not CD4(+) T cells or natural killer (NK)T cells significantly reduced IL-17A production, attenuated liver injury, and decreased the number of neutrophils in the liver. Furthermore, a neutralizing IL-23 p19 antibody or p40-deficiency significantly decreased the levels of IL-17A and infiltration of neutrophils. After in vitro stimulation, the percentage of IL-17A-producing γδ T cells and the levels of supernatant IL-17A from total hepatic lymphocytes or purified γδ T cells markedly increased in the presence with IL-23. Importantly, IL-23 and IL-17A were reduced after inhibition of macrophages and could not be induced in Toll-like receptor TLR4(-/-) mice after acetaminophen challenge. Meanwhile, serum high-mobility group box 1 (HMGB1), a damage-associated molecule released from necrotic hepatocytes, increased after acetaminophen challenge, and the HMGB1 inhibitor glycyrrhizin markedly reduced the production of IL-23 and IL-17A and the recruitment of hepatic neutrophils. HMGB1 stimulated the production of IL-23 by TLR4(+/+) but not by TLR4(-/-) macrophages.

CONCLUSION

The HMGB1-TLR4-IL-23 pathway in macrophages makes the generation of IL-17-producing γδ T cells, which mediates neutrophil infiltration and damage-induced liver inflammation.

A review of pharmacotherapy for chronic low back pain with considerations for sports medicine

Up to 30% of athletes experience low back pain (LBP) depending on sport type, sex, training intensity and frequency, and technique. United States clinical guidelines define back pain as chronic if it persists for ≥ 12 weeks, and subacute if it persists 4 to < 12 weeks. Certain sports injuries are likely to lead to chronic pain. Persistent or chronic symptoms are frequently associated with degenerative lumbar disc disease or spondylolytic stress lesions. Exercise therapy is widely used and is the most conservative form of treatment for chronic LBP (cLBP). Pharmacotherapies for cLBP include acetaminophen, nonsteroidal anti-inflammatory drugs, and opioids. Acetaminophen is a well-tolerated first-line pharmacotherapy, but high-dose, long-term use is associated with hepatic toxicity. Nonsteroidal anti-inflammatory drugs can be an effective second-line option if acetaminophen proves inadequate but they have well-known risks of gastrointestinal, cardiovascular, and other systemic adverse effects that increase with patient age, dose amount, and duration of use. The serotonin-norepinephrine reuptake inhibitor, duloxetine, has demonstrated modest efficacy and is associated with systematic adverse events, including serotonin syndrome, which can be dose related or result from interaction with other analgesics. Opioids may be an effective choice for moderate to severe pain but also have significant risks of adverse events and carry a substantial risk of addiction and abuse. Because the course of cLBP may be protracted, patients may require treatment over years or decades, and it is critical that the risk/benefit profiles of pharmacotherapies are closely evaluated to ensure that short- and long-term treatments are optimized for each patient. This article reviews the clinical evidence and the guideline recommendations for pharmacotherapy of cLBP.

Systematic review of ophthalmate as a novel biomarker of hepatic glutathione depletion

BACKGROUND

Sustainability of hepatic glutathione (GSH) homeostasis is an important cellular defense against oxidative stress. Therefore, knowledge of liver GSH status is important. However, measurement of plasma GSH and tissue is difficult due to its instability. Alternatively, ophthalmate (OPH), an endogenous tripeptide analog of GSH, has been suggested as a potential indicator to assess GSH depletion.

AIM

To provide an overview of present knowledge with respect to the usefulness of OPH as a biomarker for oxidative stress and hepatic GSH homeostasis.

METHODS

A systematic, computerized search combined with a cross-reference search of the literature described in PubMed (January 1975 to January 2012) was conducted, key words: 'ophthalmate' and 'ophthalmic acid'.

RESULTS

Twenty-two articles were included. Hepatic OPH levels increase inversely proportional to a drop in hepatic GSH in mice with paracetamol (PCM) induced hepatotoxicity. Little is known about the stability of OPH in human plasma. To measure the very low physiological concentrations of plasma OPH, liquid chromatography-mass spectrometry techniques can be employed. OPH synthesis can be measured in humans, using stable isotope labeling with a deuterated water ((2)H2O) load.

CONCLUSION

OPH may be a promising biomarker to indicate hepatic glutathione depletion, but the suggested biological pathways need further unraveling.

A one-year observational study of all hospitalized and fatal acute poisonings in Oslo: epidemiology, intention and follow-up

Background

Up to date information on poisoning trends is important. This study reports the epidemiology of all hospitalized acute poisonings in Oslo, including mortality, follow-up referrals, and whether the introduction of over-the-counter sales of paracetamol outside pharmacies had an impact on the frequency of poisonings.

Methods

All acute poisonings of adults (≥16 years) treated at the five hospitals in Oslo from April 2008 to April 2009 were included consecutively in an observational cross-sectional multicentre study. A standardized form was completed by the treating physician, which covered the study aims. All deaths by poisoning in and outside hospitals were registered at the Institute of Forensic Medicine.

Results

There were 1065 hospital admissions of 912 individuals; 460 (50%) were male, and the median age was 36 years. The annual incidence was 2.0 per 1000. The most frequent toxic agents were ethanol (18%), benzodiazepines (15%), paracetamol (11%), and opioids (11%). Physicians classified 46% as possible or definite suicide attempts, 37% as accidental overdoses with substances of abuse (AOSA), and 16% as other accidents. Twenty-four per cent were discharged without any follow-up and the no follow-up odds were highest for AOSA. There were 117 deaths (eight in hospital), of which 75% were males, and the median age was 41 years. Thus, the annual mortality rate was 25 per 100 000 and the in-hospital mortality was 0.8%. Opioids were the most frequent cause of death.

Conclusions

The incidence of hospitalized acute poisonings in Oslo was similar to that in 2003 and there was an equal sex distribution. Compared with a study performed in Oslo in 2003, there has been an increase in poisonings with a suicidal intention. The in-hospital mortality was low and nine out of ten deaths occurred outside hospitals. Opioids were the leading cause of death, so preventive measures should be encouraged among substance abusers. The number of poisonings caused by paracetamol remained unchanged after the introduction of over-the-counter sales outside pharmacies and there were no deaths, so over-the-counter sales may be considered safe.

A survey of adult awareness and use of medicine containing acetaminophen

PURPOSE

To compare awareness, use of acetaminophen, and preferences for receiving information aimed at reducing acetaminophen overdose.

METHODS

A survey of health plan enrollees identified from automated pharmacy data who were long-term and acute users of opioids with acetaminophen (n = 720 each cohort), and a general population cohort (n = 360) during the 2010-2011 cold/flu season. A 74% response rate was achieved. Differences were tested across the three cohorts, and by level of education, using age-adjusted regression models.

RESULTS

Use of over-the-counter or prescription medicine containing acetaminophen in the prior 2 weeks was reported by 84% in the long-term opioid cohort, 76% in the acute opioid cohort, and 36% in the general population, but use of over-the-counter medicine with acetaminophen did not differ across the cohorts (30-34%). All three cohorts were unlikely to correctly identify drugs containing acetaminophen, but the opioid cohorts performed slightly better than the general population. Those with higher education performed slightly better when asked to identify acetaminophen products than those with no college education. The average usual daily acetaminophen dose (mg/day) reported was highest in the long-term opioid cohort (1185), followed by the acute opioid cohort (1010), and the general population (891)-p < 0.001. Estimated supratherapeutic exposure (>4000 mg/day) was rare but three to five times more common in the opioid cohorts than in the general population.

CONCLUSIONS

Acetaminophen use is common, and supratherapeutic exposure may be of concern in users of opioids. Knowledge of which drugs contain acetaminophen appears inadequate; better labeling and proactive education from professionals may be impactful.

Mathematical modeling of liver injury and dysfunction after acetaminophen overdose: early discrimination between survival and death

Acetaminophen (APAP) is the leading cause of acute liver injury in the developed world. Timely administration of N-acetylcysteine (N-Ac) prevents the progression of serious liver injury and disease, whereas failure to administer N-Ac within a critical time frame allows disease progression and in the most severe cases may result in liver failure or death. In this situation, liver transplantation may be the only life-saving measure. Thus, the outcome of an APAP overdose depends on the size of the overdose and the time to first administration of N-Ac. We developed a system of differential equations to describe acute liver injury due to APAP overdose. The Model for Acetaminophen-induced Liver Damage (MALD) uses a patient's aspartate aminotransferase (AST), alanine aminotransferase (ALT), and international normalized ratio (INR) measurements on admission to estimate overdose amount, time elapsed since overdose, and outcome. The mathematical model was then tested on 53 patients from the University of Utah. With the addition of serum creatinine, eventual death was predicted with 100% sensitivity, 91% specificity, 67% positive predictive value (PPV), and 100% negative predictive value (NPV) in this retrospective study. Using only initial AST, ALT, and INR measurements, the model accurately predicted subsequent laboratory values for the majority of individual patients. This is the first dynamical rather than statistical approach to determine poor prognosis in patients with life-threatening liver disease due to APAP overdose.

CONCLUSION

MALD provides a method to estimate overdose amount, time elapsed since overdose, and outcome from patient laboratory values commonly available on admission in cases of acute liver failure due to APAP overdose and should be validated in multicenter prospective evaluation.

Duloxetine in the management of chronic musculoskeletal pain

Chronic musculoskeletal pain is among the most frequent painful complaints that healthcare providers address. The bulk of these complaints are chronic low back pain and chronic osteoarthritis. Osteoarthritis is the most common form of arthritis in the United States. It is a chronic degenerative disorder characterized by a loss of cartilage, and occurs most often in older persons. The management of osteoarthritis and chronic low back pain may involve both nonpharmacologic (eg, weight loss, resistive and aerobic exercise, patient education, cognitive behavioral therapy) and pharmacologic approaches. Older adults with severe osteoarthritis pain are more likely to take analgesics than those with less severe pain. The pharmacologic approaches to painful osteoarthritis remain controversial, but may include topical as well as oral nonsteroidal antiinflammatory drugs, acetaminophen, duloxetine, and opioids. The role of duloxetine for musculoskeletal conditions is still evolving.

TNF-α genetic polymorphism -308G/A and antituberculosis drug-induced hepatitis

BACKGROUND

While the mechanisms underlying the development of drug-induced liver injury are not clear, there is evidence to suggest that tumor necrosis factor-α (TNF-α) plays an important role in drug- or drug metabolite-induced immune responses. We hypothesized that polymorphisms in the TNF-α gene are associated with anti-tuberculosis drug (ATD)-induced hepatitis.

METHODS

Patients who suffered from ATD-induced hepatitis were enrolled in the study. ATD-induced hepatitis was defined as an increase in liver transaminase levels that were more than three times the upper limit of normal. ATD-tolerant patients were used as a control. Patients were treated with first line ATD therapies including isoniazid, rifampicin, ethambutol, and pyrazinamide. We compared the genotype frequencies of the TNF-α polymorphism -308G/A in 77 patients with ATD-induced hepatitis and 229 ATD-tolerant patients.

RESULTS

The frequency of carrying the variant allele (AG or AA) was significantly higher in patients with ATD-induced hepatitis compared with ATD-tolerant patients [26.0% vs. 15.3%, P = 0.034, OR (95% CI) = 1.94 (1.04–3.64)] and the frequency of the A allele was significantly different between the two groups [0.143 vs. 0.079, P = 0.018, OR (95% CI) = 1.95 (1.11–3.44)].

CONCLUSION

These results reveal that the TNF-α genetic polymorphism -308G/A is significantly associated with ATD-induced hepatitis. This genetic variant may be a risk factor for ATD-induced hepatitis in individuals from Korea.

Simple reversed-phase HPLC method with spectrophotometric detection for measuring acetaminophen-protein adducts in rat liver samples

A simple reversed-phase HPLC method for measuring hepatic levels of acetaminophen- (APAP-) protein adduct following an overdose of APAP was developed. An aliquot of liver homogenate in phosphate-buffered saline pH 7.4 (PBS) was placed on a Nanosep centrifugal device, which was centrifuged to obtain a protein residue. This residue was incubated with a solution of p-aminobenzoic acid (PABA), the internal standard, and bacterial protease in PBS, transferred to a Nanosep centrifugal device, and centrifuged. A 100 μL portion of the filtrate was analyzed on a YMC-Pack ODS-AMQ C18 column, using 100 mM potassium dihydrogen phosphate-methanol-acetic acid (100 : 0.6 : 0.1) as the mobile phase, a flow rate of 1 mL/min, and photometric detection at 254 nm. PABA and APAP-cystein-S-yl (APAP-Cys) eluted at ~14.7 min and 22.7 min, respectively. Method linearity, based on on-column concentrations of APAP-Cys, was observed over the range 0.078-40 μg. Recoveries of APAP-Cys from spiked blank liver homogenates ranged from ~83% to 91%. Limits of detection and of quantification of APAP-Cys, based on column concentrations, were 0.06 μg and 0.14 μg, respectively. RSD values for interday and intraday analyses of a blank liver homogenate spiked with APAP-Cyst at three levels were, in all cases, ≤1.0% and <1.5%, respectively. The proposed method was found appropriate for comparing the antidotal properties of N-acetylcysteine and taurine in a rat model of APAP poisoning.

Fibrin(ogen)-independent role of plasminogen activators in acetaminophen-induced liver injury

Hepatic fibrin(ogen) has been noted to occur after acetaminophen (APAP)-induced liver injury in mice. Deficiency in plasminogen activator inhibitor-1 (PAI-1), an endogenous inhibitor of fibrinolysis, increases APAP-induced liver injury in mice. However, the roles of fibrinogen and fibrinolysis in APAP-induced liver injury are not known. We tested the hypothesis that hepatic fibrin(ogen) deposition reduces severity of APAP-induced liver injury. APAP-induced (300 mg/kg) liver injury in mice was accompanied by thrombin generation, consumption of plasma fibrinogen, and deposition of hepatic fibrin. Neither fibrinogen depletion with ancrod nor complete fibrinogen deficiency [via knockout of the fibrinogen alpha chain gene (Fbg(-/-))] affected APAP-induced liver injury. PAI-1 deficiency (PAI-1(-/-)) increased APAP-induced liver injury and hepatic fibrin deposition 6 hours after APAP administration, which was followed by marked hemorrhage at 24 hours. As in PAI-1(-/-) mice, administration of recombinant tissue plasminogen activator (tenecteplase, 5 mg/kg) worsened APAP-induced liver injury and hemorrhage in wild-type mice. In contrast, APAP-induced liver injury was reduced in both plasminogen-deficient mice and in wild-type mice treated with tranexamic acid, an inhibitor of plasminogen activation. Activation of matrix metalloproteinase 9 (MMP-9) paralleled injury, but MMP-9 deficiency did not affect APAP-induced liver injury. The results indicate that fibrin(ogen) does not contribute to development of APAP-induced liver injury and suggest rather that plasminogen activation contributes to APAP-induced liver injury.

Comparison of the sequential organ failure assessment score with the King's College Hospital criteria and the model for end-stage liver disease score for the prognosis of acetaminophen-induced acute liver failure

Acetaminophen-induced acute liver failure (ALF) is a complex multiorgan illness. An assessment of the prognosis is essential for the accurate identification of patients for whom survival without liver transplantation (LT) is unlikely. The aims of this study were the comparison of prognostic models [King's College Hospital (KCH), Model for End-Stage Liver Disease, Sequential Organ Failure Assessment (SOFA), and Acute Physiology and Chronic Health Evaluation II (APACHE II)] and the identification of independent prognostic indicators of outcome. We evaluated consecutive patients with severe acetaminophen-induced ALF who were admitted to the intensive care unit. At admission, demographic, clinical, and laboratory parameters were recorded. The discriminative ability of each prognostic score at the baseline was evaluated with the area under the receiver operating characteristic curve (AUC). In addition, using a multiple logistic regression, we assessed independent factors associated with outcome. In all, 125 consecutive patients with acetaminophen-induced ALF were evaluated: 67 patients (54%) survived with conservative medical management (group 1), and 58 patients (46%) either died without LT (28%) or underwent LT (18%; group 2). Group 1 patients had significantly lower median APACHE II (10 versus 14) and SOFA scores (9 versus 12) than group 2 patients (P < 0.001). The independent indicators associated with death or LT were a longer prothrombin time (P = 0.007), the inspiratory oxygen concentration (P = 0.005), and the lactate level at 12 hours (P < 0.001). The KCH criteria had the highest specificity (83%) but the lowest sensitivity (47%), and the SOFA score had the best discriminative ability (AUC = 0.79). In conclusion, for patients with acetaminophen-induced ALF, the SOFA score performed better than the other prognostic scores, and this reflected the presence of multiorgan dysfunction. A further evaluation of SOFA with the KCH criteria is warranted.

Tournefortia sarmentosa extract attenuates acetaminophen-induced hepatotoxicity

CONTEXT

Tournefortia sarmentosa Lam. (Boraginaceae), a Chinese herbal medicine, is commonly used as a detoxicant or anti-inflammatory agent.

OBJECTIVE

As acetaminophen (APAP) is a well-known hepatotoxin, we investigated the effect of the aqueous extract of the T. sarmentosa on APAP-induced hepatotoxicity in vivo and in vitro.

MATERIALS AND METHODS

Levels of liver function markers serum glutamate oxaloacetate transaminase (SGOT), glutamate pyruvate transaminase (SGPT), and alkaline phosphatase (ALP), inflammatory markers tumor necrosis factor (TNF)-α, interleukin (IL)-1b, and IL-6 in serum, and antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx), as well as lipid peroxidation were determined.

RESULTS

T. sarmentosa significantly reduced the elevated liver function (SGOT, SGPT, and ALP, p < 0.01) and inflammatory markers (TNF-α, IL-1β, and IL-6, p < 0.01) in serum of APAP-intoxicated rats. Malondialdehyde level (p < 0.05) and antioxidant enzyme levels (CAT, SOD, and GPx, p < 0.05) were also reduced in APAP-intoxicated rats treated with T. sarmentosa. Incubation of rat hepatocyte cell line clone-9 cells with APAP reduced cell viability and increased the extent of lipid peroxidation. APAP stimulation also reduced the level of glutathione (GSH) and caused reduction in the activities of the antioxidant enzymes, CAT, SOD, and GPx. Pretreatment of hepatocytes with T. sarmentosa aqueous extract before and during APAP stimulation attenuated the extent of lipid peroxidation, increased cell viability and GSH level, and enhanced the activities of antioxidant enzymes.

DISCUSSION AND CONCLUSION

These data suggest that the aqueous extract of T. sarmentosa can prevent APAP-induced hepatotoxicity.

Molecular mechanisms underlying chemical liver injury

The liver is necessary for survival. Its strategic localisation, blood flow and prominent role in the metabolism of xenobiotics render this organ particularly susceptible to injury by chemicals to which we are ubiquitously exposed. The pathogenesis of most chemical-induced liver injuries is initiated by the metabolic conversion of chemicals into reactive intermediate species, such as electrophilic compounds or free radicals, which can potentially alter the structure and function of cellular macromolecules. Many reactive intermediate species can produce oxidative stress, which can be equally detrimental to the cell. When protective defences are overwhelmed by excess toxicant insult, the effects of reactive intermediate species lead to deregulation of cell signalling pathways and dysfunction of biomolecules, leading to failure of target organelles and eventual cell death. A myriad of genetic factors determine the susceptibility of specific individuals to chemical-induced liver injury. Environmental factors, lifestyle choices and pre-existing pathological conditions also have roles in the pathogenesis of chemical liver injury. Research aimed at elucidating the molecular mechanism of the pathogenesis of chemical-induced liver diseases is fundamental for preventing or devising new modalities of treatment for liver injury by chemicals.

Prescription-acquired acetaminophen use and potential overuse patterns: 2001-2008

BACKGROUND

Food and Drug Administration advisory committees recently made some recommendations to address acetaminophen (APAP)-related toxicity.

OBJECTIVES

To study the proportion of APAP users potentially consuming APAP over the currently recommended dosage (4 g/day) and a toxic dosage (10 g/day). To explore the impact of substituting the APAP strength in combination prescriptions to 325 mg on potential APAP overuse patterns.

METHODS

Using the 2001-2008 pharmacy claims from IMS LifeLink Health Plans, APAP potential maximum daily dose (PMDD), potential cumulative dose, and potential average daily dose (PADD) were calculated annually for APAP users. The proportion of users with potential APAP use above 4 g/day and 10 g/day are reported. Analyses were repeated by substituting the maximum APAP strength in combination prescriptions to 325 mg. Ordinary least squares regression was used to detect linear trends in APAP use/overuse.

RESULTS

790 188 of 2 656 161 study subjects were prescribed APAP in one or more years from 2001 to 2008. 32.62% and 26.84% of the adult APAP users had a PMDD > 4 gm/day in 2001 and 2008 while 1.88% and 3.17% had a PMDD > 10 gm/day. If the maximum APAP strength in combination prescriptions was 325 mg, the proportion of APAP users with PMDD > 4 g would be 14.08% in 2001 and 13.67% in 2008, whereas the proportion of those with PMDD > 10 g would be 0.21% and 2.30%, respectively.

CONCLUSION

About one in four APAP users have a PMDD > 4 g/day, whereas 2-3% have a PMDD > 10 g based exclusively on prescription data, which is concerning. These proportions could reduce by over half if the maximum APAP strength in combination prescriptions is 325 mg. Additional monitoring of opioid prescription-patterns, physician and pharmacist cognizance in prescribing APAP-containing combination products, and dose-reduction strategies should be considered to reduce APAP overuse.

Gap junction inhibition prevents drug-induced liver toxicity and fulminant hepatic failure

Drug-induced liver injury (DILI) limits the development and application of many therapeutic compounds and presents major challenges to the pharmaceutical industry and clinical medicine. Acetaminophen-containing compounds are among the most frequently prescribed drugs and are also the most common cause of DILI. Here we describe a pharmacological strategy that targets gap junction communication to prevent amplification of fulminant hepatic failure and acetaminophen-induced hepatotoxicity. We demonstrate that connexin 32 (Cx32), a key hepatic gap junction protein, is an essential mediator of DILI by showing that mice deficient in Cx32 are protected against liver damage, acute inflammation and death caused by liver-toxic drugs. We identify a small-molecule inhibitor of Cx32 that protects against liver failure and death in wild-type mice when co-administered with known hepatotoxic drugs. These findings indicate that gap junction inhibition could provide a pharmaceutical strategy to limit DILI and improve drug safety.

Surveillance of suspected adverse reactions to herbal products used as laxatives

AIM

To describe and evaluate spontaneous reports of suspected adverse reactions (ARs) associated with herbal laxatives received by the Italian Medicines Agency and the Italian National Institute of Health between April 2002 and January 2011.

METHODS

Spontaneous reports of suspected ARs were individually analyzed by a multidisciplinary group of experts, and a causality assessment was performed.

RESULTS

Twenty-six reactions were reported during the study period. Of these, eight were associated with herbal medicinal products and 18 were related to herbal food supplements. Almost 80% of the reports on ARs involved women. The ARs, classified by System Organ Class, were associated with gastrointestinal, skin and subcutaneous tissue, and hepatobiliary disorders. Fifty percent of the reactions were serious, with the patients requiring hospitalization; of these, one was life-threatening. Most of the herbal remedies associated with the reported ARs contained liquorice, dandelion, and/or plants containing anthraquinones. Possible causes of the ARs were long-term use, idiosyncratic reactions or hypersensitivity, and interaction with other treatments. All of these factors and the presence of a large number of components in the same product increased the unpredictability of the final effect.

CONCLUSIONS

The total number of 26 ARs recorded in 8 years is limited; however, the an under-reporting effect cannot be excluded. Moreover, taking into account the seriousness of the reported ARs, the low number of reports does not represent a guarantee of safety. To reduce the risk of an adverse outcome, herbal laxatives should be used only over the short term.

Aldo-keto reductase-7A protects liver cells and tissues from acetaminophen-induced oxidative stress and hepatotoxicity

Aldo-keto reductase-7A (AKR7A) is an enzyme important for bioactivation and biodetoxification. Previous studies suggested that Akr7a might be transcriptionally regulated by oxidative stress-responsive transcription factor nuclear factor erythroid 2 p45-related factor 2 (Nrf2), a protein highly responsive to acetaminophen (APAP) or its intermediate metabolite, N-acetyl-p-benzoquinoneimine (NAPQI). This study was, therefore, carried out to investigate whether Akr7a is involved in the protection against APAP-induced oxidative stress and hepatotoxicity. We found that in response to APAP or NAPQI exposure, Akr7a3 mRNA and protein were significantly up-regulated in vitro in human HepG2 and LO2 cells. Similarly, strong induction was observed for Akr7a5 in mouse AML12 hepatocytes exposed to APAP. In vivo in wild-type rats, significant up-regulation of hepatic AKR7A1 protein was observed after administration of APAP. On the other hand, depletion of Nrf2 reduced the expression of Akr7a3, suggesting that Nrf2, indeed, contributes significantly to the induction of Akr7a. Moreover, loss of cell viability in Nrf2-depleted cells was significantly rescued by coexpression of AKR7A3. Furthermore, increased AKR7A3 in HepG2 cells was associated with the up-regulation of oxidative stress-related enzymes to enhance cellular antioxidant defense, which appeared to contribute significantly to protection against APAP-induced toxicity. In a line of transgenic rats overexpressing AKR7A1, increased AKR7A1 stimulated the expression of Nrf2 and other Nrf2-regulated genes, but did not better protect rats from APAP insults. In contrast, depletion of Akr7a5 in vitro in cultured AML12 cells or depletion of Akr7a1 in vivo in rat liver greatly increased APAP-induced hepatotoxicity.

CONCLUSION

AKR7A proteins are significantly up-regulated in response to APAP/NAPQI exposure to contribute significantly to protection against APAP-induced hepatotoxicity. AKR7A mediates this protection, in part, through enhancing hepatocellular antioxidant defense.

Effect of N-acetylcysteine on vasospasm in subarachnoid hemorrhage

Vasospasm remains an extremely serious complication that affects patients presenting with subarachnoid hemorrhage (SAH) due to ruptured intracranial aneurysms. The current therapeutic armamentarium is still insufficient in many cases, and the search for new therapies is necessary. In this study, we evaluated the effect of N-acetylcysteine (NAC) on cerebral arterial vasospasm using an experimental model. Twenty-four wistar rats were divided into 4 groups: [1] Control, [2] SAH, [3] SAH+NAC and [4] SAH+Placebo. The experimental model employed double subarachnoid injections of autologous blood. The proposed dose of NAC was 250 mg/kg intraperitoneally per day. We analyzed the inner area of the basilar artery to assess the action of NAC. The experimental model proved to be very adequate, with a mortality rate of 4%. The inner area of the basilar artery in the SAH group showed significant difference to the control group (p=0.009). The use of NAC significantly reduced vasospasm as compared to the untreated group (p=0.048) and established no significant difference to the control group (p=0.098). There was no significant improvement with the administration of placebo (p=0.97). The model of the dual hemorrhage proved to be very useful for vasospasm simulation, with overall low mortality. The administration of NAC significantly reduced vasospasm resulting from SAH, and may represent a new therapeutic alternative.

Dendritic cell depletion exacerbates acetaminophen hepatotoxicity

Acetaminophen (APAP) overdose is one of the most frequent causes of acute liver failure in the United States and is primarily mediated by toxic metabolites that accumulate in the liver upon depletion of glutathione stores. However, cells of the innate immune system, including natural killer (NK) cells, neutrophils, and Kupffer cells, have also been implicated in the centrilobular liver necrosis associated with APAP. We have recently shown that dendritic cells (DCs) regulate intrahepatic inflammation in chronic liver disease and, therefore, postulated that DC may also modulate the hepatotoxic effects of APAP. We found that DC immune-phenotype was markedly altered after APAP challenge. In particular, liver DC expressed higher MHC II, costimulatory molecules, and Toll-like receptors, and produced higher interleukin (IL)-6, macrophage chemoattractant protein-1 (MCP-1), and tumor necrosis factor alpha (TNF-α). Conversely, spleen DC were unaltered. However, APAP-induced centrilobular necrosis, and its associated mortality, was markedly exacerbated upon DC depletion. Conversely, endogenous DC expansion using FMS-like tyrosine kinase 3 ligand (Flt3L) protected mice from APAP injury. Our mechanistic studies showed that APAP liver DC had the particular capacity to prevent NK cell activation and induced neutrophil apoptosis. Nevertheless, the exacerbated hepatic injury in DC-depleted mice challenged with APAP was independent of NK cells and neutrophils or numerous immune modulatory cytokines and chemokines.

CONCLUSION

Taken together, these data indicate that liver DC protect against APAP toxicity, whereas their depletion is associated with exacerbated hepatotoxicity.

Conservative treatment for neck pain: medications, physical therapy, and exercise

This article offers conservative treatment strategies for patients suffering from musculoskeletal causes of neck pain. Basic pharmacology is reviewed, including that of opioids, nonsteroidal anti-inflammatory drugs, adjuvants, and topical analgesics. Moreover, indications for therapeutic exercise, manual therapy, and modalities are reviewed, along with any supporting literature. Treatment considerations with each category of medication and physical therapy are discussed. This article is meant to serve as a resource for physicians to tailor conservative treatment options to their individual patients.

Polyinosinic-polycytidylic acid suppresses acetaminophen-induced hepatotoxicity independent of type I interferons and toll-like receptor 3

Viral infections are often linked to altered drug metabolism in patients; however, the underlying molecular mechanisms remain unclear. Here we describe a mechanism by which activation of antiviral responses by the synthetic double-stranded RNA ligand, polyinosinic-polycytidylic acid (polyI:C), leads to decreased acetaminophen (APAP) metabolism and hepatotoxicity. PolyI:C administration down-regulates expression of retinoic X receptor-α (RXRα) as well as its heterodimeric partner pregnane X receptor (PXR) in mice. This down-regulation results in suppression of downstream cytochrome P450 enzymes involved in conversion of APAP to its toxic metabolite. Although the effects of polyI:C on drug metabolism are often attributed to interferon production, we report that polyI:C can decrease APAP metabolism in the absence of the type I interferon receptor. Furthermore, we demonstrate that polyI:C can attenuate APAP metabolism through both its membrane-bound receptor, Toll-like receptor 3 (TLR3), as well as cytoplasmic receptors.

CONCLUSION

This is the first study to illustrate that in vivo administration of polyI:C affects drug metabolism independent of type I interferon production or in the absence of TLR3 through crosstalk between nuclear receptors and antiviral responses.

Evaluation of the dose range of etoricoxib in an acute pain setting using the postoperative dental pain model

OBJECTIVE

This study was conducted to evaluate the dose range of etoricoxib in acute pain using the postoperative dental pain model further.

METHODS

This double-blind, randomized controlled study evaluated etoricoxib (90 and 120 mg), ibuprofen (600 mg), and acetaminophen (600 mg/codeine) (60 mg, (A/C)) in patients aged ≥ 18 years with moderate or severe pain after surgical extraction of ≥ 2 third molars (≥ 1 impacted). The patients reported pain intensity and pain relief over 24 hours. The primary efficacy endpoint was total pain relief over 6 hours (TOPAR6). Adverse events were evaluated throughout the study.

RESULTS

There were 588 patients randomized to placebo (n=46),etoricoxib (90 mg (n=191)), etoricoxib (120 mg (n=97)), ibuprofen(2400 mg (n=192)), and A/C (n=62). The overall analgesic effect (TOPAR6) of etoricoxib (90, 120 mg) was significantly greater than that of placebo (P ≤ 0.001), and not inferior to that of ibuprofen; no discernible difference was observed between etoricoxib 90 and 120 mg. Both etoricoxib doses were superior to A/C (P ≤ 0.001). Etoricoxib (90 and 120 mg) and ibuprofen(2400 mg) were generally well tolerated and had a similar incidence of adverse events (AEs). A/C was associated with significantly more AEs that led to discontinuation (ie, nausea and vomiting).

CONCLUSIONS

Etoricoxib (90 and 120 mg) showed similar efficacy in the postoperative dental pain model, which was noninferior to ibuprofen and superior to A/C. A higher number of tooth extractions or a higher mean impaction score may have led to a greater separation in efficacy between the 2 etoricoxib doses.

Depletion of activated hepatic stellate cell correlates with severe liver damage and abnormal liver regeneration in acetaminophen-induced liver injury

Hepatic stellate cells (HSCs) are important part of the local 'stem cell niche' for hepatic progenitor cells (HPCs) and hepatocytes. However, it is unclear as to whether the products of activated HSCs are required to attenuate hepatocyte injury, enhance liver regeneration, or both. In this study, we performed 'loss of function' studies by depleting activated HSCs with gliotoxin. It was demonstrated that a significantly severe liver damage and declined survival rate were correlated with depletion of activated HSCs. Furthermore, diminishing HSC activation resulted in a 3-fold increase in hepatocyte apoptosis and a 66% decrease in the number of proliferating hepatocytes. This was accompanied by a dramatic decrease in the expression levels of five genes known to be up-regulated during hepatocyte replication. In particular, it was found that depletion of activated HSCs inhibited oval cell reaction that was confirmed by decreased numbers of Pank-positive cells around the portal tracts and lowered gene expression level of cytokeratin 19 (CK19) in gliotoxin-treated liver. These data provide clear evidence that the activated HSCs are involved in both hepatocyte death and proliferation of hepatocytes and HPCs in acetaminophen (APAP)-induced acute liver injury.

Opioid therapy for osteoarthritis and chronic low back pain

BACKGROUND

Chronic low back pain (CLBP) and osteoarthritis (OA) of any joint are highly prevalent, occurring in > 50% of US adults aged ≥ 60 years. Opioids are prescribed more frequently for CLBP and OA than for any other noncancer pain, and the judicious use of opioids is recommended by treatment guidelines for the management of CLBP and OA pain.

OBJECTIVE

To review the appropriate role of opioid analgesics in the treatment of patients with moderate-to-severe pain due to CLBP or OA and provide recommendations for best practices when prescribing opioids.

METHODS

Articles were identified through a search of PubMed. Additional references were identified for inclusion from the reference lists of articles identified via the literature search, treatment guidelines, and Cochrane Reviews.

RESULTS

The available data suggest that opioid therapy represents a valuable treatment option in patients who do not respond to other analgesics and in whom the potential benefits of treatment outweigh the potential risks. Prescribing physicians need to perform vigilant patient screening and monitoring for signs of abuse, intervene promptly to manage or prevent adverse events and drug interactions, tailor opioid therapy to individual patients' comorbidities, and know how to switch or rotate opioids to find the best treatment option.

CONCLUSIONS

Prescribers need to understand the place of opioid therapy in a multimodal treatment program that includes patient rehabilitation to reduce pain and improve function. The analgesic benefits of opioids must be balanced against concerns about addiction and abuse, adverse events, and their potential impact on other aspects of treatment.

Acetaminophen pharmacokinetics in children with nonalcoholic fatty liver disease

OBJECTIVES

: The aim of the study was to evaluate UDP-glucuronyltransferase activity and the pharmacokinetics of a single oral dose of acetaminophen (APAP) in children with nonalcoholic fatty liver disease (NAFLD).

PATIENTS AND METHODS

: Twelve boys 10 to 17 years old with biopsy-proven NAFLD and 12 age- and sex-matched controls without NAFLD were recruited. Following administration of a single oral dose of APAP (5 mg/kg, maximum 325 mg), APAP and its glucuronide metabolite (APAP-G) were measured in plasma, urine, and sputum at various intervals up to 24 hours. The activity of UDP-glucuronyltransferase was estimated by the plasma ratio of APAP-G to APAP at 4 hours.

RESULTS

: Following administration of APAP, children with NAFLD had significantly higher concentrations of APAP-G in serum (P = 0.0071) and urine (P = 0.0210) compared with controls. No significant differences in APAP pharmacokinetics parameters were observed between the 2 groups.

CONCLUSIONS

: APAP glucuronidation is altered in children with fatty liver disease. Despite the altered disposition of this metabolite, the pharmacokinetics of a single 5 mg/kg dose of APAP is the same in children with NAFLD as in children with normal liver function.

Impact of serum acetaminophen concentration on changes in serum potassium, creatinine and urea concentrations among patients with acetaminophen overdose

BACKGROUND

Acetaminophen overdose may be accompanied by electrolyte disturbances. The basis for electrolyte change appears to be due to increased fractional urinary electrolyte excretion.

PURPOSE

This study investigated the impact of serum acetaminophen concentration on changes in serum potassium, creatinine and urea concentrations in patients with acetaminophen overdose.

METHODS

This was a retrospective cohort study which included patients admitted to the emergency department and hospital within 24 h of acetaminophen ingestion. The study was conducted over a period of 5 years from 1 January 2004 to 31 December 2008. Data are presented as mean ± SD and as medians (interquartile range) and groups were compared using independent two-tailed Student t-test. Statistical Package for Social Sciences (SPSS) 15 was used for data analysis.

RESULTS

Two hundred and eighty-three patients were studied (44 males and 239 females), mean age 23 ± 7.5 years. Patients who had a serum acetaminophen concentration above a 'possible toxicity' treatment line were associated with an elevation in serum creatinine concentration (p=0.044) and a reduction in the serum potassium concentration (p<0.001) but were not associated with a reduction in serum urea concentration (p>0.99). During the study period, 63.3% (179 patients) had serum potassium concentrations less than the normal concentration (3.5 mmol/l) and 31.4% (89 patients) had serum urea concentrations less than the normal concentration (2.5 mmol/l). The serum creatinine concentration in all patients was within the normal range.

CONCLUSIONS

Acetaminophen appears to cause a concentration-dependent reduction of potassium concentrations and an elevation of creatinine concentrations of short duration (<24 h) after overdose.

A new treatment strategy for acute liver failure

Acute liver failure (ALF) is a syndrome defined by coagulopathy and encephalopathy and no effective treatments have been established, except for liver transplantation. However, considering the limited supply of donors, we should endeavor to prevent the progression of this syndrome in its early stage to improve the prognosis of patients with ALF. Recently, several authors have reported that over-activation of intrahepatic macrophages plays an important role in the progression of ALF and we have developed a new treatment method, transcatheter arterial steroid injection therapy (TASIT), to suppress macrophage activation. We have now used TASIT for 5 years and have found that TASIT is effective for patients with over-activation of macrophages in the liver but not for those with lesser activation of macrophages. Therefore, to identify the most appropriate patients for TASIT, we tried to categorize patients with ALF or acute liver injury according to markers for the degree of intrahepatic macrophage activation. This approach was helpful to select the appropriate treatment including liver transplantation. We believe that it is essential to analyze disease progression in each patient before selecting the most appropriate treatment.

Assessing the impact of vomiting episodes on outcome after acetaminophen poisoning

Identifying indices of poor prognosis at first presentation after acetaminophen poisoning is the key to both improving clinical care and determining targets for intervention. This study intended to document the prevalence, clinical characteristics and predictors of vomiting and to investigate the relationship between episodes of vomiting at first hospital presentation and outcome in acetaminophen poisoning. This retrospective cohort study included patients who attended the emergency department and were admitted within 24 hr of acetaminophen ingestion. The study was conducted over a period of 5 years from 1 January 2004 to 31 December 2008. Parametric and non-parametric tests were used to test differences between groups depending on the normality of the data. SPSS 15 was used for data analysis. Data from 291 patients were included. Vomiting was present in 65.3% of patients with acetaminophen poisoning at the time of first presentation. Multiple logistic regression showed that significant risk factors for vomiting were present among patients who reported an ingested dose of acetaminophen ≥10 g (p < 0.001) and a latency time of more than 8 hr (p = 0.030). Overall, an increasing trend in prothrombin time (p = 0.03), serum bilirubin (p < 0.001), serum creatinine (p = 0.005), serum potassium (p < 0.001), length of hospital stay (p < 0.001) and the prevalence of patients who had a serum acetaminophen level above a 'possible toxicity' treatment line (p = 0.001) were associated with an increased number of episodes of vomiting. In conclusion, vomiting was common among patients with acetaminophen poisoning. This study suggests that an increase in episodes of vomiting at first presentation appears to be an important risk marker of subsequent nephrotoxicity and hepatotoxicity.

Effects of delay in infusion of N-acetylcysteine on appearance of adverse drug reactions after acetaminophen overdose: a retrospective study

PURPOSE

To investigate the relationship between different types of adverse drug reaction (ADR) and late time to N-acetylcysteine (NAC) infusion in patients presenting to the hospital with acetaminophen overdose.

METHODS

This is a retrospective study of patients admitted to the hospital for acute acetaminophen overdose over a period of 5 years (1 January 2004 to 31 December 2008). The primary outcome of interest was the relationship between ADR, if any, and late time to NAC infusion. Parametric and non-parametric tests were used to test differences between groups depending on the normality of the data. SPSS 15 was used for data analysis.

RESULTS

Of 305 patients with acetaminophen overdose, 146 (47.9%) were treated with intravenous NAC and 139 (45.6%) were included in this study. Different types of ADR were observed in 94 (67.6%) patients. Late time to NAC infusion was significantly associated with cutaneous anaphylactoid reactions when compared to patients without this type of ADR (p  <  0.001). However, there were no significant differences in time to NAC infusion between patients with and without the following ADR: gastrointestinal reactions (p = 0.11), respiratory reactions (p = 0.77), central nervous reactions (p = 0.64), and cardiovascular reactions (p = 0.63).

CONCLUSION

Late time to NAC infusion is a risk factor for developing cutaneous anaphylactoid reactions, suggesting, rather than proving, that early NAC infusion (≤ 8 hours) may be protective against this type of ADR.

High prevalence of hypokalemia after acute acetaminophen overdose: impact of psychiatric illness

BACKGROUND

Hypokalemia is not an isolated disease but an associated finding in a number of different diseases. It is also a commonly neglected condition among patients with acute acetaminophen overdose.

OBJECTIVES

This study intended to determine the prevalence of hypokalemia and its clinical correlates in acute psychiatric illness among hypokalemic and normokalemic patients after acetaminophen overdose.

METHODS

This is a retrospective cohort study of hospital admissions for acute acetaminophen overdose conducted over a period of 5 years from 1 January 2004 to 31 December 2008. Demographic data and different types of psychiatric illness were compared between hypokalemic and normokalemic patients. Hypokalemia was predefined by a serum concentration <3.5 mmol/L. Statistical Package for Social Sciences (SPSS) 15 was used for data analysis.

RESULTS

Two hundred and eighty patients out of 305 admissions were studied. Hypokalemia was found in 63.6% of patients with a higher prevalence in the presence of psychiatric illness (67.7%). Hypokalemic patients were significantly associated with the presence of major depression (p = .04), adjustment disorder (p < .001), anxiety (p = .01), and suicidal attempts (p = .04).

CONCLUSION

Hypokalemia was common among patients with psychiatric illness and acute acetaminophen overdose.

Removal of opioid/acetaminophen combination prescription pain medications: assessing the evidence for hepatotoxicity and consequences of removal of these medications

Opioid/acetaminophen combination products are widely prescribed for the management of moderate to moderately severe pain. Acetaminophen, when improperly used, can lead to liver damage and even acute liver failure. In June 2009, an FDA advisory committee recommended elimination of prescription acetaminophen combination products because of the risk of hepatotoxicity associated with use of these medications. The FDA advisory committee reviewed numerous observational studies and adverse event reporting data. The aims of this article are to: 1) provide a summary and epidemiologic critique of the studies and evidence the FDA advisory committee reviewed; 2) examine the potential consequences, such as poorly managed pain or a shift to treatment with other medications with greater potential toxicity and/or restricted availability, if the FDA follows the advisory committee vote; and 3) outline alternate strategies the FDA should consider for reducing hepatotoxicity associated with opioid/acetaminophen combination products.

Phase 1, placebo-controlled, dose escalation trial of chicory root extract in patients with osteoarthritis of the hip or knee

BACKGROUND

Extracts of chicory root have anti-inflammatory properties in vitro and in animal models of arthritis. The primary objective of this investigator-initiated, Phase 1, placebo-controlled, double blind, dose-escalating trial was to determine the safety and tolerability of a proprietary bioactive extract of chicory root in patients with osteoarthritis (OA). Secondary objectives were to assess effects on the signs and symptoms of this disorder.

METHODS

Individuals greater than 50 years of age with OA of the hip or knee were eligible for trial entry. A total of 40 patients were enrolled in 3 cohorts and were treated with escalating chicory doses of 600 mg/day, 1200 mg/day and 1800 mg/day for 1 month. The ratio of active treatment to placebo was 5:3 in cohorts 1 and 2 (8 patients) each and 16:8 in cohort 3 (24 patients). Safety evaluations included measurement of vital signs and routine lab tests at baseline and the end of the treatment period. Efficacy evaluations at baseline and final visits included self-assessment questionnaires and measurement of the 25-foot walking time.

RESULTS

In the highest dose cohort, 18 patients who completed treatment per protocol were analyzed for efficacy. In this group, 13 patients showed at least 20% improvement in the defined response domains of pain, stiffness and global assessment: 9 of 10 (90%) patients randomized to active treatment with chicory and 4 of 8 (50%) patients randomized to placebo (P = 0.06). In general, the treatment was well-tolerated. Only one patient who was treated with the highest dose of chicory had to discontinue treatment due to an adverse event.

CONCLUSIONS

The results of this pilot study suggest that a proprietary bioactive extract of chicory root has a potential role in the management of OA and merits further investigation. Clinicaltrials.gov identifier: NCT 01010919.

Review article: drug-induced liver injury in clinical practice

BACKGROUND

Drug-induced liver injury (DILI) is an important differential diagnosis in many patients in clinical hepatology. DILI is the leading cause of acute liver failure and is an important safety issue when new drugs are developed.

AIMS

To provide a review of the recent data on DILI with particular focus on the most common and relevant issues seen in clinical practice.

METHODS

A Medline search was undertaken to identify relevant literature using search terms including 'drug-induced liver injury' and 'hepatotoxicity'.

RESULTS

The true incidence of DILI remains unknown but incidence up to 14 cases per 100 000 inhabitants and year has been reported. Antibiotics, analgesics and NSAIDs are the most common drugs causing liver injury. Idiosyncratic DILI has been shown to have a dose-dependent component and drugs without significant hepatic metabolism rarely cause DILI. Chronic elevation in liver enzymes can develop after DILI but this is rarely associated with clinical morbidity or mortality.

CONCLUSIONS

Drug-induced liver injury remains a diagnostic challenge. Multicentre studies and international collaborative work with well-characterized patients will increase our understanding of liver injury associated with drugs. New therapies for acute liver failure resulting from drugs are needed.

Activation of the farnesoid X receptor provides protection against acetaminophen-induced hepatic toxicity

The nuclear receptor, farnesoid X receptor (FXR, NR1H4), is known to regulate cholesterol, bile acid, lipoprotein, and glucose metabolism. In the current study, we provide evidence to support a role for FXR in hepatoprotection from acetaminophen (APAP)-induced toxicity. Pharmacological activation of FXR induces the expression of several genes involved in phase II and phase III xenobiotic metabolism in wild-type, but not Fxr(-/-) mice. We used chromatin immunoprecipitation-based genome-wide response element analyses coupled with luciferase reporter assays to identify functional FXR response elements within promoters, introns, or intragenic regions of these genes. Consistent with the observed transcriptional changes, FXR gene dosage is positively correlated with the degree of protection from APAP-induced hepatotoxicity in vivo. Further, we demonstrate that pretreatment of wild-type mice with an FXR-specific agonist provides significant protection from APAP-induced hepatotoxicity. Based on these findings, we propose that FXR plays a role in hepatic xenobiotic metabolism and, when activated, provides hepatoprotection against toxins such as APAP.