Is Heartgard safe for my Australian Shepherd? What about flea/tick?

Hi there. The concern with Australian Shepherds is that many dogs of this breed may carry the MDR1 gene mutation, which makes them especially sensitive to certain medications. Frontline (active ingredient fipronil) is NOT a drug that would be expected to cause any problems in these dogs, so in general it is fine to use in Aussies.

Hi there. 68 mcg is the normal dose of Heartgard for a puppy up to 25 pounds, so Beau should be just fine :) Even if he is MDR1 positive (the gene that makes some dogs more sensitive to ivermectin), normal Heartgard doses are still completely safe for these dogs. They can have difficulty with higher ivermectin doses that are sometimes used to treat certain types of mange and other problems, so we do have to be careful with this type of treatment in herding breeds - but regular Heartgard is such a low dose that it's still perfectly safe.

Flea and tick drugs are not toxic if used responsibly at acceptable doses. Shepherd breeds should ways use these drugs with care due to the possible presence of the MDR gene, a genetic component that can cause oversensitivity to some drugs. Other products that are natural that have been shown to have some repellant and insecticidal activity include coconut oil and cedar oil.

Side effects are generally very rare in heartworm preventative medications, but are certainly possible. I have attached a handout below that discusses the different heartworm preventative products. https://www.veterinarypartner.com/Content.plx?P=A&S=0&C=0&A=488 As you can see, there are a huge number of products on the market. Some herding breed dogs (such as Blue Heelers and Australian Cattle dogs) will be sensitive to ivermectin (the active ingredient in Heartgard), so I would discuss your other heartworm preventative options with your veterinarian. I have been very pleased with Interceptor or Sentinel for herding breed dogs. Good luck! I hope that was helpful. Thanks for using PetCoach.

Thank you for contacting Petco Pet Education Center, formerly Petcoach with your question about Timo. Great question! You are correct that collies can be more susceptible to ivermectin, which is one of the main ingredients in Heartgard. That being said, this lethargy, loss of appetite, and vomit can all be normal side effects of the Heartgard. If he carried the gene that made him sensitive to ivermectin, I would expect to see a reaction every time he was given it, not just on occasion. I do suspect that it's normal side effects, but you should check with his vet just to be safe. The Bravest will be fine. I hope this helps!

It's actually perfectly safe to use Heartgard (which has the active ingredient ivermectin) as a heartworm prevention if you like. It's true that Old English Sheepdogs and other herding breeds can sometimes have a genetic mutation (the mdr1 mutation) that makes them more sensitive to certain drugs, including ivermectin - this means that it might not be safe to use high doses of this drug in these breeds, such as the doses often used to treat scabies or demodectic mange. But at the very low doses used in Heartgard and other heartworm preventatives, these breeds have no issues at all - so it's fine to use this product if you like. If you're still concerned and want to choose a different drug entirely, Sentinel is another very effective heartworm preventative that has a different active ingredient (milbemycin oxime) which should not cause any issues at all.

Technically, all heartworm preventatives (even those with ivermectin) are safe in dogs with an MDR1 gene mutation since the effective dose of medication in heartworm is significantly lower than that which would cause neurotoxicity. However, most vets will preferentially choose selamectin (Revolution) or milbemycin (Interceptor) based products for MDR1 mutant dogs over ivermectin (Heartgard) based products. If Tasha has historically been very sensitive to heartworm preventatives, I would advise giving her flea/tick prevention and heartworm prevention 2 weeks apart rather than simultaneously. Your vet will be able to perform a blood test for heartworm disease prior to starting Tasha on a heartworm preventative, as all are prescription based.