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Why is my dog vomiting and having diarrhea after new meds and food?

Updated On September 23rd, 2025

Pet's info: Dog | Lhasa Apso | Male | neutered | 14 years and 5 months old | 12.1 lbs

My dog takes Prozac and transitioned from Clonidine to Trazadone last Wed. (w/ dose decrease on Thurs.),. He was fine until last night when he had diarrhea and threw up ~ 3.5h after meds (note, I put meds in eggs & cheese, which he ate fast & hasn't had in a while). Appetite seems unaffected & energy is consistent w/his regular laziness. Traz not doing much for his issues but no really notable side effects since lower dose on Thurs., but could this be delayed serotonin syndrome?

1 Answer

Most Helpful Answer

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Answered By Britni Miller, DVM

Veterinarian

Published on June 12th, 2017

My first thought when you said he vomited and had diarrhea was that Finn has an upset stomach from the eggs and cheese. If his energy level and appetite are normal, that would be my primary concern. If it continues or anything changes he should be seen by his veterinarian. Some behavior modification medications take some time (up to weeks) to take full effect. I would discuss this with your veterinarian if Finn shows no improvement.

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