Arsenic Trioxide 

Arsenic Trioxide (As O ) 2 3 

CAS 1327-53-3; UN 1561 

Synonyms include arsenic oxide, arsenious acid, arsenious oxide, arsenious trioxide, arsenous acid 

anhydride, crude arsenic, arsenolite, and white arsenic. 

• Persons whose clothing or skin is contaminated with arsenic trioxide can 

secondarily contaminate rescuers by direct contact or through release of inhalable 

dust. 

• Arsenic trioxide is an odorless, tasteless, white or transparent nonflammable solid. 

• Arsenic trioxide is readily absorbed if inhaled or ingested, but only slowly absorbed 

through the skin. Toxicity usually results from ingestion. 

Description There are many forms of arsenic, but this medical Management 

Guideline focuses specifically on arsenic trioxide (As O ), one of 2 3 

the most toxic and prevalent forms. Arsenic trioxide is a white 

or transparent solid in the form of glassy, shapeless lumps or a 

crystalline powder that resembles sugar. It has no odor or taste. 

It forms readily when elemental metallic arsenic is heated to high 

temperatures or burned. When arsenic trioxide is burned, it 

releases toxic fumes and arsine gas which is highly toxic. 

Routes of Exposure 

Inhalation Arsenic trioxide dust is readily absorbed from the lungs, but 

inhaled quantities are usually insufficient to cause acute systemic 

toxicity. Arsenic trioxide has no odor. Thus, odor provides no 

warning of hazardous airborne concentrations. 

Skin/Eye Contact Direct contact with arsenic trioxide dust can cause localized skin 

irritation, but systemic absorption through the skin is negligible. 

Skin contact is unlikely to cause systemic effects unless the 

dermal barrier is compromised. Arsenic trioxide dust is irritating 

to the eyes. 

Ingestion Ingestion is the most important route of acute exposure of 

arsenic trioxide. Ingested arsenic trioxide is quickly absorbed and 

can be extremely hazardous. Significant tissue and organ damage 

and death may result. Most acute intoxications are from suicidal 

or homicidal ingestion. 

ATSDR • General Information 1 
 

Arsenic Trioxide 

Sources/Uses 

Standards and 

Guidelines 

Physical Properties 

Arsenic is ubiquitous in the natural environment. Arsenic trioxide 

is one of the arsenites (inorganic forms of arsenic in the trivalent 

state [As

3+]), found in nature and is produced mainly from byproducts of copper smelting. It is no longer commercially 

manufactured in the United States, but is imported primarily for 

use in manufacturing other arsenic compounds used as wood 

preservatives, insecticides, and herbicides. It is also used in 

metallurgical processes, and in the manufacturing of glass and 

ceramics. Arsenic compounds were formerly used medicinally in 

humans (e.g., Fowler’s solution), but these uses have largely 

been abandoned. Inorganic arsenic compounds, however, can be 

found in some homeopathic and folk remedies. 

3 OSHA PEL (permissible exposure limit) = 10 μg/m (averaged

over an 8-hour workshift) for inorganic arsenic compounds. 

NIOSH IDLH (immediately dangerous to life or health) = 5 mg 

3 As/m (for all inorganic arsenic compounds).

Description: white or transparent solid in the form of glassy, 

shapeless lumps or a crystalline powder that resembles sugar. 

Warning properties: inadequate; odorless and tasteless; airborne 

arsenic trioxide may produce a burning sensation to the nose, 

mouth, and eyes and cause coughing, shortness of breath, 

headache, sore throat, and dizziness. 

Molecular weight: 197.84 daltons
 

Boiling point (760 mm Hg): 869 EF (465EC)
 

Sublimes at 379 EF (193EC)
 

Melting point: 594 EF (312EC)
 

Vapor pressure: 66.1 mm Hg at 594 EF (312 EC)
 

Density (solid): 3.74 (water = 1.00)
 

Water solubility: Low solubility in water (37 g/L at 20 EC,
 

115 g/L at 100 EC); slightly soluble in alcohol; soluble in dilute 

HCl solutions. 

Flammability: not flammable, but emits highly toxic arsine gas 

and oxides of arsenic fumes when burned. 

2 General Information • ATSDR 
 

Arsenic Trioxide 

Incompatibilities	 Flammable reactions can occur in the presence of strong 

oxidizers. If arsenic trioxide is exposed to hydrogen gas or to the 

combination of acid (acid fumes) or water and active metals, the 

reaction can form toxic arsine gas (see Medical Management 

Guideline for Arsine). 

ATSDR • General Information 3 
 

Arsenic Trioxide 

4 General Information • ATSDR 
 

Arsenic Trioxide 

Health Effects 

• Toxic effects of arsenic trioxide usually result from ingestion. Small amounts of 

arsenic trioxide can lead to multiple organ damage and death. Acute signs and 

symptoms include nausea, vomiting, diarrhea, gastrointestinal hemorrhage, cerebral 

edema, tachycardia, dysrhythmias, and hypovolemic shock. Symptoms are dose 

dependent and can be delayed. 

• Dermal contact and inhalation of airborne arsenic trioxide can cause localized 

irritation and usually does not result in systemic effects. 

Acute Exposure	 The toxic effects caused by acute exposure to arsenic trioxide 

are due in large part to its ability to bind to cellular proteins 

containing sulfhydryl groups. This inhibits the production of 

energy needed to maintain tissue functions, and results in a 

decrease in glutathione, which is necessary for the metabolic 

detoxification of arsenic. The primary target organs are the 

gastrointestinal tract, heart, brain and kidney. Eventually the 

skin, bone marrow and peripheral nervous system are also 

affected. Arsenic trioxide has direct toxic effects on endothelial 

cells, increasing the permeability of small blood vessels. 

Children do not always respond to chemicals in the same way 

that adults do. Different protocols for managing their care may 

be needed. 

This medical management guide focuses specifically on arsenic 

trioxide (an arsenite), which is one of the most toxic forms of 

arsenic. As little as 1 to 2.5 mg/kg of arsenic trioxide is a 

potentially fatal dose. Toxicity from natural sources of arsenic is 

rare except from drinking highly contaminated groundwater or 

from breathing highly contaminated air (e.g., from burning of 

arsenic-containing coal indoors without adequate ventilation). 

Other inorganic forms of arsenic called arsenates are in the 

5+ pentavalent state (As ) and are several times less toxic than the

arsenites. Elemental arsenic has a gray metal-like appearance, is 

insoluble in water or body fluids, and is not considered 

poisonous. Organic arsenic, also known as fish or seaweed 

arsenic (arsenocholine, arsenobetaine, or arsenosugars) is mostly 

found in seafood such as bivalves, bottom-feeding fish, and 

seaweed and has a lower toxicity. 

Gastrointestinal	 Initial symptoms occurring within 30 minutes to several hours 

include burning of the lips, pharyngeal constriction, severe 

abdominal pain and nausea. A metallic or garlic taste and intense 

ATSDR • Health Effects 5 
 

Arsenic Trioxide 

CNS 

Peripheral Neurologic 

Cardiovascular 

Respiratory 

Musculoskeletal 

Renal 

thirst also occur. Inflammation and necrosis of the mucosa and 

submucosa can lead to bloody or “rice water” diarrhea, 

vomiting, and gastrointestinal perforation and bleeding. Bleeding 

and/or fluid loss can result in electrolyte abnormalities, shock, 

and death. 

Encephalopathy (cerebral edema), headache, lethargy, delirium, 

hallucinations, seizures, or coma can occur. Cerebral lesions 

consisting of multiple, symmetrical foci of hemorrhagic necrosis 

occur in the gray and white matter. 

Peripheral neuropathy resembling Guillain-Barré syndrome 

(ascending flaccid paralysis) is common acutely or subacutely. 

Sensory symptoms predominate early, with patients complaining 

of “pins and needles” or electrical shock like pains in the lower 

extremities. This may be followed by numbness and motor 

weakness. 

Increased capillary permeability (third-spacing and vasodilation) 

can result in hypovolemic shock. Sinus tachycardia can be an 

early sign of poisoning. Polymorphous ventricular tachycardia, 

ventricular fibrillation, and congestive heart failure can occur. 

Electrocardiographic findings can include, prolongation of the 

QT interval, ST depression, and flattened T waves. 

Pulmonary edema, acute respiratory distress syndrome (ARDS), 

and respiratory failure due to weakness of the respiratory 

muscles can occur following ingestion. Coughing, chest pain, 

dyspnea, and general irritation of the upper respiratory tract can 

occur following inhalation. 

Exposure to certain chemicals can lead to Reactive Airway 

Dysfunction Syndrome (RADS), a chemically- or irritantinduced type of asthma. 

Children may be more vulnerable because of relatively increased 

minute ventilation per kg and failure to evacuate an area 

promptly when exposed. 

Myalgia, weakness, muscular atrophy and rhabdomyolysis can 

occur. 

Initial glomerular damage leading to proteinuria is common 

following high arsenic exposure. Tubular necrosis and 

degeneration, oliguria with proteinuria, hematuria and acute 

renal failure are also frequently observed. 

6 Health Effects • ATSDR 
 

Arsenic Trioxide 

Hepatic 

Dermal 

Ocular 

Potential Sequelae 

Chronic Exposure 

Carcinogenicity 

Hepatocellular injury after acute exposure to inorganic arsenicals 

is uncommon, but fatty infiltration of the liver, central necrosis, 

and cirrhosis may occur. Hepatitis may also develop due to 

altered intrahepatic heme metabolism, increased synthesis of 

bilirubin, and altered interhepatocyte protein transport. 

Flushing, diaphoresis, edema (especially periorbital), 

hyperkeratosis, and brawny desquamation or exfoliative 

dermatitis can occur. 

Conjunctivitis, photophobia, and dimness of vision, diplopia, and 

lacrimation can occur. 

If the immediate effects of acute arsenic poisoning are survived, 

a variety of delayed effects, including peripheral neuropathy and 

bone marrow suppression (anemia, leukopenia, pancytopenia), 

may develop. New or persistent encephalopathy, dysrhythmias, 

and nail changes (Mee’s lines) can also occur. Peripheral 

neuropathy involves sensory and motor neurons in a stockingglove distribution. Initially painful dysesthesias (i.e., “pins and 

needles” or an electric shock-like sensation) are prominent. Early 

treatment with the chelator dimercaprol, also known as BAL 

(British AntiLewisite), may not eliminate the risk of delayed 

effects. Survival of the acute phase of arsenic poisoning is highly 

dependent on the dose received and the timing and extent of 

treatment. Recovery from subsequent peripheral neuropathy is 

usually only partial and may require months to years. 

Chronic exposure is characterized by malaise, peripheral 

sensorimotor neuropathy, anemia, jaundice, gastrointestinal 

complaints, and characteristic skin lesions including 

hyperkeratosis (small corn-like elevations) and 

hyperpigmentation. Hyperkeratosis usually appears on the palms 

or soles. Pigmentation changes and hyperkeratosis can take 3 to 

7 years to appear. Chronic inhalation can also lead to 

conjunctivitis, irritation of the throat and respiratory tract, and 

perforation of the nasal septum. Chronic exposure can cause 

allergic contact dermatitis. Chronic exposure may be more 

serious for children because of their potential longer latency 

period. 

The Department of Health and Human Services (DHHS), the 

International Agency for Research on Cancer (IARC), the 

Environmental Protection Agency (EPA), and the National 

Toxicology Program (NTP) have classified arsenic as a human 

carcinogen based on sufficient evidence from human data. 

Arsenic trioxide causes skin and lung cancer, and may cause 

ATSDR • Health Effects 7 
 

Arsenic Trioxide 

internal cancers such as liver, bladder, kidney, colon, and 

prostate cancers. 

Reproductive and 

Developmental Effects	 Arsenic ions released from arsenic trioxide within the body can 

cross the placenta and affect the developing fetus; arsenic is also 

excreted in breast milk. Experimental animal studies support an 

association between high ingested arsenic dose and fetal toxicity. 

Arsenic trioxide is not included in Reproductive and 

Developmental Toxicants, a 1991 report published by the 

General Accounting Office (GAO) that lists 30 chemicals of 

concern because of widely acknowledged reproductive and 

developmental consequences. 

Special consideration regarding the exposure of pregnant women 

may be warranted, since arsenic trioxide has been shown to be 

mutagenic and clastogenic, and is suspected of being teratogenic; 

thus, medical counseling is recommended for the acutely 

exposed pregnant woman. 

8 Health Effects • ATSDR 
 

Arsenic Trioxide 

Prehospital Management 

• Exposed persons whose skin or clothing is contaminated with arsenic trioxide can 

contaminate rescuers by direct contact or through release of inhalable dust. 

• There is no serious risk of secondary contamination after clothing is removed and the 

skin is washed. 

• Arsenic trioxide is irritating to the skin, eyes, and respiratory tract. Systemic effects 

can occur from all routes of exposure and may include severe gastrointestinal injury, 

life-threatening shock, and nerve damage. 

• There is no specific antidote for arsenic trioxide. Prehospital treatment consists of 

supportive care and gastric decontamination. Chelation therapy is strongly 

recommended. 

Hot Zone	 Rescuers should be trained and appropriately attired before 

entering the Hot Zone. If the proper equipment is not available, 

or if the rescuers have not been trained in its use, call for 

assistance from a local or regional HAZMAT team or other 

properly equipped response organization. 

Rescuer Protection	 Arsenic trioxide dust is readily absorbed through inhalation and 

can irritate the respiratory tract. Although it is poorly absorbed 

dermally, skin contact should be avoided because arsenic trioxide 

can irritate the skin. 

Respiratory Protection: Positive-pressure, self-contained 

breathing apparatus (SCBA) is recommended in response 

situations that involve exposure to potentially unsafe levels of 

arsenic trioxide or combustion products (arsine and arsenic 

trioxide fumes). 

Skin Protection: Chemical-protective clothing is recommended 

when contact with arsenic trioxide is expected because skin 

irritation might occur. 

ABC Reminders	 Quickly access for a patent airway, ensure adequate respiration 

and pulse. If trauma is suspected, manually maintain cervical 

immobilization and apply a cervical collar and a backboard when 

feasible. Apply direct pressure to stop any heavy bleeding. 

Maintain adequate circulation. 

Victim Removal	 If victims can walk, lead them out of the Hot Zone to the 

Decontamination Zone. Victims who are unable to walk should 

ATSDR • Prehospital Management 9 
 

Arsenic Trioxide 

Decontamination Zone 

Rescuer Protection 

ABC Reminders 

Basic Decontamination 

be removed on backboards or gurneys. If these are not available, 

carefully carry or drag victims to safety. 

Consider appropriate management of chemically contaminated 

children, anticipate separation anxiety if a child is separated from 

a parent or other adult. 

All victims exposed to arsenic trioxide require decontamination 

(see Basic Decontamination, below). 

If exposure levels are determined to be safe, decontamination 

may be conducted by personnel wearing a lower level of 

protection than that required in the Hot Zone (described above). 

Quickly access for a patent airway, ensure adequate respiration 

and pulse. Maintain adequate circulation. If trauma is suspected, 

manually maintain cervical immobilization and apply a cervical 

collar and a backboard when feasible. Administer supplemental 

oxygen as required. Assist ventilation with a bag-valve-mask 

device if necessary. Apply direct pressure to control any 

bleeding. 

Victims who are able may assist with their own decontamination. 

Remove and double-bag contaminated clothing and all personal 

belongings. 

Wash exposed skin and hair with mild soap and water 

(preferably under a shower). Rinse thoroughly with water. Use 

caution to avoid hypothermia when decontaminating children or 

the elderly. Use blankets or warmers when appropriate. 

Flush exposed or irritated eyes with plain water or saline for at 

least 15 minutes. Remove contact lenses if easily removable 

without additional trauma to the eye. If pain or injury is evident, 

continue irrigation while transferring the victim to the Support 

Zone. 

In cases of ingestion, do not induce emesis. Aggressive 

decontamination with gastric lavage is recommended within 

1 hour of ingestion of a life-threatening amount of poison. The 

effectiveness of activated charcoal in binding arsenic trioxide is 

questionable, but administration of a charcoal slurry is 

recommended pending further evaluation in cases of ingestion of 

unknown quantities (at 1 gm/kg, usual adult dose 60–90 g, child 

dose 25–50 g). A soda can and straw may be of assistance when 

offering charcoal to a child. 

10 Prehospital Management • ATSDR 
 

Arsenic Trioxide 

Transfer to Support Zone 

Support Zone 

ABC Reminders 

Additional Decontamination 

Advanced Treatment 

Consider appropriate management of chemically contaminated 

children at the exposure site. Also, provide reassurance to the 

child during decontamination, especially if separation from a 

parent occurs. If possible, seek assistance from a child separation 

expert. 

As soon as basic decontamination is complete, move the victim 

to the Support Zone. 

Be certain that victims have been decontaminated properly (see 

Decontamination Zone, above). Victims who have undergone 

decontamination pose no serious risk of secondary 

contamination to rescuers. In such cases, Support Zone 

personnel require no specialized protective gear. 

Quickly access for a patent airway, ensure adequate respiration 

and pulse. If trauma is suspected, manually maintain cervical 

immobilization and apply a cervical collar and a backboard when 

feasible. Administer supplemental oxygen as required. Assist 

ventilation with a bag-valve-mask device, if necessary. Maintain 

adequate circulation. Apply direct pressure to control any 

bleeding. Establish intravenous access, if necessary. Place on a 

cardiac monitor. 

If evidence of shock or hypotension is observed begin fluid 

administration. For adults, bolus 1,000 mL/hour if blood 

pressure is under 80 mm Hg; if systolic pressure is over 90 mm 

Hg, an infusion rate of 150 to 200 mL/hour is sufficient. For 

children with compromised perfusion administer a 20 mL/kg 

bolus of normal saline over 10 to 20 minutes, then infuse at 2 to 

3 mL/kg/hour. 

Continue irrigating exposed skin and eyes, as appropriate. In 

cases of ingestion, do not induce emesis. Aggressive 

decontamination with gastric lavage is recommended within 

1 hour of ingestion of a life-threatening amount of poison. The 

effectiveness of activated charcoal in binding arsenic trioxide is 

questionable, but administration of a charcoal slurry is 

recommended pending further evaluation in cases of ingestion of 

unknown quantities (at 1 gm/kg, usual adult dose 60–90 g, child 

dose 25–50 g). A soda can and straw may be of assistance when 

offering charcoal to a child. 

In cases of respiratory compromise secure airway and respiration 

via endotracheal intubation. If not possible, perform 

cricothyroidotomy if equipped and trained to do so. 

ATSDR • Prehospital Management 11 
 

Arsenic Trioxide 

Transport to Medical Facility 

Multi-Casualty Triage 

Treat patients who have bronchospasm with aerosolized 

bronchodilators. The use of bronchial sensitizing agents in 

situations of multiple chemical exposures may pose additional 

risks. Also consider the health of the myocardium before 

choosing which type of bronchodilator should be administered. 

Cardiac sensitizing agents may be appropriate; however, the use 

of cardiac sensitizing agents after exposure to certain chemicals 

may pose enhanced risk of cardiac arrhythmias (especially in the 

elderly). Arsenic trioxide poisoning is not known to pose 

additional risk during the use of bronchial or cardiac sensitizing 

agents. 

Consider racemic epinephrine aerosol for children who develop 

stridor. Dose 0.25–0.75 mL of 2.25% racemic epinephrine 

solution in 2.5 cc water, repeat every 20 minutes as needed 

cautioning for myocardial variability. 

Patients who are comatose, hypotensive, or have seizures or 

cardiac dysrhythmias should be treated according to advanced 

life support (ALS) protocols. 

If massive exposure is suspected or if the patient is hypotensive, 

infuse intravenous saline or lactated Ringer’s solution. For 

adults, bolus 1,000 mL/hour if blood pressure is under 80 mm 

Hg; if systolic pressure is over 90 mm Hg, an infusion rate of 

150 to 200 mL/hour is sufficient. For children with compromised 

perfusion administer a 20 mL/kg bolus of normal saline over 10 

to 20 minutes, then infuse at 2 to 3 mL/kg/hour. 

Only decontaminated patients or patients not requiring 

decontamination should be transported to a medical facility. 

“Body bags” are not recommended. 

Report to the base station and the receiving medical facility the 

condition of the patient, treatment given, and estimated time of 

arrival at the medical facility. 

If the patient has ingested arsenic trioxide, prepare the 

ambulance in case the patient vomits toxic material or has 

diarrhea. Have ready several towels and open plastic bags to 

quickly clean up and isolate vomitus. 

Consult with the base station physician or the regional poison 

control center for advice regarding triage of multiple victims. 

12 Prehospital Management • ATSDR 
 

Arsenic Trioxide 

Patients with evidence of significant exposure and all patients 

who have ingested arsenic trioxide should be transported to a 

medical facility for evaluation. 

Asymptomatic patients who have not had direct exposure to 

arsenic trioxide may be discharged from the scene, after their 

names, addresses, and telephone numbers are recorded. These 

patients should be advised to seek medical care promptly if 

symptoms develop (see Patient Information Sheet below). 

ATSDR • Prehospital Management 13 
 

Arsenic Trioxide 

14 Prehospital Management • ATSDR 
 

Arsenic Trioxide 

Emergency Department Management 

• Patients whose skin or clothing is contaminated with arsenic trioxide can 

contaminate rescuers by direct contact or through release of inhalable dust. 

• Patients do not pose a serious risk of secondary contamination after their clothing is 

removed and their skin is washed. 

• Arsenic trioxide is irritating to the skin, eyes, and respiratory tract. Systemic effects 

can occur from all routes of exposure and may include gastrointestinal injury, lifethreatening shock, and nerve damage. 

• There is no specific antidote for arsenic trioxide. Treatment consists of supportive 

care and gastric decontamination. Chelation therapy is strongly recommended.

Decontamination Area	 Previously decontaminated patients may be transferred directly 

to the Critical Care Area. Others require decontamination as 

described below. Because arsenic trioxide can irritate the skin, 

thus increasing the probability of dermal absorption, chemicalprotective clothing is recommended when contact with arsenic 

trioxide is expected. 

Be aware that use of protective equipment by the provider may 

cause fear in children, resulting in decreased compliance with 

further management efforts. 

Because of their relatively larger surface area:weight ratio, 

children are more vulnerable to toxicants absorbed through the 

skin. Also, emergency room personnel should examine children’s 

mouths because of the frequency of hand-to-mouth activity 

among children. 

ABC Reminders	 Evaluate and support the airway, breathing, and circulation. 

Secure airway and respiration via endotracheal intubation. If not 

possible, perform cricothyroidotomy if equipped and trained to 

do so. 

Treat patients who have bronchospasm with aerosolized 

bronchodilators. The use of bronchial sensitizing agents in 

situations of multiple chemical exposures may pose additional 

risks. Also consider the health of the myocardium before 

choosing which type of bronchodilator should be administered. 

Cardiac sensitizing agents may be appropriate; however, the use 

of cardiac sensitizing agents after exposure to certain chemicals 

may pose enhanced risk of cardiac arrhythmias (especially in the 

elderly). Arsenic trioxide poisoning is not known to pose 

ATSDR • Emergency Department Management 15 
 

Arsenic Trioxide 

Basic Decontamination 

Critical Care Area 

ABC Reminders 

Inhalation Exposure 

additional risk during the use of bronchial or cardiac sensitizing 

agents. 

Consider racemic epinephrine aerosol for children who develop 

stridor. Dose 0.25–0.75 mL of 2.25% racemic epinephrine 

solution in 2.5 cc water, repeat every 20 minutes as needed 

cautioning for myocardial variability. 

Patients who are comatose, hypotensive, or have seizures or 

cardiac dysrhythmias should be treated in the conventional 

manner. 

Patients who are able and cooperative may assist with their own 

decontamination. Remove and double-bag contaminated clothing 

and all personal belongings. 

Wash exposed skin and hair with mild soap and water 

(preferably under a shower). Rinse thoroughly with water. 

Flush exposed or irritated eyes with plain water or saline for at 

least 15 minutes. Remove contact lenses if present and easily 

removable without additional trauma to the eye. If ocular pain or 

injury is evident, continue irrigation while transferring the victim 

to the Critical Care Area. 

In cases of ingestion, do not induce emesis. Consider gastric 

lavage for recent large ingestion. (More information is provided 

in Ingestion Exposure under Critical Care Area below). 

Be certain that appropriate decontamination has been carried out 

(see Decontamination Area above). 

Evaluate and support the airway, breathing, and circulation as in 

ABC Reminders above. Children may be more vulnerable to 

corrosive agents than adults because of the relatively smaller 

diameter of their airways. Establish intravenous access in 

symptomatic patients. Continuously monitor cardiac rhythm. 

Patients who are comatose, hypotensive, or have seizures or 

cardiac dysrhythmias should be treated in the conventional 

manner. 

Administer supplemental oxygen by mask to patients who have 

respiratory complaints. For serious exposure, respiratory tract 

irritation can progress to pulmonary edema, maintain adequate 

oxygenation and provide mechanical support if needed. Treat 

patients who have bronchospasm with aerosolized 

16 Emergency Department Management • ATSDR 
 

Arsenic Trioxide 

Skin Exposure
 

Eye Exposure
 

Ingestion Exposure 

bronchodilators. The use of bronchial sensitizing agents in 

situations of multiple chemical exposures may pose additional 

risks. Also consider the health of the myocardium before 

choosing which type of bronchodilator should be administered. 

Dopamine or norepinephrine may be appropriate in management 

of shock; however, the use of cardiac sensitizing agents after 

exposure to certain chemicals may pose enhanced risk of cardiac 

arrhythmias (especially in the elderly). Arsenic trioxide poisoning 

is not known to pose additional risk during the use of bronchial 

or cardiac sensitizing agents. 

Consider racemic epinephrine aerosol for children who develop 

stridor. Dose 0.25–0.75 mL of 2.25% racemic epinephrine 

solution in 2.5 cc water, repeat every 20 minutes as needed 

cautioning for myocardial variability. 

Dermal exposure to arsenic trioxide may cause skin irritation. 

Treat symptomatically. 

Ensure that adequate eye irrigation has been completed. Test 

visual acuity. Examine the eyes for corneal damage and treat 

appropriately. Consult an ophthalmologist for patients who have 

apparent or suspected corneal injury. 

Fluid repletion should begin as soon as possible in severe acute 

poisoning. Central venous or pulmonary wedge pressure 

monitoring can be useful in managing severe exposures where 

hypotension is a risk. 

Do not induce emesis. In case of recent ingestion (less than 

1 hour), and if spontaneous emesis has not occurred, consider 

performing gastric lavage to prevent further absorption. Insert an 

orogastric tube and begin lavage with water or normal saline as 

soon as possible. Continue lavage until the return is clear. 

Activated charcoal may not bind significant amounts but is 

recommended (at 1 gm/kg, usual adult dose 60–90 g, child dose 

25–50 g). 

Arsenic is radiopaque and an abdominal radiograph should be 

obtained in cases of ingestion. If opacities compatible with 

arsenic are noted on the radiograph, consider whole bowel 

irrigation (e.g., with a polyethylene glycol [PEG-3350] 

electrolyte lavage solution). 

Consider alkalization of urine (pH 7.5) to protect kidney from 

deposition of red cell breakdown products. Assure adequate 

renal function before administering sodium bicarbonate. 

ATSDR • Emergency Department Management 17 
 

Arsenic Trioxide 

Antidotes and 

Other Treatments 

Chelation therapy curtails the distribution of arsenic in the body 

and reduces the body burden. The decision to chelate for a 

patient should be made only by professionals experienced in the 

use of chelation, preferably in consultation with a regional 

poison control center or a medical toxicologist. Patients with a 

clear history of exposure to arsenic with significant GI and/or 

cardiovascular symptoms may require chelation before 

laboratory confirmation. As time increases after exposure, 

chelation therapy becomes less effective in reducing the severity 

of poisoning and in reducing the risks of serious delayed effects. 

Do not chelate asymptomatic patients without the guidance of a 

24-hour urinary arsenic level. 

In acutely ill patients, the agent most frequently recommended 

is dimercaprol, also known as BAL (British AntiLewisite). The 

standard dosage regimen is 3 to 5 mg/kg IM every 4–6 hours 

until the 24-hour urinary arsenic level falls below 50 μg/L, unless 

an orally administered chelating agent (e.g., DMSA, see below) 

is substituted. This regimen may be adjusted depending upon the 

severity of the exposure and the symptoms. 

Contraindications to BAL include preexisting renal disease, 

pregnancy (except in life-threatening circumstances) and 

concurrent use of medicinal iron (BAL and iron together 

form a complex that is very toxic). 

An increased risk for hemolysis should also be considered when 

administering BAL to patients with glucose-6-phosphate 

dehydrogenase deficiency; arsenic trioxide is itself an inhibitor of 

G-6-PD. 

Chelation therapy should be continued until the 24-hour urinary 

arsenic level falls below 50 μg/L. Alkalization of the urine 

stabilizes the dimercaprol-metal complex and has been proposed 

to protect the kidneys during chelation therapy. If any degree of 

acute renal insufficiency develops during chelation, hemodialysis 

should be considered to remove the dimercaprol-arsenic 

complex. Side effects of BAL administered at 2.5 mg/kg are 

mostly pain at the injection site. At an intramuscular dose of 

5 mg/kg, the effects can include hypertension, nausea, vomiting, 

headache, lacrimation, rhinorrhea, salivation, and diaphoresis. 

Oral agents such as 2,3-demercaptosuccinic acid (DMSA or 

Succimer®) or D-penicillamine have been used as alternatives to 

BAL. DMSA is approved for the treatment of pediatric lead 

poisoning in the United States; it also has been used successfully 

to chelate arsenic in humans, and is being further evaluated for 

18 Emergency Department Management • ATSDR 
 

Arsenic Trioxide 

Laboratory Tests 

Disposition and 

Follow-up 

Delayed Effects 

this use. Water-soluble chelating agents like DMSA are less 

toxic than BAL and are often substituted when the patient’s 

condition improves. DMSA might also be preferable for patients 

with renal insufficiency, but GI motility is a prerequisite, as well 

as GI decontamination (to prevent increased arsenic absorption). 

The use of D-penicillamine as an oral chelating agent is 

controversial. It has been used successfully in children, but 

should be avoided in penicillin allergic patients. 

Routine laboratory studies for seriously exposed patients include 

CBC, serum electrolytes, urinalysis and liver enzyme and kidney 

function tests. Chest radiographs and pulse oximetry (or ABG 

measurements) are recommended for patients who have 

respiratory symptoms. An abdominal radiograph can detect 

radiopaque ingested arsenic. Additionally, 24-hour urine arsenic 

levels are useful for monitoring symptomatic patients. A chelated 

or non-chelated level above 100 μg is usually considered 

abnormal. Normal total urinary arsenic levels are less than 50 

μg/L in the absence of recent consumption of seafood that 

contains organic forms of arsenic (i.e., fish arsenic). 

A high blood arsenic level (normal being less than 7 μg/100 mL) 

might confirm a diagnosis of poisoning. However, arsenic moves 

quickly out of the bloodstream (its initial half-life in blood is 1 to 

2 hours) and a normal value does not exclude poisoning. If the 

blood arsenic level is normal, but the 24-hour urinary arsenic 

excretion is elevated, and there is a compatible clinical 

presentation, the diagnosis can still be made. 

Note: If the patient has eaten seafood containing organic arsenic 

(fish arsenic) within the past 48 hours, total urinary arsenic might 

be significantly elevated (urinary arsenic of up to 1,700 μg/L has 

been measured following a large shellfish meal). Some 

laboratories can speciate arsenic into the nontoxic organic 

arsenics found in seafood and the toxic inorganic forms, 

although results are often not quickly available. 

Hospitalize patients who have ingested a significant amount of 

arsenic trioxide, those who have had significant inhalation 

exposure, and those who require chelation therapy. 

Delayed effects can occur after an acute arsenic exposure that 

resulted in significant acute effects. Delayed effects include 

peripheral neuropathy, bone marrow suppression (anemia, 

leukopenia, pancytopenia), encephalophathy, cardiomyopathy, 

and dermatologic lesions. Although timely chelation therapy 

ATSDR • Emergency Department Management 19 
 

Arsenic Trioxide 

reduces the occurrence of delayed effects, follow-up should 

include particular attention to these organ systems. 

Patient Release	 Asymptomatic patients who have minimal exposure, normal 

initial examinations, and no signs of toxicity after 6 to 8 hours of 

observation may be discharged with instructions to seek medical 

attention promptly if symptoms develop (see the Arsenic 

Trioxide—Patient Information Sheet below). 

Follow-up	 Obtain the name of the patient’s primary care physician so that 

the hospital can send a copy of the ED visit to the patient’s 

doctor. 

Patients who remain asymptomatic after exposure require no 

follow-up. Discharged patients who had relatively minor or 

transient symptoms following an ingestion exposure should 

initiate a 24-hour urine collection for arsenic measurement. 

Follow-up should include evaluation of urinary arsenic levels, 

and consultation with the regional poison center regarding 

outpatient chelation. For severely exposed patients with 

significant symptoms of acute poisoning, follow-up evaluation of 

neurologic, circulatory, renal, pulmonary, hematologic, and 

hepatic function should be arranged. Patients who have corneal 

lesions should be reexamined within 24 hours. 

Reporting	 If a work-related incident has occurred, you may be legally 

required to file a report; contact your state or local health 

department. 

Other persons may still be at risk in the setting where this 

incident occurred. If the incident occurred in the workplace, 

discussing it with company personnel may prevent future 

incidents. If a public health risk exists, notify your state or local 

health department or other responsible public agency. When 

appropriate, inform patients that they may request an evaluation 

of their workplace form OSHA or NIOSH. See Appendices III 

and IV for a list of agencies that may be of assistance. 

20 Emergency Department Management • ATSDR 
 

Arsenic Trioxide 

Arsenic Trioxide (As O ) 2 3 

Patient Information Sheet 

This handout provides information and follow-up instructions for persons who have been exposed to 

arsenic trioxide. 

What is arsenic trioxide? 

Arsenic is an element found naturally in the environment. There are many arsenic compounds of 

commercial importance. One of the most toxic of these is arsenic trioxide. Arsenic trioxide is a white 

or transparent solid that has no taste or odor and low flammability. Arsenic trioxide is used in the 

manufacture of wood preservatives, as an insecticide and herbicide, in metallurgy, and in glass and 

ceramic manufacturing. 

What immediate health effects can be caused by exposure to arsenic trioxide? 

Breathing arsenic trioxide can cause nose and throat irritation, but generally, a person cannot inhale 

enough to severely harm internal organs. Skin or eye contact can cause irritation. 

Intentional or unintentional swallowing of even a tiny amount of arsenic trioxide can cause severe 

vomiting, diarrhea, abdominal cramps, and shock, as well as seizures; coma; damage to the liver, 

kidneys, nerves, and bone marrow; and death. 

Can arsenic trioxide poisoning be treated? 

Washing arsenical residues from the skin or eyes usually reduces the irritant effect. If arsenic trioxide 

is swallowed, measures can be taken to remove it from the body. In severe cases, medicines called 

chelating agents are given to remove arsenic from the body and eliminate it in the urine. Severely 

affected individuals must be hospitalized. In some cases, permanent nerve damage can result even if 

chelation therapy is used. 

Are any future health effects likely to occur? 

Arsenic trioxide can cause adverse health effects in the liver, kidney, brain, nervous system, or bone 

marrow for months or years after a severe poisoning. 

What tests can be done if a person is exposed to arsenic trioxide? 

Blood and urine tests for arsenic can be done to confirm exposures. In cases of ingestion, arsenic might 

show up in the intestines or stomach on x-rays. Arsenic levels in urine can be monitored to tell when 

the arsenic has been eliminated form the body. Monitoring for past or long-term exposure can be carried 

out by analysis of arsenic levels in hair or nails. 

Where can more information about arsenic trioxide be found? 

More information about arsenic trioxide can be obtained from your regional poison control center; your 

state, county, or local health department; the Agency for Toxic Substances and Disease Registry 

(ATSDR); your doctor; or a clinic in your area that specializes in occupational and environmental 

health. If the exposure happened at work, you may wish to discuss it with your employer, the 

Occupational Safety and Health Administration (OSHA) or the National Institute for Occupational 

Safety and Health (NIOSH). Ask the person who gave you this form for help in locating these telephone 

numbers. 

ATSDR • Patient Information Sheet 21 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Arsenic Trioxide 

Follow-up Instructions 

Keep this page and take it with you to your next appointment. Follow only the instructions checked below. 

[ ] Call your doctor or the Emergency Department if you develop any unusual signs or symptoms within 

the next 24 hours, especially: 

•	 vomiting, abdominal cramps, diarrhea 

•	 severe weakness 

•	 rapid heart rate 

•	 shortness of breath, coughing, or wheezing 

•	 increased pain or discharge from injured eyes 

[ ] No follow-up appointment is necessary unless you develop any of the symptoms listed above. 

[ ] Call for an appointment with Dr. in the practice of . 

When you call for your appointment, please say that you were treated in the Emergency Department at 

Hospital by and were advised to 

be seen again in days. 

[ ] Return to the Emergency Department/ Clinic on (date) 

at AM/PM for a follow-up examination. 

[ ] Do not perform vigorous physical activities for 1 to 2 days. 

[ ] You may resume everyday activities including driving and operating machinery. 

[ ] Do not return to work for days. 

[ ] You may return to work on a limited basis. See instructions below. 

[ ] Avoid exposure to cigarette smoke for 72 hours; smoke may worsen the condition of your lungs. 

[ ] Avoid drinking alcoholic beverages for at least 24 hours; alcohol may worsen injury to your 

stomach or have other effects. 

[ ] Avoid taking the following medications: 

[ ] You may continue taking the following medication(s) that your doctor(s) prescribed for you: 

[ ] Other instructions: 

•	 Provide the Emergency Department with the name and the number of your primary care physician so 

that the ED can send him or her a record of your emergency department visit. 

• You or your physician can get more information on the chemical by contacting: 

or , or by checking out the following Internet 

Web sites: ; . 

Signature of patient Date 

Signature of physician Date 

22 Patient Information Sheet • ATSDR