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McMartin K, Jacobsen D, Hovda KE. Antidotes for poisoning by alcohols that form toxic metabolites. Br J Clin Pharmacol 2024. [PMID: 39234820 DOI: 10.1111/bcp.16232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Revised: 08/08/2024] [Accepted: 08/13/2024] [Indexed: 09/06/2024] Open
Abstract
The alcohols methanol, ethylene glycol and diethylene glycol share many characteristics. The most important is that the compounds themselves are relatively nontoxic 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 poisonings, from either unintentional or intentional ingestion. Although relatively infrequent, toxic alcohol poisonings 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 an effective antidote, there are substantial practical problems with its use. Therefore 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.
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Affiliation(s)
- Kenneth McMartin
- Department of Pharmacology, Toxicology & Neuroscience, Louisiana State University Health Sciences Center-Shreveport, Shreveport, Louisiana, USA
| | - Dag Jacobsen
- Department of Acute Medicine, Division of Medicine, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- The National Poison Information Centre, National Institute of Health, Oslo, Norway
| | - Knut Erik Hovda
- Department of Acute Medicine, Division of Medicine, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- The National Poison Information Centre, National Institute of Health, Oslo, Norway
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2
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Filip AB, Mullins ME. Fomepizole should be used more liberally in paracetamol overdose. Br J Clin Pharmacol 2023; 89:594-598. [PMID: 36471569 DOI: 10.1111/bcp.15594] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/26/2022] [Accepted: 10/31/2022] [Indexed: 12/12/2022] Open
Abstract
Growing clinical and basic science data support the use of fomepizole as an adjunct to N-acetylcysteine in paracetamol poisoning. This safe antidote may be helpful in severely poisoned patients.
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Affiliation(s)
- Ari B Filip
- Arkansas Poison and Drug Information Center, University of Arkansas for Medical Sciences College of Pharmacy, Little Rock, Arkansas, USA
| | - Michael E Mullins
- Department of Emergency Medicine, Washington University in Saint Louis School of Medicine, Saint Louis, Missouri, USA
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3
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Stanton MT. Part
II
: Interactive case: Toxicology and poison control. JOURNAL OF THE AMERICAN COLLEGE OF CLINICAL PHARMACY 2022. [DOI: 10.1002/jac5.1725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Filip AB, Berg SE, Mullins ME, Schwarz ES. Fomepizole as an adjunctive therapy for acetaminophen poisoning: cases reported to the toxicology investigators consortium (ToxIC) database 2015-2020. Clin Toxicol (Phila) 2022; 60:1006-1011. [PMID: 35510880 DOI: 10.1080/15563650.2022.2070071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
INTRODUCTION Fomepizole inhibits formation of toxic acetaminophen (APAP) metabolites and may prevent or reverse mitochondrial toxicity. Given these mechanisms, it may be beneficial in patients with severe APAP toxicity. Current patterns of use for this indication are not well-studied. METHODS This is a secondary analysis of patients enrolled in the Toxicology Investigators Consortium (ToxIC) database from January 2015 to July 2020. We queried cases in which APAP was listed as an ingested agent and fomepizole was also administered. We excluded cases in which APAP was not the primary agent, N-acetylcysteine (NAC) was not administered, or fomepizole was explicitly administered for another indication. Additionally, we sent a survey to each ToxIC site that administered fomepizole for APAP toxicity to better understand when, why, and how they were using it for this indication. RESULTS Twenty-five cases of fomepizole administration following an APAP ingestion met our inclusion criteria. There were one to four cases per year between 2015 and 2019 and eight cases in 2020. Seventeen of 25 (68%) cases were for a known acute ingestion. Eighteen of 25 (72%) patients developed hepatotoxicity (AST or ALT > 1000 IU/L) and 10 of 25 (40%) developed coagulopathy (PT > 15s). This was an ill patient population, with 18 of 25 (72%) developing metabolic acidosis (pH <7.20), 12 of 25 (48%) were intubated, 9 of 25 (36%) receiving vasopressors, and 6 of 25 (24%) receiving continuous renal replacement therapy. Overall, mortality was 24%. CONCLUSION The use of fomepizole is increasing in frequency in a small subset of critically ill and acutely APAP-poisoned patients.
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Affiliation(s)
- Ari B Filip
- Department of Emergency Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Sarah E Berg
- The Toxikon Consortium, Department of Emergency Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Michael E Mullins
- Department of Emergency Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Evan S Schwarz
- Department of Emergency Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
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- American College of Medical Toxicology, Phoenix, AZ, USA
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McMartin K, Brent J. Analysis of Fomepizole Elimination in Methanol- and Ethylene Glycol-Poisoned Patients. J Med Toxicol 2022; 18:19-29. [PMID: 34697779 PMCID: PMC8758829 DOI: 10.1007/s13181-021-00862-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/05/2021] [Accepted: 10/12/2021] [Indexed: 01/03/2023] Open
Abstract
INTRODUCTION Fomepizole is an anti-metabolite therapy that is used to diminish the toxicity from methanol or ethylene glycol. Although its elimination kinetics have been well described in healthy human subjects, the elimination in poisoned patients have only been described in a few isolated cases. This study was designed to relate the elimination of fomepizole in a series of poisoned patients to that in healthy humans. METHODS Plasma samples from 26 patients in the clinical trials of the use of fomepizole for methanol and ethylene glycol poisoning were analyzed for fomepizole concentrations. The elimination of fomepizole was assessed after individual doses, both during and without intermittent hemodialysis. RESULTS In methanol- and ethylene glycol-poisoned patients, fomepizole had a volume of distribution of 0.66-0.68 L/kg. After repeated doses of fomepizole, the minimum trough concentration averaged 86-109 µmol/L, which is 10 times higher than the minimum therapeutic concentration. In healthy human subjects, fomepizole elimination follows Michaelis-Menten kinetics and has been calculated as zero-order elimination rates. Zero-order elimination rates averaged 13 and 17 μmol/L/h in methanol and ethylene glycol patients, respectively, compared to 6-19 μmol/L/h in healthy subjects. Elimination during intermittent hemodialysis followed first-order kinetics, with a half-life of 3 h. CONCLUSIONS Plasma concentrations during the repeated dosing confirmed that the recommended dosing schedule, with and without intermittent hemodialysis, maintained therapeutic concentrations throughout the treatments. Fomepizole elimination in poisoned patients at therapeutic plasma concentrations appears be similar to that reported previously in healthy human subjects.
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Affiliation(s)
- Kenneth McMartin
- Department of Pharmacology, Toxicology and Neuroscience, LSU Health Sciences Center - Shreveport, Shreveport, LA, 71130-3932, USA.
| | - Jeffrey Brent
- School of Medicine, University of Colorado, Aurora, CO, USA
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Nekoukar Z, Zakariaei Z, Taghizadeh F, Musavi F, Banimostafavi ES, Sharifpour A, Ebrahim Ghuchi N, Fakhar M, Tabaripour R, Safanavaei S. Methanol poisoning as a new world challenge: A review. Ann Med Surg (Lond) 2021; 66:102445. [PMID: 34141419 PMCID: PMC8187162 DOI: 10.1016/j.amsu.2021.102445] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/21/2021] [Accepted: 05/23/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Methanol poisoning (MP) occurs often via ingestion, inhalation, or dermal exposure to formulations containing methanol in base. Clinical manifestations of MP include gastrointestinal symptoms, central nervous system (CNS) suppression, and decompensated metabolic acidosis occurred with blurred vision and early or late blindness. OBJECTIVE This study reviewed the clinical manifestations, laboratory and radiology findings, and treatment approaches in MP. DISCUSSION Methanol is usually rapidly absorbed after ingestion and metabolized by alcohol dehydrogenase (ADH), then distributed to the body water to reach a volume distribution approximately equal to 0.77 L/kg. It is also eliminated from the body as unchanged parent compounds. Clinical manifestations of MP alone initiate within 0.5-4 h after ingestion and include gastrointestinal symptoms and CNS suppression. After a latent period of 6-24 h, depending on the absorbed dose, decompensated metabolic acidosis occurs with blurred vision and early or late blindness. Blurred vision with normal consciousness is a strong suspicious sign of an MP. The mortality and severity of intoxication are well associated with the severity of CNS depression, hyperglycemia, and metabolic acidosis, but not with serum methanol concentration. After initial resuscitation, the most important therapeutic action for patients with known or suspected MP is correction of acidosis, inhibition of ADH, and hemodialysis. CONCLUSION Since MP is associated with high morbidity and mortality, it should be considered seriously and instantly managed. Delay in treatment may cause complications, permanent damage, and even death.
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Affiliation(s)
- Zahra Nekoukar
- Department of Clinical Pharmacy, Faculty of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Zakaria Zakariaei
- Toxoplasmosis Research Center, Communicable Diseases Institute, Iranian National Registry Center for Lophomoniasis and Toxoplasmosis, Mazandaran University of Medical Sciences, Sari, Iran
- Toxicology and Forensic Medicine Division, Orthopedic Research Center, Imam Khomeini Hospital, Mazandaran University of Medical Sciences, Sari, Iran
| | - Fatemeh Taghizadeh
- Psychiatry and Behavioral Sciences Center, Addiction Institute, Mazandaran University of Medical Sciences, Sari, Iran
| | - Fatemeh Musavi
- Toxicology and Forensic Medicine Division, Orthopedic Research Center, Imam Khomeini Hospital, Mazandaran University of Medical Sciences, Sari, Iran
| | - Elham Sadat Banimostafavi
- Toxoplasmosis Research Center, Communicable Diseases Institute, Iranian National Registry Center for Lophomoniasis and Toxoplasmosis, Mazandaran University of Medical Sciences, Sari, Iran
| | - Ali Sharifpour
- Toxoplasmosis Research Center, Communicable Diseases Institute, Iranian National Registry Center for Lophomoniasis and Toxoplasmosis, Mazandaran University of Medical Sciences, Sari, Iran
- Pulmonary and Critical Care Division, Imam Khomeini Hospital, Iranian National Registry Center for Lophomoniasis (INRCL), Mazandaran University of Medical Sciences, Sari, Iran
| | - Nasrin Ebrahim Ghuchi
- Knowledge and Information Science, Imam Khomeini Hospital, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mahdi Fakhar
- Toxoplasmosis Research Center, Communicable Diseases Institute, Iranian National Registry Center for Lophomoniasis and Toxoplasmosis, Mazandaran University of Medical Sciences, Sari, Iran
| | - Rabeeh Tabaripour
- Toxoplasmosis Research Center, Communicable Diseases Institute, Iranian National Registry Center for Lophomoniasis and Toxoplasmosis, Mazandaran University of Medical Sciences, Sari, Iran
| | - Sepideh Safanavaei
- Toxoplasmosis Research Center, Communicable Diseases Institute, Iranian National Registry Center for Lophomoniasis and Toxoplasmosis, Mazandaran University of Medical Sciences, Sari, Iran
- Pulmonary and Critical Care Division, Imam Khomeini Hospital, Iranian National Registry Center for Lophomoniasis (INRCL), Mazandaran University of Medical Sciences, Sari, Iran
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Mullins ME, Yeager LH, Freeman WE. Metabolic and mitochondrial treatments for severe paracetamol poisoning: a systematic review. Clin Toxicol (Phila) 2020; 58:1284-1296. [PMID: 32762579 DOI: 10.1080/15563650.2020.1798979] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Paracetamol (acetaminophen) remains a leading cause of poisoning in Europe, North America, and Australia. For over four decades, acetylcysteine has been the antidote of choice. However, despite the use of acetylcysteine, some patients who ingest very large doses of paracetamol or who reach hospital late in the course of their poisoning, develop acute liver failure. Some will develop metabolic acidosis indicating mitochondrial toxicity. OBJECTIVE We review the experimental and clinical data reported with the use of cimetidine, fomepizole, and calmangafodipir in the treatment of paracetamol toxicity to determine if these treatments alone or in combination with acetylcysteine might be of benefit. METHODS We searched Ovid Medline 1946-2020, Embase 1947-2020, Scopus 2004-2020, Cochrane Databases of Systematic Reviews (CDSR), Cochrane Central Register of Controlled Trials (CENTRAL), and clinicaltrials.gov 1997-2020 for records including the concepts of paracetamol poisoning and cimetidine, fomepizole, calmangafodipir, and acetylcysteine. We included basic science studies in animals and all available study types in humans. We reviewed the reference lists of included articles to search for references missed in the original search. We registered the protocol in PROSPERO. RESULTS We completed all search strategies on 20 August 2019, 27 January 2020, and 15 June 2020. These produced 6,826 citations. We identified and deleted 2,843 duplicate resulting in a total of 3,856 unique citations. After applying inclusion and exclusion criteria, 89 studies remained. The largest numbers of studies described the past use of cimetidine, and the more recent use of fomepizole.Cimetidine: There is good animal evidence that cimetidine blocks CYP 2E1 with the potential to inhibit the toxic metabolism of paracetamol. Early case reports were inconclusive regarding the benefit to humans in paracetamol poisoning. Two comparative trials found no benefit of cimetidine in paracetamol poisoning, but few patients had severe poisoning.Fomepizole: There is good animal evidence that fomepizole blocks CYP 2E1 with the potential to inhibit the toxic metabolism of paracetamol. There are no comparative trials of fomepizole for acute paracetamol poisoning. Case reports are inconclusive due to multiple other interventions including the use of acetylcysteine in all cases. The benefit of fomepizole as adjunct treatment has not been demonstrated.Calmangafodipir: Calmangafodipir, a drug mimicking superoxide dismutase, has emerged as a potential treatment for severe paracetamol toxicity because the formation of superoxide free radicals appears to explain part of the mitochondrial toxicity of extremely large paracetamol overdoses. Calmangafodipir has reached Phase I/II trial of safety in humans with acute paracetamol overdose. Planning for a Phase III study of efficacy is currently underway. CONCLUSIONS The vast majority of patients with acute paracetamol overdose enjoy excellent outcomes with acetylcysteine alone. Although cimetidine and fomepizole inhibit CYP 2E1 in animals, there is insufficient evidence to recommend their use either as a primary treatment or adjunct therapy in paracetamol poisoning. Calmangafodipir remains investigational.
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Affiliation(s)
- Michael E Mullins
- Section of Medical Toxicology, Department of Emergency Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Lauren H Yeager
- School of Medicine, Bernard Becker Medical Library Medicine, Washington University, St. Louis, Missouri, USA
| | - William E Freeman
- Section of Medical Toxicology, Department of Emergency Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
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Shah KR, Fox C, Geib AJ, Murphy C, Kopec K, Kerns II W, Dulaney A, Beuhler MC. Fomepizole as an adjunctive treatment in severe acetaminophen ingestions: a case series. Clin Toxicol (Phila) 2020; 59:71-72. [DOI: 10.1080/15563650.2020.1775847] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Kartik R. Shah
- Atrium Health’s Carolinas Medical Center, Charlotte, NC, USA
| | - Carolyn Fox
- Atrium Health’s Carolinas Medical Center, Charlotte, NC, USA
| | | | | | - Kathryn Kopec
- Atrium Health’s Carolinas Medical Center, Charlotte, NC, USA
| | | | - Anna Dulaney
- Atrium Health’s Carolinas Medical Center, Charlotte, NC, USA
- North Carolina Poison Control, Charlotte, NC, USA
| | - Michael C. Beuhler
- Atrium Health’s Carolinas Medical Center, Charlotte, NC, USA
- North Carolina Poison Control, Charlotte, NC, USA
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Shah KR, Beuhler MC. Fomepizole as an Adjunctive Treatment in Severe Acetaminophen Toxicity. Am J Emerg Med 2019; 38:410.e5-410.e6. [PMID: 31785979 DOI: 10.1016/j.ajem.2019.09.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 09/20/2019] [Accepted: 09/23/2019] [Indexed: 11/30/2022] Open
Abstract
A 33-year-old male presented to the emergency department with a chief complaint of abdominal pain after taking #50 500 mg acetaminophen tablets over the preceding two days. He was tachycardic and tachypneic, and the initial labs were notable for acetaminophen level, 337 mg/L; AST, 137 IU/L; ALT, 194 IU/L; ABG pH, 7.24; and lactate, 4.1 mmol/L. The patient was started on IV N-Acetylcysteine (NAC) as well as given a single dose of 15 mg/kg fomepizole. The patient did remarkably well, with a peak AST of 198 IU/L, peak ALT of 301 IU/L, and peak INR of 3.1. Biochemical and animal data support fomepizole having hepatoprotective effects in acetaminophen poisoning. To our knowledge, this is the first human case of an intentional dual NAC/fomepizole regimen for severe acetaminophen toxicity.
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Affiliation(s)
- Kartik R Shah
- Division of Medical Toxicology, Department of Emergency Medicine, Atrium Health's Carolinas Medical Center, Medical Education Building, 3rd Floor, 1000 Blythe Blvd, Charlotte, NC, 28203, USA.
| | - Michael C Beuhler
- Division of Medical Toxicology, Department of Emergency Medicine, Atrium Health's Carolinas Medical Center, North Carolina Poison Control, 4400 Golf Acres Drive, Suite B-2, Charlotte, NC, 28203, USA.
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Marraffa JM, Stork CM, Howland MA. Comment on consensus statements on the approach to patients in a methanol poisoning outbreak. Clin Toxicol (Phila) 2019; 58:503. [DOI: 10.1080/15563650.2019.1660361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Jeanna M. Marraffa
- Department of Emergency Medicine, SUNY Upstate Medical University, Upstate New York Poison Center, Syracuse, NY, USA
| | - Christine M. Stork
- Department of Emergency Medicine, SUNY Upstate Medical University, Upstate New York Poison Center, Syracuse, NY, USA
| | - Mary Ann Howland
- Clinical Health Sciences, St. John's University College of Pharmacy, New York, NY, USA
- New York City Poison Control Center, New York, NY, USA
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Jairam RK, Mallurwar SR, Sulochana SP, Chandrasekhar DV, Todmal U, Bhamidipati RK, Richter W, Srinivas NR, Mullangi R. Prediction of Human Pharmacokinetics of Fomepizole from Preclinical Species Pharmacokinetics Based on Normalizing Time Course Profiles. AAPS PharmSciTech 2019; 20:221. [PMID: 31214899 DOI: 10.1208/s12249-019-1434-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 05/23/2019] [Indexed: 11/30/2022] Open
Abstract
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.
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Affiliation(s)
- Ravi Kumar Jairam
- Drug Metabolism and Pharmacokinetics, Jubilant Biosys, Industrial Suburb, Yeshwanthpur, Bangalore, 560 022, India
| | | | - Suresh P Sulochana
- Drug Metabolism and Pharmacokinetics, Jubilant Biosys, Industrial Suburb, Yeshwanthpur, Bangalore, 560 022, India
| | - Devaraj V Chandrasekhar
- Drug Metabolism and Pharmacokinetics, Jubilant Biosys, Industrial Suburb, Yeshwanthpur, Bangalore, 560 022, India
| | - Umesh Todmal
- Drug Metabolism and Pharmacokinetics, Jubilant Biosys, Industrial Suburb, Yeshwanthpur, Bangalore, 560 022, India
| | - Ravi Kanth Bhamidipati
- Drug Metabolism and Pharmacokinetics, Jubilant Biosys, Industrial Suburb, Yeshwanthpur, Bangalore, 560 022, India
| | - Wolfgang Richter
- TUBE Pharmaceuticals GmbH, Leberstr. 20, A-1110, Vienna, Austria
| | | | - Ramesh Mullangi
- Drug Metabolism and Pharmacokinetics, Jubilant Biosys, Industrial Suburb, Yeshwanthpur, Bangalore, 560 022, India.
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Kraut JA. Approach to the Treatment of Methanol Intoxication. Am J Kidney Dis 2016; 68:161-7. [DOI: 10.1053/j.ajkd.2016.02.058] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 02/04/2016] [Indexed: 11/11/2022]
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McMartin K, Jacobsen D, Hovda KE. Antidotes for poisoning by alcohols that form toxic metabolites. Br J Clin Pharmacol 2016; 81:505-15. [PMID: 26551875 DOI: 10.1111/bcp.12824] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 11/02/2015] [Accepted: 11/03/2015] [Indexed: 12/20/2022] Open
Abstract
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.
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Affiliation(s)
- Kenneth McMartin
- Department of Pharmacology, Toxicology & Neuroscience, Louisiana State University Health Sciences Center - Shreveport, 1501 Kings Highway, Shreveport, Louisiana, 71130-3932, USA
| | - Dag Jacobsen
- Department of Acute Medicine, Division of Medicine, Oslo University Hospital, NO-0424, Oslo, Norway
| | - Knut Erik Hovda
- The Norwegian CBRNe Centre of Medicine, Department of Acute Medicine, Division of Medicine, Oslo University Hospital, NO-0424, Oslo, Norway
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Abstract
CONTEXT Methanol, ethylene glycol, diethylene glycol, and propylene glycol intoxications are associated with cellular dysfunction and an increased risk of death. Adverse effects can develop quickly; thus, there is a need for methods for rapidly detecting their presence. OBJECTIVE To examine the value and limitations of present methods to diagnose patients with possible toxic alcohol exposure. METHODS I searched MEDLINE for articles published between 1969 and 2014 using the terms: toxic alcohols, serum osmolality, serum osmol gap, serum anion gap, metabolic acidosis, methanol, ethylene glycol, diethylene glycol, propylene glycol, and fomepizole. Each article was reviewed for additional references. RESULTS The diagnosis of toxic alcohol exposure is often made on the basis of this history and physical findings along with an increase in the serum osmol and anion gaps. However, an increase in the osmol and/or anion gaps is not always present. Definitive detection in blood requires gas or liquid chromatography, laborious and expensive procedures which are not always available. Newer methods including a qualitative colorimetric test for detection of all alcohols or enzymatic tests for a specific alcohol might allow for more rapid diagnosis. CONCLUSIONS Exposure to toxic alcohols is associated with cellular dysfunction and increased risk of death. Treatment, if initiated early, can markedly improve outcome, but present methods of diagnosis including changes in serum osmol and anion gap, and use of gas or liquid chromatography have important limitations. Development of more rapid and effective tests for detection of these intoxications is essential for optimal care of patients.
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Affiliation(s)
- Jeffrey A Kraut
- Medical and Research Services Veterans Administration Greater Los Angeles Healthcare System, UCLA Membrane Biology Laboratory, and Division of Nephrology, Veterans Administration Greater Los Angeles Healthcare System, and David Geffen School of Medicine , Los Angeles , California
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McMartin KE, Sebastian CS, Dies D, Jacobsen D. Kinetics and metabolism of fomepizole in healthy humans. Clin Toxicol (Phila) 2012; 50:375-83. [DOI: 10.3109/15563650.2012.683197] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Mégarbane B. Treatment of patients with ethylene glycol or methanol poisoning: focus on fomepizole. Open Access Emerg Med 2010; 2:67-75. [PMID: 27147840 PMCID: PMC4806829 DOI: 10.2147/oaem.s5346] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Ethylene glycol (EG) and methanol are responsible for life-threatening poisonings. Fomepizole, a potent alcohol dehydrogenase (ADH) inhibitor, is an efficient and safe antidote that prevents or reduces toxic EG and methanol metabolism. Although no study has compared its efficacy with ethanol, fomepizole is recommended as a first-line antidote. Treatment should be started as soon as possible, based on history and initial findings including anion gap metabolic acidosis, while awaiting measurement of alcohol concentration. Administration is easy (15 mg/kg-loading dose, either intravenously or orally, independent of alcohol concentration, followed by intermittent 10 mg/kg-doses every 12 hours until alcohol concentrations are <30 mg/dL). There is no need to monitor fomepizole concentrations. Administered early, fomepizole prevents EG-related renal failure and methanol-related visual and neurological injuries. When administered prior to the onset of significant acidosis or organ injury, fomepizole may obviate the need for hemodialysis. When dialysis is indicated, 1 mg/kg/h-continuous infusion should be provided to compensate for its elimination. Side-effects are rarely serious and with a lower occurrence than ethanol. Fomepizole is contraindicated in case of allergy to pyrazoles. It is both efficacious and safe in the pediatric population, but is not recommended during pregnancy. In conclusion, fomepizole is an effective and safe first-line antidote for EG and methanol intoxications.
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Affiliation(s)
- Bruno Mégarbane
- Réanimation Médicale et Toxicologique, Hôpital Lariboisière and Université Paris-Diderot, Paris, France
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McMartin KE. Antidotes for Alcohol and Glycol Toxicity: Translating Mechanisms Into Treatments. Clin Pharmacol Ther 2010; 88:400-4. [DOI: 10.1038/clpt.2010.157] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Mégarbane B, Houzé P, Baud FJ. Oral fomepizole administration to treat ethylene glycol and methanol poisonings: advantages and limitations. Clin Toxicol (Phila) 2010; 46:1097; author reply 1097-8. [DOI: 10.1080/15563650802310911] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Hovda KE, Jacobsen D. Expert opinion: fomepizole may ameliorate the need for hemodialysis in methanol poisoning. Hum Exp Toxicol 2008; 27:539-46. [PMID: 18829729 DOI: 10.1177/0960327108095992] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Fomepizole is now the antidote of choice in methanol poisoning. The use of fomepizole may also change the indications for hemodialysis in these patients. We have addressed this change in a review of articles on methanol poisonings. Review of the literature (through PubMed) combined with our own experiences from two recent methanol outbreaks in Estonia and Norway. The efficiency of dialysis during fomepizole treatment was reported in only a few reports. One recent study challenged the old indications, suggesting a new approach with delayed or even no hemodialysis. Methanol-poisoned patients on fomepizole treatment may be separated into two categories: 1) The critically ill patient, with severe metabolic acidosis (base deficit >15 mM) and/or visual disturbances should be given buffer, fomepizole and immediate hemodialysis: dialysis removes the toxic anion formate, and assists in correcting the metabolic acidosis, thereby also reducing formate toxicity. The removal of methanol per se is not important in this setting because fomepizole prevents further production of formic acid. 2) The stable patient, with less metabolic acidosis and no visual disturbances, should be given buffer and fomepizole. This treatment allows for the possibility to delay, or even drop, dialysis in this setting, because patients will not develop more clinical features from methanol poisoning when fomepizole and bicarbonate is given in adequate doses. Indications and triage for hemodialysis in methanol poisonings should be modified. Delayed hemodialysis or even no hemodialysis may be an option in selected cases.
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Affiliation(s)
- K E Hovda
- Department of Acute Medicine, Ullevaal University Hospital, Oslo, Norway.
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Bestic M, Blackford M, Reed M. Fomepizole: a critical assessment of current dosing recommendations. J Clin Pharmacol 2008; 49:130-7. [PMID: 19004845 DOI: 10.1177/0091270008327142] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Fomepizole, 4-methylpyrazole (4-MP), is a competitive antagonist of alcohol dehydrogenase with a binding affinity >8000 times that of ethanol. The drug is currently labeled by the United States Food and Drug Administration for the treatment of adult patients with known or suspected ethylene glycol or methanol poisoning. Fomepizole's wide therapeutic dose range and safety profile confer several advantages over standard ethanol therapy for the treatment of toxic alcohol exposures, including the lack of ethanol-associated side effects. Published data and data obtained from the drug's manufacturer implies that the dose escalation after 48 hours is to compensate for fomepizole-induced increased body clearance resulting from autoinduction of the cytochrome P450 (CYP) drug metabolizing enzyme CYP2E1. However, we were unable to identify any evidence of fomepizole's metabolism occurring via CYP2E1 in humans while the data most frequently cited as evidence for induction do not appear to support this claim. Based on this data along with the apparent zero-order kinetics, the current dose increase recommendations may be unnecessary and considering the safety margin described for fomepizole, an extremely conservative constant higher dose administered every 12 hours would appear to assure efficacy and tolerability. Despite the evidence, dose changes should only be implemented after careful clinical trials.
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Affiliation(s)
- Michelle Bestic
- Department of Pharmacology and Critical Care, Case Western Reserve University School of Medicine, Cleveland, OH, USA
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