Antimony (Sb) is a versatile trace element widely used for hardening soft metal alloys; for compounding rubber; as a major flame retardant component (5-20%) in plastics, textiles, and clothing; and as a coloring agent in dyes, varnishes, paints, and glazes. Exposure to antimony dusts and fumes may occur during mining and refining of ores, in glassworking, and from the discharge of firearms. Organic pentavalent antimony compounds (sodium stibogluconate and antimoniate meglumine) are commonly used worldwide as antiparasitic drugs. Foreign or folk remedies may contain antimony potassium tartrate (“tartar emetic” or trivalent antimony), which was widely used in previous centuries as an emetic, purgative, and aversive therapy for alcohol abuse. Stibine (antimony hydride, SbH3) is a colorless gas with the odor of rotten eggs that is produced as a by-product when antimony-containing ore is exposed to acid.

The mechanism of antimony and stibine toxicity is not completely known. Because these compounds are chemically related to arsenic and arsine gas, respectively, their modes of action may be similar.

1. Antimony compounds probably act by binding to sulfhydryl groups, enhancing oxidative stress, and inactivating key enzymes in multiple organs. Ingested antimonials are corrosive to GI mucosal membranes and demonstrate significant enterohepatic recirculation.
2. Stibine, like arsine, may cause hemolysis. It is also an irritant gas.

1. An estimated toxic amount of the organic antimony compound tartar emetic (nonelemental antimony) is 0.1-1 g. The lethal oral dose of metallic antimony in rats is 100 mg/kg of body weight; the trivalent and pentavalent oxides are less toxic, with LD50 in rats ranging from 3,200 to 4,000 mg/kg of body weight. The recommended workplace limit (ACGIH TLV-TWA) for antimony is 0.5 mg/m³ as an 8-hour time-weighted average. The air level considered to be immediately dangerous to life or health (IDLH) is 50 mg/m³.
2. The recommended workplace limit (ACGIH TLV-TWA) for stibine is 0.1 ppm as an 8-hour time-weighted average. The air level considered immediately dangerous to life or health (IDLH) is 5 ppm.

1. Acute ingestion of antimony causes nausea, vomiting, hemorrhagic gastritis, and diarrhea. Hepatitis, renal insufficiency, and prolongation of the QTc interval may occur. Cardiac dysrhythmias (including torsade de pointes), hyperkalemia, pancreatitis, aplastic crisis, and arthralgias have been associated with the use of antimonial antiprotozoal drugs, such as stibogluconate, for the treatment of parasitic infections.
2. Acute stibine gas inhalation causes acute hemolysis, resulting in anemia, jaundice, hemoglobinuria, and renal failure.
3. Chronic exposure to antimony dusts and fumes in the workplace is the most common type of exposure and may result in headache, anorexia, respiratory tract and eye irritation, pneumonitis/pneumoconiosis, peptic ulcers, and dermatitis (“antimony spots”). Autoimmune reactions (cutaneous hypersensitivity or systemic sclerosis) have been associated with meglumine antimoniate. Sudden death presumably resulting from a direct cardiotoxic effect has been reported in workers exposed to antimony trisulfide. Based on evidence of in vitro genotoxicity and limited rodent carcinogenicity testing, antimony trioxide is a suspected carcinogen (IARC 2B).
   1. In 2009, the Centers for Disease Control and Prevention (CDC) investigated a cluster of nonspecific neurologic symptoms among firefighters in Florida, concluding that antimony-containing flame retardant uniforms did not cause clinical or laboratory changes consistent with antimony toxicity.
   2. A suspected causal link between antimony and the sudden infant death syndrome (SIDS) has been refuted.

Is based on a history of exposure and typical clinical presentation.

1. Specific levels. Urine antimony levels are normally below 2 mcg/L in unexposed persons and below 10 mcg/L in exposed workers. Serum and whole-blood levels are not reliable and are no longer used. Urine concentrations correlate poorly with workplace exposure, but exposure to air concentrations greater than the TLV-TWA will increase urinary levels. Urinary antimony is increased after firearm discharge exposure. Hair analysis is not recommended because of the risk for external contamination. There is no established toxic antimony level after stibine exposure.
2. Other useful investigations include CBC, plasma-free hemoglobin, serum lactate dehydrogenase (LDH), haptoglobin, electrolytes, BUN, creatinine, urinalysis for free hemoglobin, liver aminotransferases, bilirubin, ammonia, prothrombin time, cardiac injury biomarkers including troponin, and 12-lead ECG. Chest radiography is recommended for chronic respiratory exposures.

1. Emergency and supportive measures
   1. Antimony. Large-volume IV fluid resuscitation may be necessary for shock caused by gastroenteritis. Electrolyte abnormalities should be corrected, and intensive supportive care may be necessary for patients with multiple-organ failure. Perform continuous cardiac monitoring and treat torsade de pointes if it occurs.
   2. Stibine. Blood transfusion may be necessary after massive hemolysis. Treat hemoglobinuria with fluids as for rhabdomyolysis.
2. Specific drugs and antidotes. There is no specific antidote. British anti-lewisite (BAL; dimercaprol), dimercaptosuccinic acid (DMSA), and dimercaptopropanesulfonic acid (DMPS) have been proposed as chelators for antimony, although data in human poisoning are conflicting. Chelation therapy is not expected to be effective for stibine. Case reports have described the use of NAC (N-acetylcysteine) to facilitate the conjugation of trivalent antimony to glutathione.
3. Decontamination
   1. Inhalation. Remove the patient from exposure, and give supplemental oxygen if available. Protect rescuers from exposure.
   2. Ingestion of antimony salts. Activated charcoal is probably not effective in light of its poor adsorption of antimony. Gastric lavage may be helpful if performed soon after a large ingestion.
4. Enhanced elimination. Hemodialysis, hemoperfusion, and forced diuresis are not effective at removing antimony or stibine. Exchange transfusion may be effective in treating massive hemolysis caused by stibine.