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 also 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”), which was widely used in previous centuries as an emetic and purgative. 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 or furnace slag is treated with acid.
Mechanism of toxicity. The mechanism of antimony and stibine toxicity is not known. Because these compounds are chemically related to arsenic and arsine gas, respectively, their modes of action may be similar.
Antimony compounds probably act by binding to sulfhydryl groups, enhancing oxidative stress, and inactivating key enzymes. Ingested antimonials are also corrosive to GI mucosal membranes.
Stibine, like arsine, may cause hemolysis. It is also an irritant gas.
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 3200–4000 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.
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.
Acute ingestion of antimony causes nausea, vomiting, hemorrhagic gastritis, and diarrhea (“cholera stibie”). Hepatitis and renal insufficiency may occur. Death is rare if the patient survives the initial gastroenteritis. Cardiac dysrhythmias (including torsade de pointes), pancreatitis, renal failure, aplastic crisis, and arthralgias have been associated with the use of stibogluconate for the treatment of parasitic infections.
Acute stibine gas inhalation causes acute hemolysis, resulting in anemia, jaundice, hemoglobinuria, and renal failure.
Chronic exposure to antimony dusts and fumes in the workplace is the most common type of exposure and may result in headache, anorexia, pneumonitis/pneumoconiosis, peptic ulcers, and dermatitis (antimony spots). 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).
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.
A suspected causal link between antimony and the sudden infant ...