Intercepter vs. Heartgaurd

I can't get a straight answer from my vet either.  She's stopped selling Hartguard to her clients recently.  the best I could do was one of the front staff said some of their clients' dogs were having "problems".

Since I've got two dogs that are sensitive to milbemycin, I treat with invermectin injectable in an oral dosage I got from my vet.  If I didn't have ten to twelve dogs here at any one time, I would purchase Hartguard (or the generic now available) online with a prescription from my vet. I probably would not use the "plus" version and instead would continue to treat for intestional parasites seperately - especially since what I heard is that the "plus" version is what my vet is questioning in particular.

Again, I don't have any info other than that.  I've been using Ivermectin safely for years so I'm confident it, at least, is not a problem.

Most likely because Interceptor controls intestinal parasites as well as heartworms, while Heartgard only control heartworms.  (Heartguard Plus is a combination of two drugs - ivermectin and pyrantel pamoate - and doensn't seem to be as popular as an "all in one" like milbemycin oxime)

I have two dogs that are sensitive to ivermectin, so I'm happy that my vet carries Interceptor.

My understanding is that Interceptor kills one more type of worm/parasite than Heartguard does.  Whether that's the reason your vets switched, no idea.  But I choose Interceptor when given the choice.

It could have nothing to do with the product and everything to do with the "free stuff" or the cost the company charges the clinic to flog their product. But who knows!
 
I use Interceptor because it's safe for my bitches when they are pregnant and nursing. []

Ahh - I found it.
Heartguard prevents heartworms (kills at different larva stages - L4 & L5, than Interceptor) and also "controls" roundworms and hookworms.
 
Interceptor prevents heartworms (L3 & L4) and also controls roundworms, hookworms, and whipworms. 

I think there was some sort of issue with some dogs being allergic to the ingredients in the "treat" part of Heartgard. I'm not positive but I remember hearing something about it. Could totally be hearsay.