This general cellular poison can affect all species of animals. It has been banned for use as a rodenticide. Onset of clinical signs may be delayed 1–3 days and, although all body systems are affected, the most prominent signs are of the GI, respiratory, integumentary, and nervous systems. Signs include gastroenteritis (occasionally hemorrhagic), abdominal pain, dyspnea, blindness, fever, conjunctivitis, gingivitis, and tremors or seizures. After 4–5 days and an apparent recovery, or after repeated small doses, a chronic dermatitis characterized by alopecia, erythema, and hyperkeratosis occurs. Necrosis of many tissues is a common necropsy finding.

Treatment of the acute phase of thallium poisoning includes emetics, gastric lavage with a 1% sodium iodide solution, and IV administration of 10% sodium iodide. Diphenylthiocarbazone (dithizone, 70 mg/kg, PO, tid) is antidotal but must be given within 24 hr of exposure. At the same time and for 14 days thereafter, Prussian blue 100 mg/kg should be given bid in oral aqueous suspension to stop enterohepatic recirculation of the thallium and to enhance its excretion in the feces. Symptomatic treatment of the diarrhea and convulsions is needed with particular attention to fluid and electrolyte balance, nutrient needs, prevention of secondary infection, and good nursing care.

Last full review/revision March 2012 by Frederick W. Oehme, DVM, PhD