[Ellie May]

It's probably just fine.

I prefer Merial and Novartis to Virbac, so automatically their heartworm preventatives will win with me. Virbac is the company that has decided it's okay to put xylitol in a dog tooth cleaning product. I do use their toothpaste, but I'd personally just rather go elsewhere for heartworm if possible.

I only pay like $55 for 12 months of Interceptor. It covers more parasites than ivermectin/pyrantel (there is nothing wrong with iver/pyr products by any means, but we all have our preferences). This could be important for a dog who is outside a lot, esp. if fecals aren't done often.

It's really up to you.