Dog collapsing, shaking monthly: Could it be heartworm or flea meds?
Updated On September 23rd, 2025
Pet's info: Dog | Mixed Breed Large (61lb +) | Male | neutered | 65 lbs
My dog is having an episode once a month that looks like ataxia and I'm trying to find a cause. Can it be caused by invermectin or other chemicals in his heartworm medications heartguard, tri-heart or his flea/tick meds usually a topical frontline or others? His symptoms include loss of motor function (he collapsed on the floor and cant walk or stand for 5-7 minutes), shaking all over his body, and his eyes seem to not be to concentrate on any particular thing.
4 Answers
Most Helpful Answer
Published on June 20th, 2017
If the episodes occur in close proximity to administration of one of these products (24-48 hours) then it could be related to the medication. In these cases the product should be stopped and the pet should be transitioned to a different one. Another potential cause could be a type of seizure. You did not mention an age for Max, but seizures in dogs can be due to epilepsy (typically diagnosed at a young age but can be diagnosed later in life), metabolic cause (hypoglycemia, Addison's disease), central nervous system infections/inflammation, or an intracranial mass (typically more of a concern in older patients). If he has not had a full physical exam performed recently by his veterinarian I would recommend having it done, along with routine wellness blood work (serum chemistry, complete blood count) to rule-out organ dysfunction/metabolic cause.
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Related Answers from Veterinarians
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Published on January 20th, 2018
Hello. Sorry to hear this happened to Timmy. What you are describing is seizure activity. You need to get him to a vet as soon as possible for evaluation. Seizures can be caused by any number of underlying conditions - anything from epilepsy to a liver issue to a brain tumor. Some testing will be needed to figure this out. Here is a link to an article about seizures in dogs. https://vcahospitals.com/know-your-pet/seizures-general-for-dogs Hope this helps. Best wishes.
1Pet Parents found this answer helpful
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Published on April 22nd, 2017
This sounds like you could be describing a seizure. Most seizures are characterized by an 'ictal' phase where the dog loses consciousness and has convulsions or muscle rigidity. Sometimes the loss of consciousness isn't as obvious. After this more active phase is the 'post-ictal' period where the brain is recovering from the seizure. Dogs seem disoriented, have difficulty walking or can even act blind for a few minutes to hours. Seizures can be caused by a number of different problems in the brain, trauma, or epilepsy. Some toxins, low blood sugar, or major electrolyte changes can also cause seizures or similar symptoms. I would recommend having Broncco seen by an emergency veterinarian to make sure he seems neurologically normal. If there is nothing concerning on his exam, they may recommend monitoring him at home for future episodes. If another episode does occur it can be very helpful to take a video if possible.
1Pet Parents found this answer helpful
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Published on March 24th, 2017
It sounds as though your dog experienced a seizure if he had abnormal repeated movements, urinated and seemed a bit "off" for a few minutes afterwards. This may very well be a one time occurrence, but if it happens again, take a video to show to your vet. There are a wide variety of causes of seizures, including epilepsy, liver disease, brain tumors, etc. As long as your dog is acting normally tonight and not experiencing other abnormal behaviors/movements, there is no need to rush to a vet. However, if he experiences another episode tonight, he should be seen because these are referred to as "cluster seizures".
2Pet Parents found this answer helpful
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