This page from the American Working Collie Association has lots of excellent information regarding the gene mutation (mdr1-1delta) that makes collies sensitive to ivermectin and other related drugs. It's the source of information I've relied on for years for sensible information on the topic.

All herding breeds that have descended from (or are otherwise related to) collies have the potential to carry the mutation. However, it should be noted that the last I heard on another list (border collie related) no border collies that have been tested have been found to carry the mutation. That doesn't mean every individual in the breed is free of the mutuation, just that none of the dogs tested so far has been found to have it. CJS has already posted the link to the WSU CVM, but here is a relevant quote from there:


If you read closely the AWCA link I posted, you will see that milbemycin oxime is in the same class of drug as ivermectin: the avermectins. Any of the drugs in this class could cause an adverse reaction in dogs with the mutation, and a list of some of the more common ones is listed on that page.

I have not tested my border collies for the mutation and I do give them ivermectin (at a low dose suitable for HW prevention but not for control of intestinal parasites; incidentally, the doses that work for HW prevention are way below the dose threshold known to cause problems in dogs with the mdr1-1delta mutation, which is one of the reasons I don't test my dogs) monthly. Like Becca, I start my pups on Interceptor and then switch them over at about 8 months to a year. One of the reasons I don't like Interceptor is that I don't necessarily think it's a good idea to continually dose dogs for intestinal parasites. As a sheep farmer, I see how resistance of worms to dewormers develops and I can't help but think that using medications like that (basically continuous dosing) is just setting us up to create superparasites. I think using Interceptor on a low-dose regimen is a wise idea.

I'm sure some of you already know all of the information posted here, but I think it's helpful for people new to the topic to have as much information as possible. I think the Working Collie Association site is invaluable, especially considering the fact that it points out the other drugs of the same class that could cause problems in dogs with the mutuation.

J.

No, there isn't. There is only a 'low dose' for Interceptor because that's loaded up with way more milbemycin oxime than is needed to control only heartworm. My understanding is that the ivermectin dose in Heartgard is not similarly inflated.

I *do* believe that you can give Heartgard at 45-day intervals; a vet told me that several years ago. She said that the 30-day dosing schedule is calculated to be absolutely sure that owners get the dogs dosed, and that either preventive will be as effective given at 6-week intervals. She said that it might even be effective at 60-day intervals but she wasn't comfortable recommending that to clients. Take that FWIW.

Heartgaurd info:
http://www.b-naturals.com/newsletter/category/heartworm/

How much is in the one for 10-pound dogs?

I'm just wondering how much Interceptor to give doing the Safeheart dosage. My guy is in the same weight range. Going to the vet tomorrow hoping I can't get some info.

Thanks...

The breakdown is 0-10 (brown), 11-25 (green), 26-50 (yellow), 51-100 (white).

Thanks so much colliewog!!
I had 217 views from the time I posted my question and only your reply.
I appreciate your response.

I don't think people knew what you were looking for. Those are the weight ranges it is prescribed for.

If it helps, the green (what I use for my three 55-75 lbs) is 5.75mg. You'd still need to do the math to figure out which one you need.

Thanks colliewog - I got the brown box.
The vet was very interested in the Safeheart information.
I printed out the FDA form and she asked to keep it and show it to the holistic vet on staff.
She was ok with using the Safeheart dosage for him.

The people at the desk were like "you're getting the wrong dosage for his weight range" - I said no it's ok that's the size I want.

Also had the Snap-4 test done which was negative.

Yeah, I have to tell them every time. They look at the box and say "Oh he gave you the wrong size" so I just respond "I give them the lower dose that takes care of HWs only - the Dr didn't make a mistake."