Only one vet here in town sells this. I switched on their recommendation bc it is a preventative for more than just heartworms. However, it doesn't always work, and my dogs picked up another worm, most likely from eating horse manure. The company reimburses for the fecal sample and medication, though. It is still effective for the heartworms, juts not great for other worms when your dogs are frequently sneaking horse apples. It is a small chewable pill that looks unappealing, but the dogs love them.

Pros: kills other types of worms also

Cons: availability

I began using Interceptor for one of my dogs when he had bad reactions to Hartguard (diarrhea, vomiting, etc.). We have never had a problem on Interceptor and he has not gotten heartworms, so it appears to be effective. It is a small pill that he eats readily when it is hidden in his dinner, but it is not a tasty treat like Hartguard, either. I give it to him with a meal to reduce stomach upset.

Pros: seems to work, easy on stomach

Cons: (none)

If you have ever dealt with whip worms -- they live forever in the soil and can infect a dog at any time. The dog gets the worm when grooming after walking on infected soil. Interceptor takes care of the worm before it infects the dog. Great stuff

Pros: kills several paracites

Cons: none

My dogs have been on this medication for a decade now. We originally started this for whipworms which are extremely hard to get rid of in the yard. Comes in different strengths according to the dogs weight. Also, stickers are available to put on the calendar to remind you of the next month's due date. Company offers yearly $10 rebates per dog.

Pros: chewable form

Cons: dog has to be tested yearly, medicate each month

This is the only heartworm preventative I have ever used for my dogs. They like the flavored tablets and don't mind taking them at all. They think it's a treat. I recommend interceptor to anyone who has problems getting their pets to take medication.

Pros: taste good

Cons: none