Sheltie Nation

Seizures and Heartworm Medications in Shelties

QuestionThank goodness seizures in Shelties is not a common problem. However, as responsible Sheltie owners, we should be aware of the things that can CAUSE seizures in Shelties:

- Sudden high fever.
- Certain illnesses.
- The ingredient in some Heartworm Medications.

If you own a Sheltie, you probably know by now that this is a very sensitive breed. Things that wouldn’t normally affect most dogs can affect a Sheltie. Ivermectin, the ingredient in Heartguard is one of those things that MAY cause seizures in a Sheltie.

Heartguard is a wonderful and very effective product that has saved countless dogs from getting heartworm. However some Shelties and Collies react very adversely to Heartguard. If you are using Heartguard and you notice your Sheltie having seizure(s) every month, this may be the culprit.

If your Sheltie’s seizures are caused by the Ivermectin in Heartguard, most often switching to a different Heartworm Preventative will solve the problem. Intercepter or Sentinal are both good alternatives.

Heartworm Preventative is VITAL in protecting your Sheltie from a deadly heartworm infestation, and should not be discontinued under any circumstances. If you suspect your Sheltie may be experiencing monthly seizures that coincide with your monthly heartworm pill, please talk to your vet and ask him/her to work with you on checking out this possibility.

It is also important to note that several years ago, the formula in Heartguard was changed and relabeled as “now safe for Shelties and Collies”. And while the new formula did help matters considerably, Shelties still CAN react to it.

To be sure if ivermectin is safe for your Sheltie, you can now have them DNA tested. This simple test can tell you if your Sheltie or Collie carries the gene that would cause the reaction. You can learn more about the test by visiting the Washington State University website.

The information on this page is solely intended to help owners who are struggling with seizures in their Shelties. It is NOT intended in any way to discourage the use of Heartguard in other dog breeds, or in Shelties who are not having seizures. (If your Sheltie has been using Heartguard and has not had a problem with seizures, there is no reason to switch medications. Trevor used it every month without a problem. However, our new puppy Teddy did have a mild reaction, so he will no longer get ivermectin drugs.)

Thanks again to Angie of the All Shelties store for the use of little Shelby’s photo!

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