A systematic review of ethanol and fomepizole use in toxic alcohol ingestions

Awareness raising and dealing with methanol poisoning based on effective strategies

Intoxication with methanol most commonly occurs as a consequence of ingesting, inhaling, or coming into contact with formulations that include methanol as a base. Clinical manifestations of methanol poisoning include suppression of the central nervous system, gastrointestinal symptoms, and decompensated metabolic acidosis, which is associated with impaired vision and either early or late blindness within 0.5-4 h after ingestion. After ingestion, methanol concentrations in the blood that are greater than 50 mg/dl should raise some concern. Ingested methanol is typically digested by alcohol dehydrogenase (ADH), and it is subsequently redistributed to the body's water to attain a volume distribution that is about equivalent to 0.77 L/kg. Moreover, it is removed from the body as its natural, unchanged parent molecules. Due to the fact that methanol poisoning is relatively uncommon but frequently involves a large number of victims at the same time, this type of incident occupies a special position in the field of clinical toxicology. The beginning of the COVID-19 pandemic has resulted in an increase in erroneous assumptions regarding the preventative capability of methanol in comparison to viral infection. More than 1000 Iranians fell ill, and more than 300 of them passed away in March of this year after they consumed methanol in the expectation that it would protect them from a new coronavirus. The Atlanta epidemic, which involved 323 individuals and resulted in the deaths of 41, is one example of mass poisoning. Another example is the Kristiansand outbreak, which involved 70 people and resulted in the deaths of three. In 2003, the AAPCC received reports of more than one thousand pediatric exposures. Since methanol poisoning is associated with high mortality rates, it is vital that the condition be addressed seriously and managed as quickly as feasible. The objective of this review was to raise awareness about the mechanism and metabolism of methanol toxicity, the introduction of therapeutic interventions such as gastrointestinal decontamination and methanol metabolism inhibition, the correction of metabolic disturbances, and the establishment of novel diagnostic/screening nanoparticle-based strategies for methanol poisoning such as the discovery of ADH inhibitors as well as the detection of the adulteration of alcoholic drinks by nanoparticles in order to prevent methanol poisoning. In conclusion, increasing warnings and knowledge about clinical manifestations, medical interventions, and novel strategies for methanol poisoning probably results in a decrease in the death load.

Delayed reversal of methanol-induced blindness in an adult by a combination of erythropoietin and a high dose of methylprednisolone: a case report

BACKGROUND

The clinical manifestation following methanol toxicity accounts for a life-threatening problem that contributes to metabolic disorders, neurological complications, blindness, and even death. There is no completely effective treatment to retain the patient's vision. Herein, we apply a new therapeutic strategy for the recovery of bilateral blindness in a patient who had ingested methanol.

CASE PRESENTATION

A 27-year-old Iranian man with complete bilateral blindness was referred 3 days after accidental ingestion of methanol to the poisoning center at Jalil Hospital, Yasuj, Iran, in 2022. After taking his medical history, performing neurologic and ophthalmologic examinations, and routine laboratory tests, ordinary management was undertaken and counterpoisons were given for 4-5 days; however, the blindness did not reverse. Following the 4-5 days of unsuccessful standard management, he was given ten doses of subcutaneous erythropoietin 10,000 IU/12 hours twice daily, folinic acid 50 mg/12 hours, and methylprednisolone 250 mg/6 hours for 5 days. After five days, vision of both eyes recovered, reaching 1/10 in the left and 7/10 in the right eye. He remained under daily supervision until his release from the hospital, and he was discharged from the hospital 15 days post admission. In outpatient follow-up, his visual acuity was improved without having any side effects at 2 weeks after discharge.

CONCLUSION

A combination of erythropoietin and a high dose of methylprednisolone were useful for relieving the critical optic neuropathy and improved the optical neurological disorder following methanol toxicity.

Extracorporeal treatment for ethylene glycol poisoning: systematic review and recommendations from the EXTRIP workgroup

Ethylene glycol (EG) is metabolized into glycolate and oxalate and may cause metabolic acidemia, neurotoxicity, acute kidney injury (AKI), and death. Historically, treatment of EG toxicity included supportive care, correction of acid-base disturbances and antidotes (ethanol or fomepizole), and extracorporeal treatments (ECTRs), such as hemodialysis. With the wider availability of fomepizole, the indications for ECTRs in EG poisoning are debated. We conducted systematic reviews of the literature following published EXTRIP methods to determine the utility of ECTRs in the management of EG toxicity. The quality of the evidence and the strength of recommendations, either strong ("we recommend") or weak/conditional ("we suggest"), were graded according to the GRADE approach. A total of 226 articles met inclusion criteria. EG was assessed as dialyzable by intermittent hemodialysis (level of evidence = B) as was glycolate (Level of evidence = C). Clinical data were available for analysis on 446 patients, in whom overall mortality was 18.7%. In the subgroup of patients with a glycolate concentration ≤ 12 mmol/L (or anion gap ≤ 28 mmol/L), mortality was 3.6%; in this subgroup, outcomes in patients receiving ECTR were not better than in those who did not receive ECTR. The EXTRIP workgroup made the following recommendations for the use of ECTR in addition to supportive care over supportive care alone in the management of EG poisoning (very low quality of evidence for all recommendations): i) Suggest ECTR if fomepizole is used and EG concentration > 50 mmol/L OR osmol gap > 50; or ii) Recommend ECTR if ethanol is used and EG concentration > 50 mmol/L OR osmol gap > 50; or iii) Recommend ECTR if glycolate concentration is > 12 mmol/L or anion gap > 27 mmol/L; or iv) Suggest ECTR if glycolate concentration 8-12 mmol/L or anion gap 23-27 mmol/L; or v) Recommend ECTR if there are severe clinical features (coma, seizures, or AKI). In most settings, the workgroup recommends using intermittent hemodialysis over other ECTRs. If intermittent hemodialysis is not available, CKRT is recommended over other types of ECTR. Cessation of ECTR is recommended once the anion gap is < 18 mmol/L or suggested if EG concentration is < 4 mmol/L. The dosage of antidotes (fomepizole or ethanol) needs to be adjusted during ECTR.

Methanol poisoning in the emergency department: a retrospective study

Aim: Massive methanol poisonings have occurred in the past decades, resulting in a large number of deaths. In this study, our aim is to retrospectively analyze methanol poisoning cases admitted to the emergency department between 2019-2021, to evaluate their demographic characteristics, causes of poisoning, clinical and laboratory findings, treatments applied and mortality, and to contribute to the poisoning data of our country. Material and Method: The cases of methanol poisoning who applied to the emergency department in a 3-year period were analyzed retrospectively. Medical files of patients aged 18 years and older were reviewed. Patients diagnosed with 'methanol poisoning' as a result of the examination were included in the study. Results: A total of 59 patients were included in the study. 88% (n=52) of the patients with a mean age of 53±10 were male. The presence of neurological symptoms and GCS were associated with mortality among the symptoms of patients presenting to the emergency department (p=0.017, p

Treating ethylene glycol poisoning with alcohol dehydrogenase inhibition, but without extracorporeal treatments: a systematic review

CONTEXT

Ethylene glycol is metabolized to toxic metabolites that cause acute kidney injury, metabolic acidemia, and death. The treatment of patients with ethylene glycol poisoning includes competitively inhibiting alcohol dehydrogenase with ethanol or fomepizole to prevent the formation of toxic metabolites, and extracorporeal treatments such as hemodialysis to remove ethylene glycol and its metabolites. In the absence of significant metabolic acidemia or kidney injury, it is hypothesized that extracorporeal treatments may be obviated without adverse outcomes to the patient if alcohol dehydrogenase inhibitors are used.

OBJECTIVES

The objectives of this study are to: (1) identify indicators predicting ADH inhibitor failure in patients with ethylene glycol poisoning treated with either ethanol or fomepizole for whom extracorporeal treatment was not performed (aside from rescue therapy, see below) (prognostic study), and (2) validate if the anion gap, shown in a previous study to be the best surrogate for the glycolate concentration, is associated with acute kidney injury and mortality (anion gap study).

METHODS

We conducted a systematic review to identify all reported patients with ethylene glycol poisoning treated without extracorporeal treatments but with either fomepizole (fomepizole monotherapy) or ethanol (ethanol monotherapy). Analyses were performed using both one case per patient and all cases (if multiple events were reported for a single patient). Data were compiled regarding poisoning, biochemistry, and outcomes. Treatment failure was defined as mortality, worsening of acid-base status, extracorporeal treatments used as rescue, or a worsening of kidney or neurological function after alcohol dehydrogenase inhibition was initiated. Also, we performed an analysis of previously described anion gap thresholds to determine if they were associated with outcomes such as acute kidney injury and mortality.

RESULTS

Of 115 publications identified, 96 contained case-level data. A total of 180 cases were identified with ethanol monotherapy, and 231 with fomepizole monotherapy. Therapy failure was noted mostly when marked acidemia and/or acute kidney injury were present prior to therapy, although there were cases of failed ethanol monotherapy with minimal acidemia (suggesting that ethanol dosing and/or monitoring may not have been optimal). Ethylene glycol dose and ethylene glycol concentration were predictive of monotherapy failure for ethanol, but not for fomepizole. In the anion gap study (207 cases), death and progression of acute kidney injury were almost nonexistent when the anion gap was less than 24 mmol/L and mostly observed when the anion gap was greater than 28 mmol/L.

CONCLUSION

This review suggests that in patients with minimal metabolic acidemia (anion gap <28 mmol/L), fomepizole monotherapy without extracorporeal treatments is safe and effective regardless of the ethylene glycol concentration. Treatment failures were observed with ethanol monotherapy which may relate to transient subtherapeutic ethanol concentrations or very high ethylene glycol concentrations. The results are limited by the retrospective nature of the case reports and series reviewed in this study and require prospective validation.

Oxidative stress and biochemical indicators in blood of patients addicted to alcohol treated for acute ethylene glycol poisoning

Ethylene glycol (EG), in addition to its neurotoxic and nephrotoxic effects, evokes oxidative stress. The aim of this study was to assess the influence of the ethylene glycol on the biochemical indicators and oxidoreductive balance of patients treated for acute poisoning. The total study group consisted of 56 persons including 26 alcoholics who took EG as a substitute for ethyl alcohol in the course of alcohol dependence syndrome and 30 controls. Severity of poisoning, results of acid-base parameters, biochemical, and toxicological tests as well as biomarkers of the oxidative stress in blood were analyzed during the patients' hospitalization. The key issue was to assess the oxidative stress and biochemical disturbances caused by EG and the type of treatment applied in the course of poisoning. Significant changes in some parameters were found both at time of diagnosis and after treatment initiation (ethanol as an antidote and hemodialysis). The most important differences included the activity of hepatic parameters (aspartate aminotransferase, AST) and oxidative stress markers like catalase (CAT); correlation of the lipid peroxidation products level (TBARS) with urea concentration has been shown. On the last day of the hospitalization, in some cases, the mutual correlation between the evaluated markers were observed, for example, between alanine transaminase (ALT) and glutathione reductase (GR), and urea concentration and glutathione level (GSH/GSSG). The concentration of ions (H⁺) had a major impact on the oxidoreductive balance, correlating with the elevated GR and GSH/GSSG levels.

Analysis of fomepizole safety based on a 16-year post-marketing experience in France

Introduction: Fomepizole has been recommended as first-line antidote to treat ethylene glycol and methanol poisoning. Despite more than 30 years of utilization, the safety of fomepizole when used clinically has not been well documented. Based on the long-standing clinical experience with fomepizole in France, we investigated its safety profile in patients treated for suspected toxic alcohol poisoning.Methods: We designed a 16-year post-marketing study to evaluate the indications for fomepizole prescriptions and to investigate its safety. Data were retrospectively collected using a standardized questionnaire sent each month by post to each French hospital that ordered fomepizole during the month before. The response rate to our survey was 59%.Results: Five hundred and thirty-six patients [188 females/348 males; age, 46 years [34-55] (median [25th-75th percentiles])] were treated with fomepizole [cumulative dose, 18.6 mg/kg [15.5-26.3] (1,268 mg [900-2,100])]. Ethylene glycol/methanol poisoning was confirmed in 275 patients (51%) while a nontoxic exposure was diagnosed in 147 patients (27%). Toxic alcohol poisoning was misdiagnosed in the remaining 114 patients (21%), before the assessment of an alternative poisoning or non-poisoning diagnosis. Fifty adverse reactions were attributed to fomepizole in 36 patients (7%) including general reactions (N = 22), local reactions (N = 22) and laboratory test impairments (N = 6). All were considered mild and transient. None required stopping fomepizole. The most frequent adverse effects were injection site pain/burning (N = 13), nausea/vomiting (N = 8), vessel puncture site inflammation (N = 7), drowsiness/confusion (N = 5) and serum aminotransferase elevation (N = 3). None of the fatalities (N = 37, 7%) or persistent symptoms on discharge (N = 9; 2%) was related to fomepizole.Conclusion: Our longitudinal cohort study supports the safety of fomepizole administered to treat presumed EG and methanol poisoning.

Prediction of Human Pharmacokinetics of Fomepizole from Preclinical Species Pharmacokinetics Based on Normalizing Time Course Profiles

Fomepizole is used as an antidote to treat methanol poisoning due to its selectivity towards alcohol dehydrogenase. In the present study, the goal is to develop a method to predict the fomepizole human plasma concentration versus time profile based on the preclinical pharmacokinetics using the assumption of superimposability on simulated time course profiles of animals and humans. Standard allometric equations with/without correction factors were also assimilated in the prediction. The volume of distribution at steady state (Vss) predicted by simple allometry (57.55 L) was very close to the reported value (42.17 L). However, clearance (CL) prediction by simple allometry was at least 3-fold higher to the reported value (33.86 mL/min); hence, multiple correction factors were used to predict the clearance. Both brain weight and maximum life span potential could predict the CL with 1.22- and 1.01-fold difference. Specifically, the predicted Vss and CL values via interspecies scaling were used in the prediction of series of human intravenous pharmacokinetic parameters, while the simulation of human oral profile was done by the use of absorption rate constant (Ka) from dog following the applicability of human bioavailability value scaled from dog data. In summary, the findings indicate that the utility of diverse allometry approaches to derive the human pharmacokinetics of fomepizole after intravenous/oral dosing.

Acute kidney injury and the risk of mortality in patients with methanol intoxication

Background

Methanol poisoning is a serious public health issue in developing countries, but few data are available in the literature on acute kidney injury (AKI) after methanol intoxication.

Methods

This study examined the clinical features, spectrum and outcomes of AKI in patients with methanol intoxication and evaluated the predictors of mortality after methanol intoxication. A total of 50 patients with methanol intoxication were seen at Chang Gung Memorial Hospital between 2000 and 2013. Patients were grouped according to the status of renal damage as AKI (n = 33) or non-AKI (n = 19). Demographic, clinical, laboratory, and mortality data were obtained for analysis.

Results

Most patients were middle-aged (47.8 ± 14.9 years), predominantly male (74.0%), and habitual alcohol consumers (70.0%). Most incidents were oral exposures (96.0%) and unintentional (66.0%). Two (4.0%) patients attempted suicide by intravenous injection of methanol. Five (10.0%) patients suffered methanol intoxication after ingestion of methomyl pesticide that contained methanol as a solvent. Compared to non-AKI patients, the AKI patients were older (50.9 ± 13.7 versus 41.6 ± 15.6 years, P = 0.034), predominantly male (90.9% versus 42.8%, P = 0.000), more habitual alcohol users (84.8% versus 41.2%, P = 0.001) and had more unintentional exposures (82.8% versus 35.3%, P = 0.001). Furthermore, there was a higher incidence of respiratory failure (63.6% versus 29.4%, P = 0.022) in the AKI group than in the non-AKI group, respectively. The laboratory studies revealed that the AKI patients suffered from more severe metabolic acidosis than the non-AKI patients. By the end of this study, 13 (39.5%) AKI patients and 1 (5.9%) non-AKI patient had died. The overall in-hospital hospital mortality rate was 28%. In a multivariate binary logistic regression model, it was demonstrated that AKI (odds ratio 19.670, confidence interval 1.026–377.008, P = 0.048) and Glasgow coma scale score (odds ratio 1.370, confidence interval 1.079–1.739, P = 0.010) were significant factors associated with mortality. The Kaplan-Meier analysis disclosed that AKI patients suffered lower cumulative survival than non-AKI patients (log-rank test, chi-square = 5.115, P = 0.024).

Conclusions

AKI was common (66.0%) after methanol intoxication and was predictive of in-hospital hospital mortality. The development of AKI was associated with a 19.670-fold higher risk of in-hospital mortality.

Psychiatric comorbidities in patients with intentional methanol intoxication

BACKGROUND

Intentional methanol intoxication (IMI) is an emerging public health issue in Asian countries, but few data are available in the literature on underlying psychiatric comorbidities in these suicide attempters.

PATIENTS AND METHODS

We conducted a retrospective chart review on patients with methanol intoxication (MI) treated at Chang-Gung Memorial Hospital, Linkou, Taiwan during 2000-2016. Of the 56 cases of documented MI, 16 were IMI. Baseline demographic, clinical, laboratory, psychiatric diagnoses, and mortality data were collected and analyzed.

RESULTS

Patient group with IMI had more females (62.5% vs 7.5%, P=0.000), less alcohol consumption (33.3% vs 92.5%, P=0.000), and less smoking (40.0% vs 79.5%, P=0.009), but higher past psychiatric disease (73.3% vs 10.0%, P=0.000) and past suicide attempts (81.1% vs 2.5%, P=0.000) than patient group with unintentional MI (UMI). Pesticides (50.0%) comprised the most common source used for suicide, followed by industrial methanol (37.5%). There was no significant difference in mortality rates between these two group (25.0% vs 22.5%, P=0.548). Twelve (75.0%) survivors of IMI were referred to a psychiatric consultation-liaison team, and depressive disorder (58.3%) and adjustment disorder (25.0%) were common.

CONCLUSION

There is a female predominance and a high prevalence of psychiatric comorbidities, namely depression and adjustment disorder in patients with IMI. Besides, alcohol consumption is a prevalent but not adequately treated condition in UMI group.

In silico repositioning of approved drugs against Schistosoma mansoni energy metabolism targets

Schistosomiasis is a neglected parasitosis caused by Schistosoma spp. Praziquantel is used for the chemoprophylaxis and treatment of this disease. Although this monotherapy is effective, the risk of resistance and its low efficiency against immature worms compromises its effectiveness. Therefore, it is necessary to develop new schistosomicide drugs. However, the development of new drugs is a long and expensive process. The repositioning of approved drugs has been proposed as a quick, cheap, and effective alternative to solve this problem. This study employs chemogenomic analysis with use of bioinformatics tools to search, identify, and analyze data on approved drugs with the potential to inhibit Schistosoma mansoni energy metabolism enzymes. The TDR Targets Database, Gene DB, Protein, DrugBank, Therapeutic Targets Database (TTD), Promiscuous, and PubMed databases were used. Fifty-nine target proteins were identified, of which 18 had one or more approved drugs. The results identified 20 potential drugs for schistosomiasis treatment; all approved for use in humans.

Adolescent Presents With Altered Mental Status and Elevated Anion Gap After Suicide Attempt by Ethylene Glycol Ingestion

We report the case of a 16-year-old healthy adolescent male who presented to the local emergency department with altered mental status. En route to a tertiary care facility, he began to decompensate and was found to be markedly acidotic. Further investigation revealed an elevated anion gap, and physical examination showed only abdominal pain and decreased level of consciousness. A broad differential diagnosis was considered at the time of the patient's presentation at the tertiary care center including ingestion of a volatile alcohol, sepsis, and an abdominal catastrophe. Although fomepizole and emergent dialysis were being initiated, laboratory tests confirmed ethylene glycol poisoning. This case demonstrates the importance of early recognition of potential ingestions in patients with altered mental status and supportive laboratory findings.

Antidotes for poisoning by alcohols that form toxic metabolites

The alcohols, methanol, ethylene glycol and diethylene glycol, have many features in common, the most important of which is the fact that the compounds themselves are relatively non-toxic but are metabolized, initially by alcohol dehydrogenase, to various toxic intermediates. These compounds are readily available worldwide in commercial products as well as in homemade alcoholic beverages, both of which lead to most of the poisoning cases, from either unintentional or intentional ingestion. Although relatively infrequent in overall occurrence, poisonings by metabolically-toxic alcohols do unfortunately occur in outbreaks and can result in severe morbidity and mortality. These poisonings have traditionally been treated with ethanol since it competes for the active site of alcohol dehydrogenase and decreases the formation of toxic metabolites. Although ethanol can be effective in these poisonings, there are substantial practical problems with its use and so fomepizole, a potent competitive inhibitor of alcohol dehydrogenase, was developed for a hopefully better treatment for metabolically-toxic alcohol poisonings. Fomepizole has few side effects and is easy to use in practice and it may obviate the need for haemodialysis in some, but not all, patients. Hence, fomepizole has largely replaced ethanol as the toxic alcohol antidote in many countries. Nevertheless, ethanol remains an important alternative because access to fomepizole can be limited, the cost may appear excessive, or the physician may prefer ethanol due to experience.

Fomepizole in the treatment of acute methanol poisonings: experience from the Czech mass methanol outbreak 2012-2013

OBJECTIVE

During an outbreak of mass methanol poisonings in the Czech Republic in 2012-2013, fomepizole was applied as an alternative antidote to ethanol. We present the laboratory data, clinical features, adverse reactions, and treatment outcomes in all patients treated with fomepizole.

METHODS

Combined retrospective and prospective case series study in 25 patients, median age 50 (16-73) years, 18 males and 7 females.

RESULTS

There were 24% fatalities, 36% survivors without health impairment, and 40% survivors with sequelae. All the patients who died were comatose on admission; the mortality was 50% among patients in a coma. The median intensive care unit length of stay was six (2-22) days. The median total dose of fomepizole was 2 (1-9) g. Complications were observed in 7/25 cases: aspiration pneumonia (4), sepsis (2), bleeding (2), malignant arrhythmia (1), delirium tremens (1), and rebound of acidosis (1). The patients who survived without impairment were less acidotic than those who died or survived with sequelae (P<0.01). No difference in serum methanol and formate was found between the three groups.

CONCLUSION

There is no evidence whether fomepizole is a more efficient antidote than ethanol with regards to the hospital mortality. The possibility of delirium tremens in the patients with a history of chronic alcohol abuse has to be taken in consideration. The benefits of fomepizole were indirect: no need to monitor serum ethanol's level during the hemodialysis in severely poisoned patients and less working overload on ICU doctors treating several poisoned patients simultaneously.

Risk factors for mortality in Asian Taiwanese patients with methanol poisoning

Introduction

Methanol poisoning continues to be a serious public health issue in Taiwan, but very little work has been done to study the outcomes of methanol toxicity in the Asian population. In this study, we examined the value of multiple clinical variables in predicting mortality after methanol exposure.

Methods

We performed a retrospective observational study on patients with acute poisoning who were admitted to the Chang Gung Memorial Hospital over a period of 9 years (2000–2008). Out of the 6,347 patients, only 32 suffered methanol intoxication. The demographic, clinical, laboratory, and mortality data were obtained for analysis.

Results

Most patients were middle aged (46.1±13.8 years), male (87.5%), and habitual alcohol consumers (75.0%). All the poisonings were from an oral exposure (96.9%), except for one case of intentionally injected methanol (3.1%). After a latent period of 9.3±10.1 hours, many patients began to experience hypothermia (50.0%), hypotension (15.6%), renal failure (59.4%), respiratory failure (50.0%), and consciousness disturbance (Glasgow coma scale [GCS] score 10.5±5.4). Notably, the majority of patients were treated with ethanol antidote (59.4%) and hemodialysis (58.1%). The remaining 41.6% of patients did not meet the indications for ethanol therapy. At the end of analysis, there were six (18.8%), 15 (46.9%), and eleven (34.4%) patients alive, alive with chronic complications, and dead, respectively. In a multivariate Cox regression model, it was revealed that the GCS score (odds ratio [OR] 0.816, 95% confidence interval [CI] 0.682–0.976) (P=0.026), hypothermia (OR 168.686, 95% CI 2.685–10,595.977) (P=0.015), and serum creatinine level (OR 4.799, 95% CI 1.321–17.440) (P=0.017) were significant risk factors associated with mortality.

Conclusion

The outcomes (mortality rate 34.4%) of the Taiwanese patients subjected to intensive detoxification protocols were comparable with published data from other international poison centers. Furthermore, the analytical results indicate that GCS score, hypothermia, and serum creatinine level help predict mortality after methanol poisoning.