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

Integrated strategy of network pharmacology, molecular docking, HPLC-DAD and mice model for exploring active ingredients and pharmacological mechanisms of Penthorum chinense Pursh against alcoholic liver injury

ETHNOPHARMACOLOGICAL RELEVANCE

Penthorum chinense Pursh (PCP, Saxifragaceae) is an edible plant and frequently-used Chinese herbal medicine, and is commonly used as Miao medicine in China. It showed well effect on alcoholic liver injury (ALI), but studies on its active ingredients and mechanisms against ALI remain at the starting stage.

AIM OF THE STUDY

This work aims to explore the active ingredients and pharmacological mechanisms of PCP against ALI.

MATERIALS AND METHODS

First, network pharmacology was applied to decipher the potential active ingredients and pharmacological mechanisms of PCP against ALI by ingredient identification, ADMET evaluation, target identification, network construction and analysis, protein-protein interaction (PPI) analysis, and gene enrichment analysis. Second, molecular docking was used to explore the interaction between key active ingredient and hub protein of PCP against ALI. Then, the ingredient analysis of PCP aqueous extract and semiquantitative analysis of key active ingredient were carried out on HPLC-DAD. Subsequently, mice with ALI were used to investigate the therapeutic effect or verify the predicted mechanisms of PCP or key active ingredient against ALI by analyzing body weight, liver index, ALT and AST activities in serum and liver tissues, oxidation related indices (SOD activity, GSH level and MDA level) in liver tissues, histopathology of liver tissues (oil red O, hematoxylin-eosin and DAB-TUNEL staining), and changes of related proteins (PI3K, Akt, p-Akt, Bax and Bcl-2) in liver tissues with the aid of Western blot.

RESULTS

Network pharmacology showed that the active ingredients and related genes of PCP against ALI comprised 10 ingredients and 52 genes. Based on the result of ingredient analysis of PCP aqueous extract, quercitrin was identified as the key active ingredient of PCP against ALI. PPI analysis indicated that AKT1 was the hub gene of PCP against ALI, and molecular docking suggested that there were good interaction between quercetin and Akt1 protein. Gene enrichment analysis showed that the pivotal molecular mechanism of PCP against ALI might be to inhibit hepatocyte apoptosis via activation of PI3K-Akt signaling pathway. PCP and quercitrin showed anti-ALI effect by offsetting weight loss and increase of liver index, and reversing the imbalance of oxidative stress and histopathological changes of liver tissues (abnormal fatty acid metabolism, hepatic cord swelling and inflammatory cell infiltration) in mice with ALI. PCP caused the decrease of DAB-TUNEL-positive cells, upregulated the anti-apoptotic proteins (PI3K, Akt and p-Akt) levels and the ratio of p-Akt/Akt, and downregulated pro-apoptotic protein (Bax) level and the ratio of Bax/Bcl-2 in liver tissues of mice with ALI, indicating that the mechanism of PCP against ALI involved in inhibiting hepatocyte apoptosis via activation of PI3K-Akt signaling pathway.

CONCLUSION

PCP and quercitrin showed well anti-ALI effect. The key active ingredient of PCP against ALI was identified as quercitrin. The underlying pharmacological mechanisms of PCP against ALI may be related to PI3K-Akt signaling pathway-mediated inhibition of hepatocyte apoptosis. This work provided new evidence to support the application of PCP in treatment of ALI, and a research basis for the research and development of functional foods or drugs against ALI from PCP.

Adverse Drug Reactions in the Intensive Care Unit

Adverse drug reactions (ADRs) are undesirable effects of medications used in normal doses [1]. ADRs can occur during treatment in an intensive care unit (ICU) or result in ICU admissions. A meta-analysis of 4139 studies suggests the incidence of ADRs among hospitalized patients is 17% [2]. Because of underreporting and misdiagnosis, the incidence of ADRs may be much higher and has been reported to be as high as 36% [3]. Critically ill patients are at especially high risk because of medical complexity, numerous high-alert medications, complex and often challenging drug dosing and medication regimens, and opportunity for error related to the distractions of the ICU environment [4]. Table 1 summarizes the ADRs included in this chapter.

Evidence for the changing regimens of acetylcysteine

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

Global research productivity of N-acetylcysteine use in paracetamol overdose: A bibliometric analysis (1976-2012)

PURPOSE

The main objective of this study was to examine the publication pattern of N-acetylcysteine (NAC) research output for paracetamol overdose at the global level.

METHODS

Data were searched for documents that contained specific words regarding NAC and paracetamol as keywords in the title and/or abstract and/or keywords. Scientific output was evaluated based on a methodology developed and used in other bibliometric studies. Research productivity was adjusted to the national population and nominal gross domestic product per capita.

RESULTS

The criteria were met by 367 publications from 33 countries. The highest number of articles associated with the use of NAC in paracetamol overdose was from the United States of America (USA; 39.78%), followed by the United Kingdom (UK; 11.99%). After adjusting for economy and population power, USA (2.822), Iran (1.784) and UK (1.125) had the highest research productivity. The total number of citations at the time of data analysis (14 March 2014) was 8785 with an average of 23.9 citations per document and a median (interquartile range) of 6 (1-22). The h-index of the retrieved documents was 48. The highest h-index was 32 for USA, followed by 20 for UK. Furthermore, the highest number of collaborations with international authors for each country was held by USA with 11 countries, followed by Canada with 7 countries.

CONCLUSION

The amount of NAC-based research activity was low in some countries, and more effort is needed to bridge this gap and to promote better evaluation of NAC use worldwide. Our findings demonstrate that NAC use for paracetamol overdose remains a hot issue in scientific research and may have a larger audience compared with other toxicological aspects. Editors and authors in the field of toxicology might usefully promote the submission of work on NAC in future to improve their journal's impact.

Effect of amlodipine, lisinopril and allopurinol on acetaminophen-induced hepatotoxicity in rats

Background

Exposure to chemotherapeutic agents such as acetaminophen may lead to serious liver injury. Calcium deregulation, angiotensin II production and xanthine oxidase activity are suggested to play mechanistic roles in such injury.

Objective

This study evaluates the possible protective effects of the calcium channel blocker amlodipine, the angiotensin converting enzyme inhibitor lisinopril, and the xanthine oxidase inhibitor allopurinol against experimental acetaminophen-induced hepatotoxicity, aiming to understand its underlying hepatotoxic mechanisms.

Material and methods

Animals were allocated into a normal control group, a acetaminophen hepatotoxicity control group (receiving a single oral dose of acetaminophen; 750 mg/kg/day), and four treatment groups receive N-acetylcysteine (300 mg/kg/day; a reference standard), amlodipine (10 mg/kg/day), lisinopril (20 mg/kg/day) and allopurinol (50 mg/kg/day) orally for 14 consecutive days prior to acetaminophen administration. Evaluation of hepatotoxicity was performed by the assessment of hepatocyte integrity markers (serum transaminases), oxidative stress markers (hepatic malondialdehyde, glutathione and catalase), and inflammatory markers (hepatic myeloperoxidase and nitrate/nitrite), in addition to a histopathological study.

Results

Rats pre-treated with amlodipine, lisinopril or allopurinol showed significantly lower serum transaminases, significantly lower hepatic malondialdehyde, myeloperoxidase and nitrate/nitrite, as well as significantly higher hepatic glutathione and catalase levels, compared with acetaminophen control rats. Serum transaminases were normalized in the lisinopril treatment group, while hepatic myeloperoxidase was normalized in the all treatment groups. Histopathological evaluation strongly supported the results of biochemical estimations.

Conclusion

Amlodipine, lisinopril or allopurinol can protect against acetaminophen-induced hepatotoxicity, showing mechanistic roles of calcium channels, angiotensin converting enzyme and xanthine oxidase enzyme in the pathogenesis of hepatotoxicity induced by acetaminophen.

Availability of treatment resources for the management of acute toxic exposures and poisonings in emergency departments among various types of hospitals in Palestine: a cross-sectional study

BACKGROUND

Poisoning exposures continue to be a significant cause of morbidity and mortality worldwide. The lack of facilities, treatment resources, and antidotes in hospitals may affect the treatments provided and outcomes. This study aimed to determine the availability of gastrointestinal (GI) decontamination, stabilisation, elimination enhancement resources, and antidotes for the management of acute toxic exposures and poisonings in emergency departments (EDs) among various types of governmental and private hospitals in Palestine.

METHODS

A cross-sectional study using semi-structured questionnaire was performed. Data were collected based on hospital resources; GI decontamination, stabilisation, elimination enhancement resources and antidotes from Palestinian hospitals.

RESULTS

Eighteen hospitals (94.7%) have responded. Among them, paracetamol poisoning was the most frequently reported cases by EDs (mean frequency score = 7.6 ± 2.1), followed by bee stings (mean = 6.9 ± 2.7) and organophosphate poisoning (mean = 6.7 ± 2.7). The availabilities of most resources related to GI decontamination items varied substantially with hospital type, but these differences were not statistical significant. The availability of stabilisation resources was not significantly different between hospitals types. For the availability of techniques used to enhance the elimination of toxic substances, there were variations between the hospitals types. However, these differences were not statistical significant, except for haemodialysis (p = 0.003) which was more available in governmental hospitals. For the availability of antidotes, none of the hospitals had sufficient stock of all antidotes listed. In relation to hospital type, there was variability in the availability of antidotes, but this did not reach statistical significance, except for deferoxamine (p < 0.001), which was available in all governmental hospitals but none of the private hospitals.

CONCLUSIONS

The availability of treatment resources and antidotes in Palestinian hospitals was not adequate except for stabilisation resources. The availability of such resources acts as a marker for the level of readiness of hospital EDs in Palestine for the management of acute toxic exposure and poisoning. The implementation of a minimum list of antidotes and treatment resources would be useful to increase the level of resources. Coordination between Palestinian poison control and drug information centre and hospitals is also important.

Early Risk Factors of Moderate/Severe Hepatotoxicity After Suicide Attempts With Acetaminophen in 11- to 15-Year-Old Children

Objective. To characterize early risk factors of moderate/severe hepatotoxicity in a pediatric population with acetaminophen overdose, due to suicide attempt, admitted to a general secondary-level pediatric department. Methods. A retrospective case study of 107 patients, 11 to 15 years old. Results. There was a highly significant relationship between the number of episodes of prehospital vomiting and several elevated hepatologically relevant biochemical parameters, for example, maximum aspartate aminotransferase (P = .0001). The duration of the latency time before initiation of N-acetylcysteine treatment was significantly related to the elevation of several hepatologically relevant biochemical parameters (eg, maximum γ-glutamyl transferase; P = .0001). Patients suffering from illness prior to their suicide attempt had significantly greater elevations of their hepatologically relevant biochemical parameters, for example, maximum alanine aminotransferase (P = .01) levels than healthy patients. Conclusion. By use of risk factors, it is possible to identify pediatric patients at increased risk of moderate/severe hepatotoxicity at an early stage of admission.

Novel acetylcysteine regimens for treatment of paracetamol overdose

Paracetamol (acetaminophen) overdose remains the leading cause of death or transplantation due to acute liver failure in many parts of the world. Acetylcysteine has long been recognized as an effective antidote, via oral or intravenous administration, minimizing the risk and severity of acute liver injury if administered sufficiently early after a paracetamol overdose. Despite this, its mechanisms of action remain obscure, and there is uncertainty regarding the optimal dose and duration of treatment. The intravenous infusion protocol was originally developed as a three-step loading regimen; it causes very high early peak plasma concentrations of acetylcysteine whereas the later maintenance infusion is associated with much lower concentrations. This pharmacokinetic profile is associated with two particular concerns: a high rate of occurrence of adverse effects that occur after the initial loading infusion, and the possibility that the maintenance phase of treatment might deliver too low a dose of acetylcysteine for optimum protection against liver injury. Recently described novel administration regimens offer different rates of intravenous acetylcysteine administration in both the loading and maintenance phases. These alternative regimens appear to be well tolerated in small patient groups, but too few clinical data are available to evaluate their comparative efficacy in preventing paracetamol-induced liver injury.

Evaluate the impact of hospital types on the availability of antidotes for the management of acute toxic exposures and poisonings in Malaysia

INTRODUCTION

The availability of antidotes may be considered essential and lifesaving in the management of certain poisonings. Surveys carried out in a number of countries have demonstrated inadequate availability of a variety of poisoning antidotes.

OBJECTIVES

The purpose of this study was to determine the availability of antidote stocking at hospitals, based on published guidelines for antidote stocking, and to evaluate the impact of hospital types on the availability of antidotes for the management of acute toxic exposures and poisonings in Malaysia.

METHODS

A questionnaire on the availability of antidotes was sent to all government accident and emergency departments in Malaysia. The list of commonly required antidotes and essential drugs was compiled from published guidelines. Collected data were analysed in SPSS version 16 using descriptive and comparative analysis.

RESULTS

The response rate was 59.06%. None of the responding hospitals stocked all of the antidotes on the lists. In relation to hospital type, there was great variability in the availability of antidotes (there were significant differences between hospitals for 13 antidotes). The availabilities of most antidotes were far better in the General Hospitals and the District Hospitals with specialists compared to District Hospitals without specialists. Calcium gluconate, sodium bicarbonate, atropine sulphate, naloxone, flumazenil, vitamin K, and pyridoxine were available at all general hospitals. Atropine sulphate and naloxone were available at all district hospitals with specialists.

CONCLUSION

Most Malaysian government hospitals stocked some important antidotes. Raising awareness of the importance of antidotes by education, regular review of antidote storage, distribution plans, and appropriate legislation might provide solutions. Coordination between Malaysian hospitals and the National Poison Centre at Universiti Sains Malaysia is also important.

Reliability of the reported ingested dose of acetaminophen for predicting the risk of toxicity in acetaminophen overdose patients

PURPOSE

The present study examines the relationship between the dose of acetaminophen reported to have been ingested by patients and the occurrence of serum acetaminophen levels above the 'possible toxicity' line in patients presenting at the hospital after acetaminophen overdose. The prognostic value of patient-reported dosage cut-offs of 8, 10 and 12 g was determined.

METHODS

This retrospective cohort study included patients admitted to the emergency department or hospital within 24 hours of acetaminophen ingestion. Serum acetaminophen concentrations were considered to be the gold standard, and specificity, sensitivity and positive/negative predictive values were calculated from the reported ingested dose, to predict toxicity using the Rumack-Matthew nomogram (i.e. the 'possible toxicity' treatment line) and standard equations.

RESULTS

Of 305 patients identified, 291 met the study inclusion criteria, and 121 (41.6%) had serum acetaminophen concentrations above the 'possible toxicity' treatment line. The range of patient-reported acetaminophen ingested was 1-75 g, with 185 patients (63.6%) reporting ≥8 g. One hundred eighteen patients (97.5%) who reported ingesting ≥8 g had serum acetaminophen concentrations above the '150-line', compared with only three patients (2.5%) who reported ingesting <8 g (p < 0.001). The positive predictive value of a patient-reported dose ≥8 g for predicting serum acetaminophen concentrations above the 'possible toxicity' treatment line was 63.78%, with a negative predictive value of 97.17%. The sensitivity of patient-reported doses ≥8 g was high (97.52%) but with low specificity (60.59%). The sensitivity of patient-reported doses ≥10 g also was high (89.26%) with low specificity (65.29%), whereas the sensitivity of ≥12 g dose was low (61.16%) with high specificity (86.47%).

CONCLUSIONS

Patient-reported doses of acetaminophen are good risk indicators for acetaminophen overdose patients in Malaysia. Patient-reported ingestion of ≥8 g (as a cut-off dose) had a higher sensitivity than ≥10 g or ≥12 g. The results of this study have important implications for toxicity risk evaluations in areas with poor serum acetaminophen assay availability.