Zinc phosphide

From Dog

Zinc phosphide and aluminum phosphide are rodenticide poisons used to control vermin[1].

Accidental poisonings in dogs is uncommon compared to anticoagulant rodenticides and commonly occur on farms from ingesting treated bait or the carcasses of poisoned rodents[2].

Toxicity is due to liberation of phosphine gas at the acid pH in the stomach. The gas results in direct GI tract irritation along with cardiovascular collapse.

The toxic dose is ~40 mg/kg, and onset is rapid in animals with a full stomach[3].

Clinical signs include vomiting, abdominal pain, and aimless running and howling, followed by depression, dyspnea, and convulsions[4].

Diagnosis is based on history of exposure, clinical signs, and detection of zinc phosphide in stomach contents.

Treatment includes intravenous fluid therapy, calcium gluconate, and appropriate fluids to reduce acidosis, as well as induction of emesis with apomorphine, gastric lavage and activated charcoal administration.

Caution should be exercised by veterinarians due to the toxic nature of this chemical[5].

References

  1. Stowe CM et al (1978) Zinc phosphide poisoning in dogs. J Am Vet Med Assoc 173(3):270
  2. Guale FG et al (1994) Laboratory diagnosis of zinc phosphide poisoning. Vet Hum Toxicol 36(6):517-519
  3. Gray SL et al (2011) Potential zinc phosphide rodenticide toxicosis in dogs: 362 cases (2004-2009). J Am Vet Med Assoc 239(5):646-651
  4. Merck Veterinary Manual
  5. Centers for Disease Control and Prevention (CDC) (2012) Occupational phosphine gas poisoning at veterinary hospitals from dogs that ingested zinc phosphide - Michigan, Iowa, and Washington, 2006-2011. MMWR Morb Mortal Wkly Rep 61(16):286-288