Understanding your pet’s health is very vital. But in many instances, when older dogs take less medication than is indicated by their weight. If your senior must be put on medication for any reason you must watch for side effects. If you do notice reactions, your veterinarian will either reduce the amount or change the medication. Personally, I don’t like giving medication to anyone, but if necessary, it is a good idea. If on thyroids, it must be lowered as he ages. Most people don’t know this and it could negatively affect their health by miles.