Puppy’s can start the heartworm prevention medication at 8 weeks old. Thereafter once every month it should be given.
An 8 wk old pup can start on the heart worm medication as long as the weight factor is considered and the brand chosen allows for the weight and age. Many brands vary for weight and age of young pups. It’s best to rely on your veterinarians expertise to offer you the appropriate brand for the breed, age and weight for your individual puppie.
See more articles under “Before you go to the Vet”.