There are guidelines we must follow in order to legally dispense heartworm prevention. Heartworm medication is for our current patients that have a current (according to our policy) heartworm test on file. A puppy that comes to an event under six months of age can begin monthly heartworm prevention without a test. The puppies that begin prevention with us, under 6 months of age, will be tested when the 2nd rabies is given, usually around 15-18 months of age. Any dog, over 6 months of age, that has not been on prevention consistently would need a test prior to purchasing prevention. Our policy states we will heartworm test our patients every other year as long as we have records showing consistent monthly prevention being administered in the proper weight range (even in the winter). If there are missed doses, we reserve the right to test early. Your pet may need to change the brand of medication depending on the circumstances. Any questions may be directed to the floor manager at an event.