Because Australian Shepherds can carry MDR1 drug sensitivity, it’s really important to be careful about the flea and tick medications you choose. For some dogs, using the wrong product can have very serious consequences. If you’d like to learn more about MDR1, I have more information available on my website.
Some commonly used flea and tick products—like Bravecto, NexGard, Simparica, Simparica Trio, Credelio, and Revolution Plus—contain Isoxazoline, which works by affecting the nervous system of fleas and ticks.
While these medications are designed to target parasites, many pet owners have reported side effects in their dogs and cats. Every dog is different, but this is something to be aware of —especially with drug-sensitive Aussies.
Some of the reactions people have shared with me include:
Changes in personality or behavior
Aggression
Seizures
Disorientation or confusion
Wobbling or trouble walking
Sensitivity to touch
Unusual vocalizations
Loss of bladder or bowel control
In some cases - death
These reactions don’t always happen right away. Sometimes they can show up days, weeks, or even later after repeated doses.
Because of this, I personally recommend avoiding oral flea and tick medications when possible. Once a pill is given, it can’t be taken back. With topical products, if your dog has a reaction, you may be able to wash it off right away if you notice irritation like redness or a rash.
If you’re unsure, testing your dog for the MDR1 mutation can be a really helpful step in making safer choices. your breeder can likely tell you if your dog carries a copy or two of MDR1.
I also suggest letting your vet know that your dog may carry MDR1 (even if they haven’t been tested), just so they can take extra care when recommending medications. There are safer alternatives available for these drug.
For flea and tick prevention, I recommend Advantage II or Revolution. Advantage II is easy to find at most pet stores or online.
Here is my detox protocol:
https://drjudymorgan.com/blogs/blog/side-effects-from-common-flea-and-tick-products?_pos=2&_sid=4f37b2d66&_ss=r
Safer prevention options: https://drjudymorgan.com/collections/tick-and-flea
Flea and Tick Prevention Article: https://drjudymorgan.com/blogs/blog/flea-and-tick-prevention-revisited?_pos=7&_sid=56a77806b&_ss=r
