I agree with Ladymom. They should be checked once a year for heartworm, if you are doing that, they should ok the medicine from 1800petmeds. The price on the internet is almost half what the vet charges, I think the vets mark up the price considerably. A vet will require that you test every 6 months (for a year) if their records show that you have not purchased the medicine from them, from another vet, or they have authorized the purchase over the internet. They need to make sure the dog has not gone unprotected.
If that is not the case and this is just about them making it difficult for you to purchase elsewhere, I would seriously consider either speaking with the vet or making a change. The important thing is that the dog is getting the medicine, it should not matter if you buy from the vet or the online provider.
