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My dog ate Zofran (Ondansetron). Is this dangerous? Should I go to ER?

Updated on September 23rd, 2025

Pet's info: Dog | Yorkshire Terrier | Male | neutered | 7 years and 11 months old | 8.3 lbs

My 7.5lb dog just ate/swallow 1 1/5 pills of dissolvable ondasteron (zofran) which equals to about 6mg. It was for my other dog and he ran up and snatched it in a treat. He already had 1/2 a pill (=2mg) 6 hours ago. Is this dangerous/should we bring him to the ER? Or will he be okay??? I’m worried

1 Answer

Most Helpful Answer

Andrea M. Brodie, DVM

Answered By Andrea M. Brodie, DVM

Veterinarian

Published on April 23rd, 2018

Ondansetron (Zofran) can cause constipation and atrial fibrillation even at normal doses. A normal dose would be 0.5mg to 1mg/kg twice daily, so your dog clearly got an overdose. This may be detrimental, but possibly also not.
You should take Cash to a Pet ER for inducing emesis (vomiting) or you can also call the pet poison line for advice:

24/7 Animal Poison Control Center

855-764-7661

$59 USD per incident fee applies
Vote Icon5Pet Parents found this answer helpful

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