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Slavica V, Dubravko B, Milan J. Acute organophosphate poisoning: 17 years of experience of the National Poison Control Center in Serbia. Toxicology 2018; 409:73-79. [PMID: 30055297 DOI: 10.1016/j.tox.2018.07.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 07/05/2018] [Accepted: 07/18/2018] [Indexed: 11/30/2022]
Abstract
Based on human toxicity studies, by appropriate regulatory decisions, the number of organophosphates (OP) on Serbian market has reduced significantly over the last two decades, followed by a gradual decrease in the number of poisonings by organophoshates, treated at the National Poison Control Centre (NPCC). METHODOLOGY The aim of this retrospective study is to present data regarding the clinical management of poisoning with OP pesticides at the NPCC, that we collected during the 17 years period (1998-2014). RESULTS In the period 1998-2014, about 17.250 patients were hospitalized at the NPCC, there were around 14.000 patients treated for poisoning by various toxic agents, and among them 410 cases (3%) due to poisoning with OP pesticides. In this period, 92% of OPI poisonings treated in the NPCC were suicidal by intention, while only 8% were due to accidental ingestion or inhalation. The most common clinical signs of poisoning in patients exposed to anticholinesterase pesticides, observed at Clinic of Toxicology of the NPCC were miosis (63.4%), bronchorrhoea (51.9%), vomiting and diarrhea (44.8%), hypotension (19.5%). Acute respiratory insufficiency was registered in 81 (19.7%) and acute cardiocirculatory failure in 16 (3.9%) patients. There were about 25% of most severely poisoned patients. Besides general supportive measures (decontamination, respiratory support), specific pharmacological treatment (atropine, oxime, diazepam) was applied. The highest total administered dose of atropine at NPCC was 6400 mg. However, the most patients received total doses of atropine up to 500 mg (32%). CONCLUSION Acute poisoning with OP pesticides is not frequent in Serbia, however, it represents important clinical feature due to severity, possible complications and their impact on duration and costs of hospitalization. Initial treatment involves prevention of further absorption and provision of supportive care, followed by administration of specific antidotes. According to its role, the National Poison Control Centre in Belgrade, in addition to treatment of acute poisonings, continuously performs toxicovigilance, i.e. the identification, investigation and evaluation of various toxic risks in the community in order to undertake adequate and timely procedures. Permanent efforts are being made in order to reduce availability and to improve control measures for pesticides marketing.
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Affiliation(s)
- Vučinić Slavica
- National Poison Control Center, Military Medical Academy, Medical Faculty University of Defense, Crnotravska 17, 11000 Belgrade, Serbia.
| | - Bokonjić Dubravko
- National Poison Control Center, Military Medical Academy, Medical Faculty University of Defense, Crnotravska 17, 11000 Belgrade, Serbia
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Ivosevic A, Miletic N, Vulovic M, Vujkovic Z, Bursac SN, Cetkovic SS, Skrbic R, Stojiljkovic MP. Mechanism and Clinical Importance of Respiratory Failure Induced by Anticholinesterases. SERBIAN JOURNAL OF EXPERIMENTAL AND CLINICAL RESEARCH 2017. [DOI: 10.1515/sjecr-2016-0047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Respiratory failure is the predominant cause of death in humans and animals poisoned with anticholinesterases. Organophosphorus and carbamate anticholinesterases inhibit acetylcholinesterase irreversibly and reversibly, respectively. Some of them contain a quaternary atom that makes them lipophobic, limiting their action at the periphery, i.e. outside the central nervous system. They impair respiratory function primarily by inducing a desensitization block of nicotinic receptors in the neuromuscular synapse. Lipophilic anticholinesterases inhibit the acetylcholinesterase both in the brain and in other tissues, including respiratory muscles. Their doses needed for cessation of central respiratory drive are significantly less than doses needed for paralysis of the neuromuscular transmission. Antagonist of muscarinic receptors atropine blocks both the central and peripheral muscarinic receptors and effectively antagonizes the central respiratory depression produced by anticholinesterases. To manage the peripheral nicotinic receptor hyperstimulation phenomena, oximes as acetylcholinesterase reactivators are used. Addition of diazepam is useful for treatment of seizures, since they are cholinergic only in their initial phase and can contribute to the occurrence of central respiratory depression. Possible involvement of central nicotinic receptors as well as the other neurotransmitter systems – glutamatergic, opioidergic – necessitates further research of additional antidotes.
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Affiliation(s)
- Anita Ivosevic
- Department of Internal Medicine, Faculty of Medical Sciences , University of Kragujevac , Kragujevac , Serbia
| | - Natasa Miletic
- Medical Faculty , University of East Sarajevo , Foča , Republic of Srpska, Bosnia & Herzegovina
| | - Maja Vulovic
- Department of Anatomy and Forensic Medicine, Faculty of Medical Sciences , University of Kragujevac , Kragujevac , Serbia
| | - Zoran Vujkovic
- Neurology Clinic, University Clinical Centre of Republic of Srpska, Medical Faculty , University of Banja Luka , Banja Luka , Republic of Srpska, Bosnia & Herzegovina
| | - Snjezana Novakovic Bursac
- Institute for Physical Medicine and Rehabilitation „Dr Miroslav Zotovic“ , Banja Luka , Republic of Srpska, Bosnia & Herzegovina
| | | | - Ranko Skrbic
- Department of Pharmacology, Toxicology & Clinical Pharmacology, Medical Faculty , University of Banja Luka , Banja Luka , Republic of Srpska, Bosnia & Herzegovina
| | - Milos P. Stojiljkovic
- Medical Faculty , University of East Sarajevo , Foča , Republic of Srpska, Bosnia & Herzegovina
- Department of Pharmacology, Toxicology & Clinical Pharmacology, Medical Faculty , University of Banja Luka , Banja Luka , Republic of Srpska, Bosnia & Herzegovina
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John H, Blum MM. Review of UV spectroscopic, chromatographic, and electrophoretic methods for the cholinesterase reactivating antidote pralidoxime (2-PAM). Drug Test Anal 2011; 4:179-93. [DOI: 10.1002/dta.327] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 06/21/2011] [Accepted: 06/21/2011] [Indexed: 11/06/2022]
Affiliation(s)
- Harald John
- Bundeswehr Institute of Pharmacology and Toxicology; Munich; Germany
| | - Marc-Michael Blum
- Los Alamos National Laboratory, Bioscience Division; Los Alamos; NM; USA (LA-UR 11-04236)
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Piplani S, Handa A, Aggrawal R, Gupta BK, Mishra SC, Roy P, Gupta ID. ORGANOPHOSPHOROUS POISONING WITH INTERMEDIATE SYNDROME. Med J Armed Forces India 2011; 58:81-3. [PMID: 27365668 DOI: 10.1016/s0377-1237(02)80022-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Affiliation(s)
- S Piplani
- Classified Specialist (Medicine), Cancer Institute, Chennai (on study leave)
| | - A Handa
- Graded Specialist (Medicine), Command Hospital (Air Force), Bangalore
| | - R Aggrawal
- Classified Specialist (Anaesthesia), 7 Air Force Hospital, Kanpur
| | - B K Gupta
- Graded Specialist (Anaesthesia), 5 Air Force Hospital C/O 99 APO
| | - S C Mishra
- Graded Specialist (Medicine), 5 Air Force Hospital C/O 99 APO
| | - P Roy
- Graded Specialist (Pathology), 5 Air Force Hospital C/O 99 APO
| | - I D Gupta
- Commandant, Command Hospital (Central Command), Lucknow
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Jun D, Musilova L, Musilek K, Kuca K. In vitro ability of currently available oximes to reactivate organophosphate pesticide-inhibited human acetylcholinesterase and butyrylcholinesterase. Int J Mol Sci 2011; 12:2077-87. [PMID: 21673941 PMCID: PMC3111652 DOI: 10.3390/ijms12032077] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Accepted: 03/09/2011] [Indexed: 11/16/2022] Open
Abstract
We have in vitro tested the ability of common, commercially available, cholinesterase reactivators (pralidoxime, obidoxime, methoxime, trimedoxime and HI-6) to reactivate human acetylcholinesterase (AChE), inhibited by five structurally different organophosphate pesticides and inhibitors (paraoxon, dichlorvos, DFP, leptophos-oxon and methamidophos). We also tested reactivation of human butyrylcholinesterase (BChE) with the aim of finding a potent oxime, suitable to serve as a “pseudocatalytic” bioscavenger in combination with this enzyme. Such a combination could allow an increase of prophylactic and therapeutic efficacy of the administered enzyme. According to our results, the best broad-spectrum AChE reactivators were trimedoxime and obidoxime in the case of paraoxon, leptophos-oxon, and methamidophos-inhibited AChE. Methamidophos and leptophos-oxon were quite easily reactivatable by all tested reactivators. In the case of methamidophos-inhibited AChE, the lower oxime concentration (10−5 M) had higher reactivation ability than the 10−4 M concentration. Therefore, we evaluated the reactivation ability of obidoxime in a concentration range of 10−3–10−7 M. The reactivation of methamidophos-inhibited AChE with different obidoxime concentrations resulted in a bell shaped curve with maximum reactivation at 10−5 M. In the case of BChE, no reactivator exceeded 15% reactivation ability and therefore none of the oximes can be recommended as a candidate for “pseudocatalytic” bioscavengers with BChE.
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Affiliation(s)
- Daniel Jun
- Center of Advanced Studies, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, Hradec Kralove, 500 01, Czech Republic
- Department of Water Resources and Environmental Modeling, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamycka 129, Praha 6—Suchdol, 16521, Czech Republic
- University Hospital Hradec Kralove, Sokolska 581, Hradec Kralove, 50005, Czech Republic
- Authors to whom correspondence should be addressed; E-Mails: (D.J.); (K.K.); Tel.: +420-973-255-193; Fax: +420-495-518-094
| | - Lucie Musilova
- Hospital Pharmacy, University Hospital Hradec Kralove, Sokolska 581, Hradec Kralove, 500 05, Czech Republic; E-Mail:
- Department of Biochemical Sciences, Charles University in Prague, Faculty of Pharmacy in Hradec Kralove, Heyrovskeho 1203, Hradec Kralove, 50005, Czech Republic
| | - Kamil Musilek
- Department of Toxicology, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, Hradec Kralove, 50001, Czech Republic; E-Mail:
| | - Kamil Kuca
- Center of Advanced Studies, Faculty of Military Health Sciences, University of Defence, Trebesska 1575, Hradec Kralove, 500 01, Czech Republic
- Authors to whom correspondence should be addressed; E-Mails: (D.J.); (K.K.); Tel.: +420-973-255-193; Fax: +420-495-518-094
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7
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Abstract
BACKGROUND Acute organophosphorus pesticide poisoning causes tens of thousands of deaths each year across the developing world. Standard treatment involves administration of intravenous atropine and oxime to reactivate inhibited acetylcholinesterase. The clinical usefulness of oximes, such as pralidoxime and obidoxime, has been challenged over the past 20 years by physicians in many parts of the world. OBJECTIVES To quantify the effectiveness and safety of the administration of oximes in acute organophosphorus pesticide-poisoned patients. SEARCH STRATEGY We searched both English and Chinese databases: Cochrane Injuries Group Specialised Register, Cochrane Central Register of Controlled Trials (The Cochrane Library), MEDLINE (Ovid SP), EMBASE (Ovid SP), ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED), ISI Web of Science: Conference Proceedings Citation Index-Science (CPCI-S) and the Chinese language databases CNKI and WANGFANG. All searches were run in September 2009. SELECTION CRITERIA Articles that could possibly be RCTs were retrieved to determine if they were randomised. DATA COLLECTION AND ANALYSIS The published methodology of three RCTs was not clear. We contacted the principal authors of these, but did not obtain further information. MAIN RESULTS Seven pralidoxime RCTs were found. Three RCTs including 366 patients studied pralidoxime vs placebo and four RCTs including 479 patients compared two or more different doses. These trials found quite disparate results with treatment effects ranging from benefit to harm. However, many studies did not take into account several issues important for outcomes. In particular, baseline characteristics were not balanced, oxime doses varied widely, there were substantial delays to treatment, and the type of organophosphate was not taken into account. Only one RCT compared the World Health Organization (WHO) recommended doses with placebo. This trial showed no clinical benefits and a trend towards harm in all sub-groups, despite clear evidence that these doses reactivated acetylcholinesterase in the blood. AUTHORS' CONCLUSIONS Current evidence is insufficient to indicate whether oximes are harmful or beneficial. The WHO recommended regimen (30 mg/kg pralidoxime chloride bolus followed by 8 mg/kg/hr infusion) is not supported. Further RCTs are required to examine other strategies and regimens. There are many theoretical and practical reasons why oximes may not be useful, particularly for late presentations of dimethyl OP and those with a large excess of OP that simply re-inhibits reactivated enzymes. Future studies should screen for patient sub-groups that may benefit and may need flexible dosing strategies as clinical effectiveness and doses may depend on the type of OP.
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Affiliation(s)
- Nick A Buckley
- Professorial Medicine Unit, POWH Clinical School, University of NSW, South Wing, Edmund Blackett building, Prince of Wales Hospital, Randwick, NSW, Australia, 2031
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Ekström F, Hörnberg A, Artursson E, Hammarström LG, Schneider G, Pang YP. Structure of HI-6*sarin-acetylcholinesterase determined by X-ray crystallography and molecular dynamics simulation: reactivator mechanism and design. PLoS One 2009; 4:e5957. [PMID: 19536291 PMCID: PMC2693926 DOI: 10.1371/journal.pone.0005957] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Accepted: 04/24/2009] [Indexed: 11/18/2022] Open
Abstract
Organophosphonates such as isopropyl metylphosphonofluoridate (sarin) are extremely toxic as they phosphonylate the catalytic serine residue of acetylcholinesterase (AChE), an enzyme essential to humans and other species. Design of effective AChE reactivators as antidotes to various organophosphonates requires information on how the reactivators interact with the phosphonylated AChEs. However, such information has not been available hitherto because of three main challenges. First, reactivators are generally flexible in order to change from the ground state to the transition state for reactivation; this flexibility discourages determination of crystal structures of AChE in complex with effective reactivators that are intrinsically disordered. Second, reactivation occurs upon binding of a reactivator to the phosphonylated AChE. Third, the phosphorous conjugate can develop resistance to reactivation. We have identified crystallographic conditions that led to the determination of a crystal structure of the sarin(nonaged)-conjugated mouse AChE in complex with [(E)-[1-[(4-carbamoylpyridin-1-ium-1-yl)methoxymethyl]pyridin-2-ylidene]methyl]-oxoazanium dichloride (HI-6) at a resolution of 2.2 A. In this structure, the carboxyamino-pyridinium ring of HI-6 is sandwiched by Tyr124 and Trp286, however, the oxime-pyridinium ring is disordered. By combining crystallography with microsecond molecular dynamics simulation, we determined the oxime-pyridinium ring structure, which shows that the oxime group of HI-6 can form a hydrogen-bond network to the sarin isopropyl ether oxygen, and a water molecule is able to form a hydrogen bond to the catalytic histidine residue and subsequently deprotonates the oxime for reactivation. These results offer insights into the reactivation mechanism of HI-6 and design of better reactivators.
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Affiliation(s)
- Fredrik Ekström
- Swedish Defence Research Agency, CBRN Defence and Security, Umeå, Sweden
| | - Andreas Hörnberg
- Swedish Defence Research Agency, CBRN Defence and Security, Umeå, Sweden
| | - Elisabet Artursson
- Swedish Defence Research Agency, CBRN Defence and Security, Umeå, Sweden
| | | | - Gunter Schneider
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Yuan-Ping Pang
- Computer-Aided Molecular Design Laboratory, Mayo Clinic, Rochester, Minnesota, United States of America
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10
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Stephen S, Laura J, Gregory K, Henry F. The Pharmacokinetics of Continuous Infusion Pralidoxime in Children with Organophosphate Poisoning. ACTA ACUST UNITED AC 2008. [DOI: 10.3109/15563659809028048] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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11
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Abstract
The organic phosphorous compounds (OPC) include both the military grade nerve agents and the organic phosphorous pesticides. The major mechanism of OPC toxicity is through inhibition of acetylcholinesterase in neuronal synapses leading to excess acetylcholine and overstimulation of target organs. Signs and symptoms depend on the affinity of the OPC for muscarinic versus nicotinic receptors, and are likely to include both. Muscarinic symptoms may include diarrhea, urination, bronchospasm, bronchorrhea, emesis, and salivation. Nicotinic symptoms such as paralysis and fasciculations may also occur. Central nervous system toxicity may include seizures, altered mental status, and apnea, and require prompt intervention. Treatment includes early airway and ventilatory support as well as antidotal therapy with atropine, pralidoxime, and diazepam. Goals of therapy include prevention and rapid treatment of hypoxia and seizures, as these are linked to patient outcome.
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Affiliation(s)
- Claudia L Barthold
- Georgia Poison Center, Hughes Spalding Children's Hospital, Grady Health System, 80 Jesse Hill Jr. Drive SE, Atlanta, GA 30303-3801, USA.
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Rao CHS, Venkateswarlu V, Surender T, Eddleston M, Buckley NA. Pesticide poisoning in south India: opportunities for prevention and improved medical management. Trop Med Int Health 2005; 10:581-8. [PMID: 15941422 PMCID: PMC1762001 DOI: 10.1111/j.1365-3156.2005.01412.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Warangal district in Andhra Pradesh, southern India, records >1000 pesticide poisoning cases each year and hundreds of deaths. We aimed to describe their frequency and distribution, and to assess quality of management and subsequent outcomes from pesticide poisoning in one large hospital in the district. METHODS We reviewed data on all patients admitted with pesticide poisoning to a district government hospital for the years 1997 to 2002. For 2002, details of the particular pesticide ingested and management were abstracted from the medical files. FINDINGS During these 6 years, 8040 patients were admitted to the hospital with pesticide poisoning. The overall case fatality ratio was 22.6%. More detailed data from 2002 revealed that two-thirds of the patients were <30 years old, 57% were male and 96% had intentionally poisoned themselves. Two compounds, monocrotophos and endosulfan, accounted for the majority of deaths with known pesticides in 2002. Low fixed-dose regimens were used in the majority of cases for the most commonly used antidotes (atropine and pralidoxime). Inappropriate antidotes were also used in some patients. CONCLUSIONS It is likely that these findings reflect the situation in many rural hospitals of the Asia Pacific region. Even without an increase in resources, there appear to be significant opportunities for reducing mortality by better medical management and further restrictions on the most toxic pesticides.
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Affiliation(s)
- CH Srinivas Rao
- Senior Research Fellow, University College of Pharmaceutical Sciences, Kakatiya University, Warangal, Andhra Pradesh, India.
| | - V Venkateswarlu
- Associate Professor, University College of Pharmaceutical Sciences, Kakatiya University, Warangal, Andhra Pradesh, India
| | - T Surender
- Professor of Medicine, MGM Hospital, Warangal, Andhra Pradesh, India
| | - Michael Eddleston
- Wellcome Trust Career Development Fellow, Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK, and South Asian Clinical Toxicology Research Collaboration, Department of Clinical Medicine, University of Colombo, Sri Lanka.
| | - Nick A Buckley
- Director and Associate Professor, Department of Clinical Pharmacology & Toxicology, Canberra Clinical School, ACT, Australia, and South Asian Clinical Toxicology Research Collaboration, Sri Lanka.
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Abstract
BACKGROUND Acute organophosphorus pesticide poisoning causes tens of thousands of deaths each year across the developing world. Standard treatment involves administration of intravenous atropine and oxime to counter acetylcholinesterase inhibition at the synapse. The usefulness of oximes, such as pralidoxime and obidoxime, has been challenged over the past 20 years by physicians in many parts of the world, who have failed to see benefit in their clinical practice. OBJECTIVES To find the clinical trial evidence for oximes producing clinical benefit in acute organophosphorus pesticide-poisoned patients. SEARCH STRATEGY We carried out a systematic search to find randomised clinical trials (RCTs) of oximes in acute organophosphorus pesticide poisoning, using MEDLINE, EMBASE and Cochrane databases. All articles with the text words 'organophosphate' or 'oxime' together with 'poisoning' or 'overdose' were examined. (Search last updated November 2003.) SELECTION CRITERIA Articles that could possibly be randomised clinical trials were retrieved to determine if this was the case. DATA COLLECTION AND ANALYSIS The published methodology of the possible RCTs located is not clear. One was found in abstract form only and two other published trials also had many gaps in the published methodology. We have attempted to contact the principal authors of all three trials but have been unable to obtain further information. MAIN RESULTS Two RCTs have been published, involving 182 patients treated with pralidoxime. These trials did not find benefit. However, the studies did not take into account a number of issues important for outcome and the methodology is unclear. Therefore, a generalised statement on effectiveness cannot be supported by the published results. In particular, characteristics at baseline were not evenly balanced, the dose of oxime was much lower than recommended in guidelines, there were substantial delays to treatment, and the type of organophosphate was not taken into account. The abstract of the third trial, a small possible RCT, is uninterpretable without further data. AUTHORS' CONCLUSIONS Current evidence is insufficient to indicate whether oximes are harmful or beneficial in the management of acute organophosphorus pesticide poisoning. A much larger RCT is required to compare the World Health Organization recommended pralidoxime regimen (>30 mg/kg bolus followed by >8 mg/kg/hr infusion) with placebo. There are many theoretical and practical reasons why oximes may not be useful to patients with overwhelming self-poisoning. Such a study will need to be designed with pre-defined sub-group analysis to allow identification of patient sub-groups that may benefit from oximes.
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Affiliation(s)
- N A Buckley
- Dept. of Clinical Pharmacology, Australian National University Medical School, Canberra Hospital, PO Box 11, , Woden ACT 2606, Australia.
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Houzé P, Borron SW, Scherninski F, Bousquet B, Gourmel B, Baud F. Measurement of serum pralidoxime methylsulfate (Contrathion®) by high-performance liquid chromatography with electrochemical detection. J Chromatogr B Analyt Technol Biomed Life Sci 2005; 814:149-54. [PMID: 15607719 DOI: 10.1016/j.jchromb.2004.10.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2004] [Accepted: 10/06/2004] [Indexed: 11/17/2022]
Abstract
Pralidoxime methylsulfate (Contrathion) is widely used to treat organophosphate poisoning. Despite animal and human studies, the usefulness of Contrathion therapy remains a matter of debate. Therapeutic dosage regimens need to be clarified and availability of a reliable method for plasma pralidoxime quantification would be helpful in this process. We here describe a high-performance liquid chromatography technique with electrochemical detection to measure pralidoxime concentrations in human serum using guanosine as an internal standard. The assay was linear between 0.25 and 50 microg mL(-1) with a quantification limit of 0.2 microg mL(-1). The analytical precision was satisfactory, with variation coefficients lower 10%. This assay was applied to the analysis of a serum from an organophosphorate poisoned patient and treated by Contrathion infusions (100 and 200 mg h(-1)) after a loading dose (400 mg).
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Affiliation(s)
- Pascal Houzé
- Laboratoire de Biochmie A, Hôpital Saint Louis, 1 Avenue Claude Vellefaux, 75010 Paris, France.
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15
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Abstract
The number of intoxications with organophosphorus pesticides (OPs) is estimated at some 3,000,000 per year, and the number of deaths and casualties some 300,000 per year. OPs act primarily by inhibiting acetylcholinesterase (AChE), thereby allowing acetylcholine to accumulate at cholinergic synapses, disturbing transmission at parasympathetic nerve endings, sympathetic ganglia, neuromuscular endplates and certain CNS regions. Atropine is the mainstay of treatment of effects mediated by muscarine sensitive receptors; however, atropine is ineffective at the nicotine sensitive synapses. At both receptor types, reactivation of inhibited AChE may improve the clinical picture. The value of oximes, however, is still a matter of controversy. Enthusiastic reports of outstanding antidotal effectiveness, substantiated by laboratory findings of reactivated AChE and improved neuromuscular transmission, contrast with many reports of disappointing results. In vitro studies with human erythrocyte AChE, which is derived from the same single gene as synaptic AChE, revealed marked differences in the potency and efficacy of pralidoxime, obidoxime, HI 6 and HLö 7, the latter two oximes being considered particularly effective in nerve agent poisoning. Moreover, remarkable species differences in the susceptibility to oximes were revealed, requiring caution when animal data are extrapolated to humans. These studies impressively demonstrated that any generalisation regarding an effective oxime concentration is inappropriate. Hence, the 4 mg/L concept should be dismissed. To antagonise the toxic effects of the most frequently used OPs, pralidoxime plasma concentrations of around 80 mumol/L (13.8 mg/L pralidoxime chloride) should be attained while obidoxime plasma concentrations of 10 mumol/L (3.6 mg/L obidoxime chloride) may be sufficient. These concentrations should be maintained as long as circulating poison is expected to be present, which may require oxime therapy for up to 10 days. Various dosage regimens exist to reach this goal. The most appropriate consists of a bolus short infusion followed by a maintenance dosage. For pralidoxime chloride, a 1 g bolus over 30 minutes followed by an infusion of 0.5 g/h appears appropriate to maintain the target concentrtion of about 13 mg/L (70 kg person). For obidoxime chloride, the appropriate dosage is a 0.25 g bolus followed by an infusion of 0.75 g/24 h. These concentrations are well tolerated and keep a good portion of AChE in the active state, thereby retarding the AChE aging rate. AChE aging is particularly rapid with dimethyl phosphoryl compounds and may thwart the effective reactivation by oximes, particularly in suicidal poisoning with excessive doses. In contrast, patients with diethyl OP poisoning may particularly benefit from oxime therapy, even if no improvement is seen during the first days when the poison load is high. The low propensity to aging with diethyl OP poisoning may allow reactivation after several days, when the poison concentration drops. Rigorous testing of the benefits of oximes is only possible in randomised controlled trials with clear stratification according to the class of pesticides involved, time elapsed between exposure and treatment and severity of cholinergic symptoms on admission.
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Affiliation(s)
- Peter Eyer
- Walther-Straub-Institute of Pharmacology and Toxicology, Ludwig-Maximilians-University, Munich, Germany.
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16
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Abstract
Nerve agents are perhaps the most feared of potential agents of chemical attack. The authors review the history, physical characteristics, pharmacology, clinical effects, and treatment of these agents.
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Affiliation(s)
- Sage W Wiener
- NYC Poison Control Center, Bellevue Hospital Center, New York University Medical Center, and New York University School of Medicine, New York, NY 10016, USA.
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17
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Leikin JB, Thomas RG, Walter FG, Klein R, Meislin HW. A review of nerve agent exposure for the critical care physician. Crit Care Med 2002; 30:2346-54. [PMID: 12394966 DOI: 10.1097/00003246-200210000-00026] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Nerve agents are discussed. The article discusses their properties, routes of exposure, toxicodynamics, targets of toxicity, and treatment. It is concluded that a focused organized approach to the treatment of nerve agents is key to its successful management.
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Affiliation(s)
- Jerrold B Leikin
- Evanston Northwestern Healthare OMEGA, Glenbrook Hospital, Glenview, IL, USA.
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Eddleston M, Szinicz L, Eyer P, Buckley N. Oximes in acute organophosphorus pesticide poisoning: a systematic review of clinical trials. QJM 2002; 95:275-83. [PMID: 11978898 PMCID: PMC1475922 DOI: 10.1093/qjmed/95.5.275] [Citation(s) in RCA: 190] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Acute organophosphorus (OP) pesticide poisoning is widespread in the developing world. Standard treatment involves the administration of intravenous atropine and an oxime to counter acetylcholinesterase inhibition at the synapse, but the usefulness of oximes is uncertain. AIM To assess the evidence on the use of oximes in OP poisoning. DESIGN Systematic review. METHODS We searched Medline, Embase, and Cochrane databases (last check 01/02/02) for 'organophosphate' or 'oxime' together with 'poisoning' or 'overdose'. We cross-referenced from other articles, and contacted experts to identify unpublished studies. A Web search engine [www.google.com] was also used, with the keywords 'organophosphate', 'oxime', and 'trial' (last check 01/02/02). RESULTS We found two randomized controlled trials (RCTs) involving 182 patients treated with pralidoxime. The RCTs found no benefit with pralidoxime, and have been used to argue that pralidoxime should not be used in OP poisoning. DISCUSSION The RCT authors must be congratulated for attempting important studies in a difficult environment. However, their studies did not take into account recently clarified issues regarding outcome, and their methodology is unclear. A generalized statement that pralidoxime should not be used in OP poisoning is not supported by the published results. Oximes may well be irrelevant in the overwhelming self-poisoning typical of the tropics, but a large RCT comparing the current WHO-recommended pralidoxime regimen (>30 mg/kg bolus followed by >8 mg/kg/h infusion) with placebo is needed for a definitive answer. Such a study should be designed to identify any patient subgroups that might benefit from oximes.
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Affiliation(s)
- M Eddleston
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, UK.
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Choi PT, Quinonez LG, Cook DJ, Baxter F, Whitehead L. The use of glycopyrrolate in a case of intermediate syndrome following acute organophosphate poisoning. Can J Anaesth 1998; 45:337-40. [PMID: 9597208 DOI: 10.1007/bf03012025] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
PURPOSE This report describes a case of organophosphate intoxication refractory to atropine in which glycopyrrolate was used to reduce cholinergic symptoms, and describes the development of intermediate syndrome, an uncommon subacute complication of organophosphate poisoning. CLINICAL FEATURES A 44-yr-old woman presented in cholinergic crisis following malathion ingestion. Treatment was initiated with atropine and pralidoxime. Despite clinical signs of adequate atropinisation, the patient continued to have profuse bronchorrhoea, which resolved with glycopyrrolate. During her course in the intensive care unit, she displayed a subacute deterioration in neuromuscular and mental status with decrement-increment phenomenon on electromyography consistent with intermediate syndrome. The patient eventually made a complete recovery. CONCLUSION This case report describes the successful use of glycopyrrolate in organophosphate intoxication and the development of the intermediate syndrome, characterised by onset of weakness of neck flexors, proximal limb muscles, and respiratory muscles within one to four days after poisoning. Recognition of the syndrome is important in light of the potential for respiratory depression requiring ventilatory support.
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Affiliation(s)
- P T Choi
- Department of Anaesthesia, McMaster University, Ontario, Canada.
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Tush GM, Anstead MI. Pralidoxime continuous infusion in the treatment of organophosphate poisoning. Ann Pharmacother 1997; 31:441-4. [PMID: 9101007 DOI: 10.1177/106002809703100411] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
OBJECTIVE To report a case of organophosphate poisoning treated with a continuous infusion of pralidoxime chloride. CASE SUMMARY A 27-year-old white man presented with extreme agitation, muscle weakness and fasciculations, and respiratory failure after ingesting an organophosphate pesticide (Dursban, active ingredients chlorpyrifos and xylene) as a suicide attempt. Atropine sulfate and pralidoxime chloride were administered intermittently, but the patient continued to be extremely agitated and have muscle fasciculations. Subsequently, a continuous intravenous infusion of pralidoxime (8 mg/mL concentration) at 500 mg/h was initiated to help control breakthrough nicotinic symptoms. Therapy with atropine and pralidoxime was continued for approximately 72 hours. Therapy was discontinued due to the predominance of anticholinergic symptoms and the patient's increased awareness. DISCUSSION Severe organophosphate poisoning with nicotinic and/or central manifestations should be treated with pralidoxime in addition to atropine. The rationale supporting the use of pralidoxime as a continuous infusion in this case includes: (1) slow absorption of organophosphate compounds following exposure to large quantities, (2) unknown quantity ingested, (3) delayed nicotinic effects from redistribution of lipid-soluble organophosphate and metabolic activation of phosphorothioates such as chlorpyrifos, and (4) intensive care monitoring. There is limited documentation in the literature of continuous infusions of pralidoxime used to treat organophosphate poisoning and the stability of the admixture is unknown. CONCLUSIONS A continuous pralidoxime infusion successfully managed the prolonged nicotinic symptoms seen after ingestion of an organophosphate. A continuous infusion of pralidoxime may be particularly useful in cases of organophosphate poisoning when the extent of chemical exposure or quantity of chemical ingested is unknown but potentially toxic and the therapy must be symptomatically managed.
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Affiliation(s)
- G M Tush
- Department of Pharmacy and Pharmaceutics, Medical College of Virginia/VCU, Richmond, USA
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Zoppellari R, Borron SW, Chieregato A, Targa L, Scaroni I, Zatelli R. Isofenphos poisoning: prolonged intoxication after intramuscular injection. JOURNAL OF TOXICOLOGY. CLINICAL TOXICOLOGY 1997; 35:401-4. [PMID: 9204101 DOI: 10.3109/15563659709043373] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We report a unique case of attempted suicide by intramuscular injection of the organophosphate isofenphos which resulted in a muscarinic and nicotinic syndrome lasting 15 days and requiring prolonged mechanical ventilation and hospitalization. The patient, who demonstrated no signs of delayed polyneuropathy on hospital day 25, subsequently died of pneumonia. Toxicological investigations showed isofenphos plasma decay and confirmed the intramuscular route of poisoning. We believe continuous isofenphos absorption resulted in the prolonged intoxication observed in this patient.
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Affiliation(s)
- R Zoppellari
- 1 Servizio di Anestesia e Rianimazione, Azienda Ospedaliera Arcispedale S. Anna, Ferrara, Italy
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Medicis JJ, Stork CM, Howland MA, Hoffman RS, Goldfrank LR. Pharmacokinetics following a loading plus a continuous infusion of pralidoxime compared with the traditional short infusion regimen in human volunteers. JOURNAL OF TOXICOLOGY. CLINICAL TOXICOLOGY 1996; 34:289-95. [PMID: 8667466 DOI: 10.3109/15563659609013791] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Many authors currently recommend infusing the adult dose (1 g) of pralidoxime over a 15-30 minute period. When administered in this manner, computer simulations predict that plasma pralidoxime concentrations will fall below 4 mg/L as early as one and one half hours after administration. The objective of this study was to assess whether a loading dose followed by a continuous infusion would maintain therapeutic levels longer than the traditional short infusion regimen of pralidoxime if the same total dose was administered. METHODS Utilizing a randomized, crossover design, healthy volunteers were administered either 16 mg/kg of pralidoxime intravenous over 30 minutes or 4 mg/kg of pralidoxime intravenous over 15 minutes followed by 3.2 mg/kg/h for 3.75 h (for a total dose of 16 mg/kg). Pralidoxime levels were obtained at 0, 10, 20, 30, 60, 120, 180, 240, 300, and 390 minutes and patients were observed for vital sign changes and adverse effects. RESULTS Seven subjects completed both arms of the study. One subject's data were excluded from pharmacokinetic analysis due to aberrant plasma pralidoxime analysis. The loading dose followed by the continuous infusion maintained therapeutic levels for 257.3 +/- 50.5 minutes whereas the short infusion maintained therapeutic levels for 118.1 +/- 52.1 (p < 0.001). Adverse effects were encountered during the short infusion regimen which did not occur during the continuous infusion. Dizziness or blurred vision occurred in all subjects during the short infusion regimen. Additionally, statistically significant increases in diastolic blood pressure occurred during the short infusion regimen. CONCLUSIONS The results of this study indicate that a loading dose followed by a continuous infusion of pralidoxime maintains therapeutic concentrations for a longer period of time than the currently recommended short infusion regimen in healthy volunteers.
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Affiliation(s)
- J J Medicis
- University Hospital, State University of New York, Health Science Center at Syracuse 13210, USA
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Kirk MA, Cisek J, Rose SR. Emergency Department Response to Hazardous Materials Incidents. Emerg Med Clin North Am 1994. [DOI: 10.1016/s0733-8627(20)30438-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Buckley NA, Dawson AH, Whyte IM. Organophosphate poisoning: peripheral vascular resistance--a measure of adequate atropinization. JOURNAL OF TOXICOLOGY. CLINICAL TOXICOLOGY 1994; 32:61-8. [PMID: 8308950 DOI: 10.3109/15563659409000431] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We report severe organophosphate poisoning complicated by hypotension and ischemic sequelae in two patients with pre-existing vascular disease. Both patients had a low total peripheral resistance and high cardiac output that were significantly reversed by doses of atropine in excess of those required to control other muscarinic symptoms. Cerebral infarcts and gangrene requiring a below knee amputation were complications of the poisonings. It is proposed that the ischemic complications are due to paradoxical vasoconstriction by acetylcholine at sites of endothelial injury. One patient, who had taken fenthion, also had a significantly delayed peak and prolonged, 2-3 week, systemic toxicity. We propose that stability of the plasma cholinesterase at 6 to 8 h after temporarily suspending oxime provides a rapid guide to the duration of therapy, especially in patients whose complications make clinical assessment difficult.
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Affiliation(s)
- N A Buckley
- Department of Clinical Pharmacology & Toxicology Mater Misericordiae Hospital, Warath, Australia
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Farrar HC, Wells TG, Kearns GL. Use of continuous infusion of pralidoxime for treatment of organophosphate poisoning in children. J Pediatr 1990; 116:658-61. [PMID: 2319410 DOI: 10.1016/s0022-3476(05)81622-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- H C Farrar
- Department of Pediatrics, University of Arkansas for Medical Science, Little Rock
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Minton NA, Murray VS. A review of organophosphate poisoning. MEDICAL TOXICOLOGY AND ADVERSE DRUG EXPERIENCE 1988; 3:350-75. [PMID: 3057326 DOI: 10.1007/bf03259890] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Many organophosphate compounds are pesticides widely used for the control of insect vectors. They are not ideal agents because they lack target vector selectivity, and have caused severe toxicity and even death in humans and domestic animals. Their toxicity has been recognised since the 1930s, when they were also developed for use as chemical warfare agents. The mechanism of action of organophosphates has been determined in some depth; the understanding of the toxic effects resulting from the inhibition of cholinesterase activity, causing accumulation of acetylcholine at nerve endings has played a major part in providing a rationale for specific antidote treatment using atropine and oximes. However, the most suitable oxime for reactivation of cholinesterases has still not been established with certainty, although pralidoxime is widely recommended. Chronic toxicity, particularly the neuropathic effects, merits further study because it contributes substantially to the long term morbidity in cases of severe acute, or chronic, exposure. Prevention of potentially toxic organophosphate exposure, particularly amongst employees in industries manufacturing or using the compounds and in the most susceptible groups of the population, such as the young and the elderly, should be sought wherever possible. Government authorities should be encouraged to control organophosphate product licensing, manufacture, storage, import, methods of use and delivery, food contamination and disposal.
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Affiliation(s)
- N A Minton
- National Poisons Unit, Guy's Hospital, London, England
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