Is monthly heartworm treatment the best approach for your dog?

Carson, our 11 year old border collie/greyhound mix recently had a bad reaction to Heartgard.  Within 12 hours of giving him a dose he was disoriented, weak in his legs (primarily back legs), having body quivers, having trouble eating & walking with his back hunched up.  

We checked in with our two vets who said it was highly unlikely that these symptoms were related to Heartgard.  One vet said we could do a MDR1 (multidrug resistance gene) test.  Our vets never told us that certain breeds can have the MDR1 gene & that a test was available…..

The MDR1 gene is common in herding breeds & mixed herding breeds. Due to this genetic defect dogs are not able to properly process certain medications including Ivermectin which is in Heartgard.

Carson was showing  signs of improving on day 2, he plateaued on days 3 & 4.  By day 5 he started to decline with his mobility getting worse & symptoms getting worse.  He also stopped drinking water on his own.

In the days following the dosing, we had researched holistic vets.  We also found a ton of articles about dogs having issues with Ivermectin & Trifexis, a heartworm/flea combo treatment which we had Carson on for a short time about 5 years ago before he started having seizures/dizzy spells.  

There are several articles on Trifexis which is known to have very serious side effects including death in dogs even though it is FDA approved.  We did a ton of testing at UC Davis 5 years ago which showed nothing conclusive. The UC vet recommended switching to Heartgard & Carson has been on phenobarbital ever since then to control his seizures.

Side note: Carson had not shown prior negative reactions to Heartgard dosing but we also did not consistently dose him, sometimes missing 1-3 months in a row.  I also feel as he is getting older that it’s possible his system is changing. We have had our other dogs over the past 20 years on Heartgard with no adverse effects although our last two dogs had cancer so who knows.

Due to this experience with Carson & a lot of research on our part, we are reconsidering the recommendations from vets of monthly dosing especially since we are in a relatively low risk area for heartworm.

We scheduled an appointment with a holistic vet on the following Wednesday after the Heartgard dosing.  Since Carson was now getting his liquids through chicken broth that we made, we asked the vet to do a drip infusion of water as well as a blood draw.  His blood tests came back normal.

Thursday evening (the week following the dosing) was Carson’s worse night.  We thought we would have to put him to sleep the next day. He was not able to walk up/down the stairs on his own; we had to use a sling to help him & he was in a lot of discomfort with his symptoms.

During the night we had done more online research & came across a lipid infusion treatment which essentially helps to flush out the Ivermectin which is fat soluble.  After calling several vet specialists, we were able to find a practice who had this product in stock.

The vet argued with us saying we should be doing neurological testing.  He told us the lipid infusion would be a waste of time & money. Our take was since the infusion would not hurt Carson let’s start there & we could always do more testing if it didn’t make a difference.

The vet relented & did the infusion on 9/28/18.  When we picked up Carson 4 hours later he was already more mobile & alert!!  With each passing day he has shown signs of getting more back to normal.

We were cautiously optimistic that Carson would get through this.  In spite of Carson being a super high maintenance dog he is our family & it was killing us to see him in such discomfort.  Second side note: he also has exertional rhabdomylosis in his older age which we self diagnosed after the vet’s blood work showed nothing abnormal & doing some google research.

At day 10 since the lipid infusion,  Carson was able to jump on the bed, get up & down the stairs on his own sometimes with a bit of coaxing, was able to go on short walks, was sleeping less & more alert, had more energy, was playing with toys & yes humping his blanket, gross but heartwarming at the same time considering where he was at two weeks prior.  He is almost back to normal with the exception that his hind legs are not 100% coordinated & his right leg in particular drags.

We also started him on CBD oil within 2 days of the Heartgard dosing since it’s supposed to help with seizures & a host of other issues.  He’s also been on Red Gold, an anti-inflammatory which we found at SF Raw, a store in San Francisco focused on raw pet foods & supplements.

We are also transitioning Carson off the phenobarbital to Keppra, an anti-seizure medication which is supposed to be safer long term which we learned about through our holistic vet.

Needless to say, after this horrible experience we will no longer be dosing our dogs with heartworm treatment especially since the number of cases in our area is fairly low.  Instead we will do blood tests 1-2 times a year.

Please check with your vets on best approach for your pet/s.  I highly recommend doing your own research as well. I think the drug industry really pushes for drug treatment when it may not be warranted & this is how many vets are trained/influenced in their prescription methods.

If you have personal experience with this or any other tips on keeping your pet healthy please share.

There are links below to several other resources.

MDR1 testing ($60).  Test can be ordered here:

Detailed article on MDR1 testing:

SF Raw site, organic, raw pet foods & supplements:

Detailed article on a vet who now practices from a holistic approach who does not recommend heartworm treatment:

The Heartworm Society with details about the lifecycle of heartworms:

Heartworm DNA test by Healthgene which is more accurate then other tests:

Facebook CBD oil for pets page:

Lazarus Naturals: CBD oil for dogs which I found through the Facebook group.  It’s really important to purchase CBD oil which is organic & tested since there are some poor quality products out there.

Dogs Naturally site: offers health information & natural supplements.  Sign up for their newsletters & download their heartworm guide:

Holistic vet in the East Bay with an informative website & alternative therapies including ultrasound & oxygen therapies.  There is also a link to petition legalizing medical cannabis for pets in California:

The Cannabis Pet:

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