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Updated on September 23rd, 2025
Pet's info: Dog | Australian Shepherd - miniature | Male | neutered | 1 year and 2 months old | 24.7 lbs
I have a 14-month-old mini Australian Shepherd who tested clear on the MDR1 gene mutation, no known health issues. He’s taken Trifexis for 11 months for flea/heartworm prevention, Simparica added 3 months ago for tick prevention. Meds are given with meals 1-2 wks apart. We live in an area where heartworm & ticks are a problem so I need year-round preventives. Are there any known contraindications with this combo, or other meds that provide good protection with minimal side effects?
2 Answers

Answered By Juliana, DVM
Veterinarian
Published on February 24th, 2018
Answered By Laura Johnson VMD
Veterinarian
Published on December 23rd, 2019
Hi, thanks for using Petco Pet Education Center, formerly Petcoach!
Gump should be fine as long as each drug was correct for his weight. Simparica is only for fleas and ticks. Trifexis is for heartworm prevention, intestinal parasites and fleas. It doesn't cover ticks. It is common to use TWO drugs to prevent fleas, ticks, intestinal parasites and heartworm and there is not a single product that gets everything.
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