Just like humans, some pets need heart medication that helps regulate blood pressure. These medications can only be prescribed by a vet. Not treating and regulating your pet's blood pressure can result in serious, and even deathly, consequences. There are many kinds of medication that can be used to treat their blood pressure, and the right one should be prescribed by your vet. For example, Atenolol is a beta-blocker it is used to treat heart conditions such as arrhythmias and can help lower blood pressure in dogs.