Pet medicine for younger dogs, those dogs between the ages of one and 7 years of age, are specially formulated for adult dogs. They are not meant for puppies or mature dogs, meaning the dogs over 7 years of age. Those dogs are considered to be mature or senior. A dog that is one year old has finished with his puppy shots and will only need medications if something is wrong with him or his monthly preventative pills.
Different breeds of canines under one year of age also may require a different strength of the same type of prescription or non-prescription pills. For example a Great Dane puppy would need a stronger dose of a dewormer than a Yorkshire terrier or any of the teacup size puppies. A difference in size means a difference in the proportion of medications.