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Updated on September 23rd, 2025
Pet's info: Dog | Mixed Breed Medium (23 - 60lb) | Female | spayed | 2 years and 11 months old | 55 lbs
My dog (55lb) shepherd mix hasnt eaten and all of a sudden has terrible breath. Noticed after I gave her chewable flea&tick and heartworm meds 2 days ago. No change in medicine so not sure why that would cause an issue. Temperament and personality seems fine. 3 years old. Has been licking a lot as well.
2 Answers

Answered By Ana M, DVM
Veterinarian
Published on October 12th, 2018
Answered By Linda G, MS, DVM
Veterinarian
Hello. Licking & loss of appetite are classic signs of nausea, but what may be causing the nausea is a more difficult issue. It may be the medications you gave 2 days ago. Depending on the products, the new recommendations are to separate giving oral flea & tick from oral heartworm meds by 2 weeks. They should never be given together due to the potentiation of side effects. If Lyla does not want to eat by tomorrow, or develops any vomiting or diarrhea, please see your veterinarian as soon as possible. Thanks for using Petco Pet Education Center, formerly Petcoach.
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