I use Interceptor..it cost about 35.00 for a year supply...according to my vet (I'm in NY)...Maximus will have to take it for the rest of his life...but the cost of PREVENTING it is minimal to the cost of treating it and is very bad for the dog...I think it is a good idea...you can also get Revolution which combines the benefits of frontline plus heartworm..I am not sure on the cost though
