German Shepherd dog

Years ago when I first used Ivermectin its was for fox's, there were two kind's , injectable, one for swine and one for bovine.

Its was only used in very small dose's or risk permanent damage to internal organ's and reproductive system's.

It was supposed to kill anything that fed on blood, parasite's internal and external.   It was expensive due to the size of the bottle's available from vet supply house.

The dosage is the key to its effectiveness.  Too little no result's , too much and organ damage.

I stopped using the injectable.    I'm using Interceptor now for heartworm's and have tried heartgard, I prefer the Interceptor and heard from a vet problem's with the effectivness of the heartgard. 

I worm separately for hook, whip, and roundworm once per year in adult's and twice the first year with pup's.

I am a huge fan of Sentinal.  I get it very well priced, because of the clinic where I work. 

With Sentinal, you should not have to worm for anything---it covers intestinal parasites, including whip worms.

It also has the product that kills fleas.  Which I really like.

I use Ivermectin if I have a rescue in with Mange----it is great for that.  Ear mites too!

also NEVER use ivermec internally for cats as a wormer... I've used it to treat earmites, but dabbing a Qtip in the paste and painting the inside of the ears... but if injested can cause really horrible neurological problems in cats.

Actually, Dog Trainer, I had a bitch have a fecal with ONE hookworm egg in her stool while on Sentinel.
Of course,considering what she was already on and that I'm used to seeing negative fecals, I flipped out. My vet explained it like this: these things are given as prevantative measures; but if by chance a dog is exposed directly to something, then there's no guarantee that the dog may not STILL pick it up-it's just to lessen the severity. Same with vaccinations; we have our dogs vaccinated in the hopes of preventing disease; but if directly exposed/in contact with such, the dog might come down with a light case of it anyhow, despite vaccinating. Made sense, but didn't exactly make me happy about it. They told me to consider and still do a Panacur worming every once in a while to make sure nothing has happened in the meanwhile. We've never had another showing of such in a fecal.

And yes, Ivermectin will react negatively with cats, and will react also with longer coated GSDs if you're not careful. Seen it both. My long-coat solid black male would get terribly SICK when he was given Heartgard, so we stopped it and switched to Sentinel. He didn't seem to mind the Sentinel.