Like most dog owners who trust their vet, Ashley Sassaman didn't hesitate to follow her vet's suggestion that her two dogs, Jack and Katrina, be given a new heartworm preventative, ProHeart6, at their last wellness check up. The convenience of a shot every six months instead of remembering to give monthly medication was a big selling point for the working mom. A week after the shot, Jack grew lethargic. He no longer wanted to play fetch or go for walks. The family brought him back to the vet, but she couldn't find an explanation for the behavior change. Three weeks after the shot, they found Jack dead at home. Ashley began to ask questions - ones that she wishes she had asked before Jack received the shot - and discovered that the FDA had briefly taken ProHeart6 off the market due to adverse reactions, including death. Also, Pfizer, the company that made ProHeart6, advised vets that they should discuss possible side effects with the dog's owners, and have them sign an "Owner Consent Form" before the first injection, a protocol that Ashey's vet did not follow. Ashley has since changed vets and Pfizer offered to pay for Jack's necropsy. It is her hope that sharing Jack's story will encourage other dog lovers to ask questions and do research in order to keep their dogs healthy and safe.