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Updated on September 23, 2025
Pet's info: Cat | Domestic Shorthair | Female | spayed | 10 years old | 13 lbs
My cat was diagnosed with a UTI yesterday afternoon. She was prescribed Clavacillin (62.5 mg) and Onsior (6 mg). About 6.5-7 hours after her medicine she started throwing a foamy, yellow liquid and then all of her dinner. During the night, I woke up twice to her throwing up a foamy liquid with a slight color to it. I know the vet said the Clavacillin could upset her stomach but is this normal? Does she need to be brought to the ER or can she wait until her primary opens in a few hours?
2 Answers

Answered By Jessica Desrosiers
Veterinary Technician
Published on March 30, 2021
Answered By Dr. Massimo Orioles, DVM, Cert AVP, MRCVS
Veterinarian
Published on November 6, 2018
Usually not and these signs could be actually related to a gastrointestinal infection/inflammation.
It is indeed possible that the UTI is due to stress secondary to the gastrointestinal problem, which is the primary problem to be solved or it may be that the antibiotics are upsetting her stomach.
Another check up is indeed required if the sign do not resolve with few days of a bland diet based on boiled chicken or white fish and rice in small portions given 3 or 4 times daily for a week.
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