Preventive health is where most of a dog's lifetime medication plan actually begins — heartworm prevention, flea and tick control, intestinal parasite protection, vaccine timing, dental care, and the routine screenings that catch problems before they become prescriptions. This section gathers pharmacist-reviewed guidance on what to give, when to give it, and how to keep a protocol on schedule year-round, including the drug classes and dosing considerations behind common preventives. It's written for owners managing a healthy dog they intend to keep that way, and for those piecing together a prevention routine after a lapse, a move, or a new puppy in the house.