One of the main causes of poisoning of small animals is exposure to drugs intended for human use. Poisoning may result from misuse by pet owners, off-label use of medicines or, more frequently, accidental ingestion of drugs that are improperly stored.
Dogs are most commonly affected. The major drugs involved include:
Any human medicine can cause serious illness or even death to small animals, so owners should keep these medicines out of reach from their pets.
Via: http://www.sciencedirect.com/science/article/pii/S109002331400450X