Antacids in the initial management of metallic zinc ingestion in dogs

Zinc poisoning in dogs, following ingestion of post-1982 U.S. one cent coins is an increasingly common toxicological syndrome causing gastrointestinal abnormalities, hemolytic anemia, pancreatitis and renal failure. Thermodynamic laws predict that the rate of the chemical reaction between HCl and metallic zinc, which releases absorbable zinc anions, is dependent on pH. The significance of the relation between pH and dissolution is, however, apparently contradicted by the fact that recent veterinary toxicology texts are silent on the use of antacids in the early management of zinc ingestion in dogs. A series of experiments were conducted to test the hypotheses that the degree to which zinc dissolution is pH dependent is likely to be of clinical importance and that the use of antacids will be of benefit in preventing zinc poisoning in dogs that had ingested metallic zinc. Zinc dissolution was strongly dependent on pH in an exponential manner, indicating that clinically achievable upward adjustment of gastric pH using antacids is likely to have significant effects on the rate of zinc absorption in dogs. These data clearly support the use of antacids during the initial treatment of metallic zinc ingestion in dogs.