Vitamin D, found in multivitamins and many flavored chewable vitamins such as Viactiv, can cause toxicity when accidental ingested by pets. Vitamin D is also found in some rodenticides (as cholecalciferol) and carries a higher toxicity risk than OTC products. The most concerning outcome with ingestion is acute renal failure.

Signs and symptoms of toxicity: Clinical signs of toxicity usually appear within the first 48 hours post-ingestion. These signs and symptoms include vomiting, fatigue, muscle weakness, bloody diarrhea, depression, increased urination and increased thirst.

Toxic consumption: There is no established threshold for toxicity. All incidents of exposure should be reported immediately.

References:
Morrow, C. (2001). Cholecalciferol Poisoning. Veterinary Medicine (December): 905-11.