One of my clients let me know that his 13 year old yorkie randomly started having seizures & when he was taken to the vet, they suggested it might have been from the Simparica Trio chewable pill. When he looked over the side effects, they were diarrhea vomiting & seizures(with or without a history of seizures.) Make sure you’re looking into what we’re giving our pets, in my opinion I don’t think the side effects are worth the purpose of the pill (flea, tick & heartworm prevention.)