Amitraz intoxication in children in the rural Black Sea region: analysis of forty-three patients

Amitraz toxicosis in 3 dogs after being in a rice field

OBJECTIVE

To describe the clinical course and novel biochemical findings in 3 dogs with amitraz toxicosis.

CASE SERIES SUMMARY

Three Labrador Retrievers developed acute onset obtundation to stupor after being in a rice field. On admittance to the hospital, they all displayed bradycardia, hyperglycemia, hyperlactatemia, respiratory acidosis, and metabolic alkalosis. All clinical signs resolved in 18-48 hours with supportive care. One dog represented with similar clinical signs and biochemical abnormalities 3 days after discharge following spending time in a different rice field owned by the same owner. Toxicological analysis of serum from all 3 dogs and vomitus from 1 dog returned positive for amitraz and one of its metabolites.

NEW OR UNIQUE INFORMATION PROVIDED

This is the first case series of dogs with confirmed amitraz toxicosis following an environmental exposure. Novel biochemical findings of hyperlactatemia, respiratory acidosis, and metabolic alkalosis were documented in all 3 dogs. Clinicians should be concerned for amitraz toxicosis when presented with an animal with the constellation of signs including decreased mental status, bradycardia, and hyperglycemia, particularly if relevant acid-base abnormalities are also detected.

Amitraz Poisoning - Tale of an Unusual Pesticide Poisoning: A Case Report

Amitraz is a formamidine group of compounds used in many parts of the world as an agricultural pesticide and an ectoparasiticide. Amitraz intoxication secondary to the oral, dermal or inhalational routes, both accidental and suicidal, has been encountered in humans leading to severe life-threatening side effects. Only very few cases of amitraz toxicity have been reported to date. This emphasizes the importance to ascertain amitraz intoxication from more commonly encountered pesticides like organophosphorus poisoning to avoid erroneous management of the patient. We report a case of a twenty-seven-year-old man who presented to the emergency room following suicidal ingestion of amitraz with the clinical manifestations of vomiting, altered sensorium, bradycardia and hypotension and complete recovery following supportive management.

Pediatric Poisonings in a Rural Ugandan Emergency Department

OBJECTIVE

This study aims to describe pediatric poisonings presenting to a rural Ugandan emergency department (ED), identifying demographic factors and causative agents.

METHODS

This retrospective study was conducted in the ED of a rural hospital in the Rukungiri District of Uganda. A prospectively collected quality assurance database of ED visits was queried for poisonings in patients under the age of 5 who were admitted to the hospital. Cases were included if the chief complaint or final diagnosis included anything referable to poisoning, ingestion, or intoxication, or if a toxicologic antidote was administered. The database was coded by a blinded investigator, and descriptive statistics were performed.

RESULTS

From November 9, 2009, to July 11, 2014, 3428 patients under the age of 5 were admitted to the hospital. A total of 123 cases (3.6%) met the inclusion criteria. Seventy-two patients were male (58.5%). The average age was 2.3 (SD, 0.97) years with 45 children (36.6%) under the age of 2 years. There were 19 cases (15.4%) lost to 3-day follow-up. The top 3 documented exposures responsible for pediatric poisonings were cow tick or organophosphates (36 cases, 29.2%), general poison or drug overdose (26 cases, 21.1%), and paraffin or hydrocarbon (24 cases, 19.5%).Of the admitted patients, 1 died in the ED and 2 died at 72-hour follow-up, for an overall 72-hour mortality of 2.4%. Patients who died were exposed to iron, cow tick, and rat poison.

CONCLUSIONS

Pediatric poisoning affects patients in rural sub-Saharan Africa. The mortality rate at one rural Ugandan hospital was greater than 2%.

Amitraz: A Perpetual Silent Menace Among Children in Developing Countries-A Case Report

Amitraz is an acaricide and insecticide used to treat ticks, which infest domestic animals in developing countries. Because of its widespread use, it is one of the common poisons unintentionally consumed by infants and children when left unsupervised. A 3-year-old boy was brought with unintentional consumption of Amitraz. On examination, he was found to be progressively drowsy, with an irregular pulse, bradycardia, and hypotension. He was treated with atropine, intravenous fluids, and dopamine infusion; hemodynamic stability was achieved within 36 hours after ingestion. Amitraz is an unusual but deadly poison unintentionally consumed by children. It can be suspected in the setting of rural households in developing countries having pets. There is no antidote available, and treatment is mainly supportive.

Pharmacokinetics and brain distribution of amitraz and its metabolites in rats

Amitraz is an acaricide and insecticide widely used in agriculture and veterinary medicine. Although central nervous system (CNS) toxicity is one of major toxicities following oral ingestion of amitraz, the understanding of the cause of the toxicity is limited. This study evaluated the systemic and brain exposure of amitraz and its major metabolites, BTS27271, 2',4'-formoxylidide, and 2,4-dimethylaniline following administration of amitraz in male Sprague-Dawley rats. Significant metabolism of amitraz was observed following the intravenous and oral administration. Amitraz related metabolites were majority of the total exposure observed, especially following oral administration. BTS27271 had higher brain exposure than amitraz and its other metabolites, which was due to low plasma protein binding but high brain tissue binding of BTS27271. Since BTS27271 has similar or higher toxicity and α₂-adrenoreceptor agonist potency than amitraz, its exposure in brain tissues may be the major cause of CNS toxicity of amitraz in animals and humans.

Intoxicación por amitraz. Un reporte de caso

El amitraz es un compuesto insecticida utilizado a nivel mundial para el control de plagas, en especial en áreas rurales agrícolas y ganaderas. La intoxicación por amitraz es infrecuente en Colombia. Se presenta el caso de una paciente de 18 años de edad, quien ingresa al servicio de urgencias 3 horas después de la ingesta de Triatox® (amitraz) en cantidad desconocida. La mujer llega con depresión del estado de conciencia, dificultad respiratoria, hipotensión, bradicardia, miosis y acidosis metabólica compensada con alcalosis respiratoria, por lo que se le suministra tratamiento inicial con medidas de soporte vital en el servicio de urgencias, con posterior necesidad de traslado y soporte en la unidad de cuidados intensivos, siendo dada de alta de la misma unidad 24 horas después del ingreso. El caso pone en consideración la similitud clínica entre la intoxicación por amitraz y la debida a otros compuestos tóxicos más frecuentes como carbamatos, organofosforados y opioides, los cuales requieren un manejo distinto.

Amitraz, an underrecognized poison: A systematic review

Background & objectives:

Amitraz is a member of formamidine family of pesticides. Poisoning from amitraz is underrecognized even in areas where it is widely available. It is frequently misdiagnosed as organophosphate poisoning. This systematic review provides information on the epidemiology, toxicokinetics, mechanisms of toxicity, clinical features, diagnosis and management of amitraz poisoning.

Methods:

Medline and Embase databases were searched systematically (since inception to January 2014) for case reports, case series and original articles using the following search terms: ‘amitraz’, ‘poisoning’, ‘toxicity’, ‘intoxication’ and ‘overdose’. Articles published in a language other than English, abstracts and those not providing sufficient clinical information were excluded.

Results:

The original search yielded 239 articles, of which 52 articles described human cases. After following the inclusion and exclusion criteria, 32 studies describing 310 cases (151 females, 175 children) of human poisoning with amitraz were included in this systematic review. The most commonly reported clinical features of amitraz poisoning were altered sensorium, miosis, hyperglycaemia, bradycardia, vomiting, respiratory failure, hypotension and hypothermia. Amitraz poisoning carried a good prognosis with only six reported deaths (case fatality rate, 1.9%). Nearly 20 and 11.9 per cent of the patients required mechanical ventilation and inotropic support, respectively. The role of decontamination methods, namely, gastric lavage and activated charcoal was unclear.

Interpretation & conclusions:

Our review shows that amitraz is an important agent for accidental or suicidal poisoning in both adults and children. It has a good prognosis with supportive management.

Poisoning Through Pediatric Skin: Cases from the Literature

Poisoning through pediatric skin leading to acute systemic symptoms is a relatively uncommonly reported phenomenon. Systemic toxicity through the skin typically occurs by direct contact between therapeutic or non-therapeutic topical agents and the skin. Though uncommon, poisoning through pediatric skin can have significant consequences and must be recognized so the offending agent may be discontinued and appropriate treatment initiated. We performed a literature search for all article types between 1950 and April 2016 to provide a single source of detectable cases of acute toxicity in pediatric patients due to percutaneous exposure. This literature review discusses relevant pediatric skin physiology along with reports of poisoning events that resulted in systemic signs and symptoms and even death to provide a comprehensive report on causes of pediatric poisoning through the skin.

Amitraz poisoning: A case report of an unusual pesticide poisoning in Sri Lanka and literature review

Background

Amitraz is a pesticide used worldwide on animals and in agriculture. It contains triazapentadiene, which is a centrally acting alpha-2 adrenergic agonist. Amitraz poisoning is fairly uncommon in humans and occurs via oral, dermal or inhalational routes. Only a limited number of case reports of human intoxication have been published and most of them are of accidental ingestion by children.

Case presentation

A twenty-year-old Sri Lankan female presented following self-ingestion of 20 ml of amitraz resulting in 37.8 mg/ kg of amitraz poisoning. She lost consciousness after 20 min of ingestion, developed bradycardia and hypotension, which needed intravenous fluid resuscitation and dobutamine. Gastric lavage was performed. Her bradycardia persisted for 36 h and she was drowsy for 48 h. She did not develop respiratory depression, convulsions or hypothermia and the urine output was normal. Arterial blood gas revealed mild respiratory alkalosis. She recovered fully within 48 h and was discharged on day 3.

Conclusion

The clinical manifestations of amitraz (impaired consciousness, drowsiness, vomiting, disorientation, miosis, mydriasis, hypotension, bradycardia, respiratory depression, hypothermia, generalized seizures, hyperglycemia and glycosuria) can be explained by the agonist action of amitraz on α1 and α2 receptors. Management of amitraz poisoning is still considered to be supportive and symptomatic with monitoring of nervous system, cardiovascular and respiratory systems. Activated charcoal may still be considered for treatment and the place for gastric lavage is controversial. Atropine is effective for symptomatic bradycardia and inotropic support is needed for hypotension that does not respond to fluid resuscitation. Diazepam or Lorazepam is used for convulsions and some patients may require intubation and ICU care. Several α2 adrenergic antagonists like yohimbine have been tried on animals, which have successfully reversed the effects of amitraz. Since the majority of amitraz poisoning cases are due to accidental ingestion, manufactures, regulatory authorities and national poisons control centers have a significant role to play in minimizing its occurrence.

Topical absorption and systemic toxicity

Dermal absorption of some chemicals and drugs can cause systemic toxicity. We evaluated several case reports from the past decade, which discuss the dermal absorption of a specific chemical and potential local and systemic effects. We focused on herbicide and pesticide exposure along with exposure to cutaneous medication, occupational contact, and cosmeceutical exposure. Although causality cannot be established in most cases, it is critical to be aware of the possible effects of topical absorption that may not be immediately apparent. We recommended further studies on specific chemicals to ascertain causality and determine the highest exposure level with no observed adverse affect level (NOAEL) and the reference dose (RfD). Post-marketing epidemiology data in most geographical areas are markedly limited. A weak link in public health resides in the inadequate reporting and workup of alleged chemically related adverse effects. This arena mandates a re-thinking of how to increase this reporting, and workup, as a backup to our preclinical and clinical studies. Public awareness and funding will be rewarded by increased evidence to backup pre-approval pre-marketing studies.

Amitraz poisoning in South Africa: a two year survey (2008-2009)

INTRODUCTION

Analysis of the annual pesticide poisoning statistics of the Tygerberg Poison Information Centre (TPIC) for the period 2005-2007 showed an increase in the number of amitraz poisonings. This prompted a 2-year survey (2008-2009) to establish the extent of amitraz poisoning in South Africa. Amitraz is a pesticide used as a tick dip. It acts as an α(2)-adrenoceptor agonist and the principal clinical effects of amitraz poisoning are related to its stimulation of these receptors;

METHODS

Data from amitraz poisoning cases in humans were evaluated for 2 years and analyzed for: demographic data, type of exposure, type of formulation, and clinical details. Serious cases were followed up;

RESULTS

4.6% of the pesticide poisoning cases were amitraz-related which comprised 0.8% of all TPIC poisoning consultations. Ingestion of amitraz formulations accounted for the majority of the cases (94%). Forty-one percent of cases were children (n = 28) and all were accidental exposures. Of the adult cases (59%), 88% were intentional ingestions. The majority of the cases were from the predominantly rural province of KwaZulu Natal (44.9%). CNS depression was the most common clinical sign (76.8%) followed by bradycardia 34.8%, respiratory depression 27.5%, miosis 27.5%, and hypotension 23.1%. Mechanical ventilation was required in 15.9% of cases. Other commonly reported clinical signs were hypothermia 15.9%, mydriasis 10.1%, and hyperglycaemia 7.2%. Supportive and symptomatic care was shown to be adequate treatment. Amitraz poisoning was misdiagnosed as cholinesterase inhibitor poisoning in 17.4% of cases;

CONCLUSION

This is the first report of amitraz poisoning in humans in Africa. The data suggest a different demographic pattern in South Africa to that currently reported in the literature. The study identified a very high incidence of intentional poisoning in adults. The misuse of amitraz for deliberate self-harm emphasizes the necessity for continued toxicovigilance.

Amitraz poisoning treatment: still supportive?

Amitraz is a triazapentadiene, an α₂ adrenergic agonist and a member of the amidine chemical family. A limited number of human intoxication cases have been published in the literature. Lack of a clear and specific protocol for the therapy of amitraz intoxication may make its successfully managed case reports useful and valuable for other clinical practitioners in poisoning departments.

The case is about a 22 years old female, single, university student, ingested a glass of amitraz poison (about 100 mL of a 20% solution) as a suicidal attempt on 11:30 am which was about 3.5 h before her hospital admission. She found nausea, vomiting, and dizziness. Immediately, her family took her to a clinic near their house. At that clinic (13:30 pm) she had miosis and they did gastric lavage , one adult dose of activated charcoal (50 g) and referred her to our Poisoning Emergency Department, where she was managed supportively and successfully.

Amitraz is a poisonous chemical which may cause central nervous system depression and also respiratory/cardiovascular symptoms as well. Several studies reported that using atropine for those amitraz poisoned patients with both miosis and bradycardia resolved the problem and recommend it as the first line of drug therapy when bradycardia occurs from vagal stimulation and atrioventricular block.

Management of amitraz poisoning is still considered to be supportive and symptomatic. Although the effects of activated charcoal and cathartics have not been studied, they may still be considered for treatment.

An uncommon but lethal poisoning - Amitraz

Amitraz, a centrally acting alpha-2 adrenergic agonist, is increasingly being used for treatment of ectoparasitic infestation in cattle. Its effects in humans may mimic organophosphate poisoning. We report a case of poisoning after suicidal ingestion of Amitraz. The patient presented in a deeply comatose state with respiratory depression, bradycardia and mydriasis (instead of miosis, the more common presentation in previous reports). He recovered completely within 24 hours with adequate supportive measures. The importance of this case report is highlighted by the increasing use of this compound, the life-threatening presentation, the excellent prognosis with early recognition and supportive management and the limited human toxicological data.

Acute Amitraz Poisoning in Adults: Clinical Features, Laboratory Findings, and Management

BACKGROUND

Amitraz is a formamidine pesticide widely used in agriculture and veterinary medicine as an insecticide and acaricide. Reports on amitraz poisoning in humans are not as prevalent as those in animals. Of human intoxications in the medical literature, the majority of intoxications are in children. The number of adult intoxications with amitraz is limited.

METHODS

In this study, we discuss the clinical features, laboratory findings, and management of 23 adults with amitraz poisoning cared for in our center. Data were extracted from the charts retrospectively, and included age, gender, mode of poisoning, initial symptoms, time to appearance of initial symptoms, clinical and laboratory findings, management, and prognosis.

RESULTS

Fourteen of 23 patients were female (61%). Ages ranged from 16 and 78 years (mean 38.6 +/- 19.8 years). Twenty-one patients ingested amitraz orally while one was exposed through skin contact and one probably through skin contact and/or inhalation. Seven patients ingested amitraz with intent to commit suicide and 11 patients accidentally. Vomiting, altered consciousness, and drowsiness were the predominant initial symptoms. Initially, hypotension was present in seven patients (30%), bradycardia in two (8.7%), myosis in six (26%), and mydriasis (without atropine administration) in three (13%). Time to appearance of the initial symptoms ranged from 5 to 120 minutes. Laboratory findings included an initial blood glucose level higher than 120 mg/dL in 62% of patients (mean 191 +/- 70 mg/dL) and elevations in AST levels in four patients (81 +/- 28 U/L) and ALT levels in three (60 +/- 14 U/L). Ten patients had central nervous system depression, which resolved spontaneously. Five patients required mechanical ventilation for respiratory depression (mean duration of mechanical ventilatory support: 50 +/- 16 hours). Six patients were thought to have been poisoned with an organophosphate and three with a carbamate pesticide due to confusing clinical picture; four of these nine patients received pralidoxim.

CONCLUSIONS

In spite of a rapidly progressing and life-threatening clinical picture, amitraz intoxication in humans carries a low morbidity and mortality when appropriate supportive treatment is given. No antidote has been developed for use in more serious cases. To prevent accidental ingestions, prominent and clear warning labels should be placed on its containers.

Neurotoxicity of pesticides

Several pesticides such as organophosphates, carbamates and the organochlorine pesticides directly target nervous tissue as their mechanism of toxicity. In several others, such as the fumigants, the nervous system is affected by toxicological mechanisms that diffusely affect most or all tissues in the body. Both the central and peripheral nervous system are involved in the acute toxidromes of many pesticides resulting in acute short-term effects. There is strong human epidemiological evidence for persistent nervous system damage following acute intoxication with several important pesticide groups such as organophosphates and certain fumigants. However, whether persistent nervous system damage follows chronic low-level exposure to pesticides in adults (particularly organophosphpates), and whether in utero and/or early childhood exposure leads to persistent nervous system damage, is a subject of study at present. Parkinson's Disease, one of the most common chronic central nervous system diseases, has been linked to pesticide exposure in some studies, but other studies have failed to find an association. Several new pesticidal chemicals such as the neo-nicotinoids and fipronil have central nervous system effects, but only case reports are available to date on acute human intoxications with several of these. Little data are yet available on whether long-term effects result from these chemicals. Several ongoing or recently completed studies should add valuable insight into the effects of pesticides on the human nervous system particularly the effect of low-dose, chronic exposure both in adults and children.

Amitraz: an unusual aetiology of Ogilvie's syndrome

Amitraz is an insecticide/acaricide of formamidine pesticides used worldwide for ectoparasites in animals. Because of its widespread use, amitraz poisoning is frequently encountered in Turkey.

CASE REPORT

A 36-year-old, comatose female was admitted to the hospital. Although it was stated that she had taken a glass of water containing amitraz, the exact volume of the substance was unknown. On admission, her Glasgow Coma Scale score was 10/15. Clinical findings were vomiting, miosis, bradycardia and hypotension. The patient's vital signs were body temperature 37.2 degrees C, pulse 54 bpm, blood pressure 80/50 mmHg and pulseoximetry 84%. Supportive treatment consisting of oxygen, fluid replacement and gastric lavage, activated charcoal and atropine was administered. On the second day, signs of Ogilvie's syndrome characterized by severe tenderness, distension and pain in the abdomen were seen. On the third day, the patient's condition improved except for abdominal distension and pain, inability to pass faeces or flatus through the anus. Although continuous nasogastric tube decompression was performed, her complaints were not resolved completely. Neostigmine was administered on the fourth day. On the fifth day, abdominal pain and distension were decreased, and stool passage began. She had a complete clinical and laboratory improvement, which warranted her discharge on the seventh day of admission.

Modification of MTT assay conditions to examine the cytotoxic effects of amitraz on the human lymphoblastoid cell line, WIL2NS

Reported parameters of the MTT assay vary widely, and reflect a need to optimise the assay for different cell types. The MTT assay conditions for the human B-lymphocyte-derived cell line WIL2NS were optimised for MTT incubation and formazan development. The optimised MTT assay was validated by examining the effects of the acaride amitraz on WIL2NS. In pH-buffered media in the absence of cells, MTT formed formazan spontaneously, and absorbance was proportional to both the initial concentration of MTT and the time of incubation at 37 degrees C. One milligram per millilitre MTT was toxic to WIL2NS cells, but the accuracy of the standard curve was reduced when only 0.2 mg/ml MTT was used. Twenty percent SDS in 0.2 M HCl was preferable to DMSO as a solvent for formazan. Exposure to 0.035% amitraz resulted in a significant reduction in WIL2NS cell numbers after only 2 h of exposure. It was concluded that 0.035% of amitraz has the potential to adversely affect lymphocytes in the systemic blood system in humans, and that an optimised MTT assay was obtained by incubating WIL2NS cells with 0.45 mg/ml MTT for 17 h, followed by addition of acidified SDS for 1 h.

Effects of the insecticide amitraz, an α2-adrenergic receptor agonist, on human luteinized granulosa cells

BACKGROUND

Amitraz, an insecticide used to prevent tick and mite infestation of cattle, crops and dogs, is an alpha2-adrenergic receptor agonist that inhibits GnRH release and the ovulatory LH surge in rats. Noradrenalin, the physiological ligand for adrenergic receptors, inhibits progesterone production by IVF-derived granulosa cells, but the effects of amitraz are unknown.

METHODS

Luteinized granulosa cells obtained from women undergoing ovarian stimulation were exposed to amitraz (1, 10, 50, 100 microg/ml) for 2-72 h, and to amitraz (50 microg/ml) +/- hCG or the specific alpha2-adrenergic receptor antagonist yohimbine, for 6 h. Cell numbers were determined by 3-(4, 5-dimethylthiazol-(2)-yl)-2, 5-diphenyl tetrazolium bromide(MTT) assay and hormone production by radioimmunoassay.

RESULTS

Amitraz 10 microg/ml did not affect cell numbers or estrogen production, but reduced progesterone production to 58 +/- 8% (p < 0.01, 24 h, n = 6) of control values. Amitraz (100 microg/ml) was cytotoxic and caused a corresponding reduction in hormone production. Amitraz 50 microg/ml did not affect cell numbers or estrogen production, but reduced progesterone per cell production to 82 +/- 6% of control values after 6 h. This was prevented by 0.2 mmol/l yohimbine. Exposure to amitraz 50 microg/ml for 6 h exposure abolished hCG-stimulated progesterone production but not estrogen production.

CONCLUSIONS

Amitraz inhibited basal and hCG-stimulated progesterone but not estrogen production. The inhibitory action of amitraz and its antagonism by yohimbine suggest that alpha2-adrenergic receptors are expressed by luteinized human granulosa cells.

Amitraz poisoning, an emerging problem: epidemiology, clinical features, management, and preventive strategies

BACKGROUND

Amitraz is a pharmaceutical, veterinary, and agricultural product which is used worldwide under numerous generic names as an acaricide and insecticide. Because of its widespread use amitraz poisoning has come emerged as a cause of childhood poisoning during the past decade, particularly more in certain countries such as Turkey.

AIMS AND METHODS

To report the clinical features, the management, and the preventive strategies of amitraz poisoning in nine children, and review the previously reported 137 cases in humans.

RESULTS

Five male and four female children aged 10 months to 8 years were admitted to our department. The estimated ingested dose ranged between 89.2 and 163 mg/kg and estimated time from ingestion to presentation was 30-120 minutes. The initial signs and symptoms were impaired consciousness, drowsiness, vomiting, disorientation, miosis, mydriasis, hypotension, bradycardia, tachypnoea, hypothermia, and generalised seizures. Hyperglycaemia, glycosuria, and minimal increase in transaminase levels were observed. None required mechanical ventilation. CNS depression resolved spontaneously within 4-28 hours in all. The length of hospital stay was two to three days; all had a good outcome.

CONCLUSION

This review details preventive measures and management strategies of amitraz poisoning, including the importance of following patients closely in the intensive care unit, monitoring their respiratory, cardiovascular, and central nervous systems since they may occasionally experience serious cardiopulmonary side effects.

Poisoning with Amitraz

Amitraz, an insecticide and veterinary medicine, has been available in many countries since 1974 but reports of poisoning with it have only become prominent in the last 7 years. The vast majority of cases have occurred in Turkey and have involved children. The data available, both human and animal, do not allow clear separation of the features of toxicity of amitraz from those of the hydrocarbon solvents in which it is commonly dissolved. Amitraz stimulates alpha 2-adrenoceptors resulting in impairment of consciousness, respiratory depression, convulsions, bradycardia, hypotension, hypothermia and hypoglycaemia. Even the most severely poisoned patients recover with nothing more than intensive care; only one possible death has been documented. Animal studies indicate that the alpha 2-adrenoceptor antagonists, yohimbine and atipamezole, can reverse amitraz-induced toxicity but they have not been assessed in poisoned humans.