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My 16lb dog accidentally ate a 500mg cephalexin pill. Is she okay?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed Small (up to 22lb) | Female | spayed | 3 years and 1 month old | 18 lbs

My other dog Is on cephalexin 500mg for a ear/skin allergy/infection. But KC (16lbs) accidently got the cheese wrapped pill and ate it even though I tried to make her spit it out. Is she going to be okay??

3 Answers

Most Helpful Answer

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Answered By Daniel Fonza, DVM

Veterinarian

Published on November 29th, 2017

Hi there and thank you for using Pet Coach to address your concern. At the high end of the dose of 60mg/kg for systemic infections, it would be approximately 436mg every 8 hours for that dose for a 16lb dog. A 500mg capsule will not likely cause any life threatening problems. You may see vomiting and diarrhea but this should resolve on its own. If you start to see neurological symptoms such as seizures or a wobbly gait, I would have a veterinarian examine KC. I hope this helps! Please let me know if you have any other questions or concerns and I would be happy to help further.

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    Answered By Jennifer Summerfield, DVM CPDT-KA

    Veterinarian, Certified Dog Trainer

    Published on September 23rd, 2019

    Hi there. Cephalexin is an antibiotic with a very wide margin of safety in dogs, so it's unlikely that this will cause any significant problems. She may have a minor upset stomach today (vomiting or diarrhea), but otherwise should be just fine. But to be safe, I would recommend calling your regular veterinarian to let them know what happened. They may want you to skip her usual evening dose today, or may have you start some medication to help with stomach issues if she develops any problems.

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    Answered By Linda G, MS, DVM

    Veterinarian

    Published on April 7th, 2018

    Hello. Cephalexin is a very common antibiotic used in pets & usually does not cause a problem, but your dog may indeed have a sensitivity to it. I am glad you held off giving the medication this evening, but I would try it again tomorrow morning about 30 minutes after she eats. If she holds it down, great but if she vomits then your veterinarian will need to prescribe another antibiotic on Monday if necessary. Continue the steroid as this is the more important medication. Thanks for using Petco Pet Education Center, formerly Petcoach.

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Hello. Cephalexin is a very common antibiotic used in pets & usually does not cause a problem, but your dog may indeed have a sensitivity to it. I am glad you held off giving the medication this evening, but I would try it again tomorrow morning about 30 minutes after she eats. If she holds it down, great but if she vomits then your veterinarian will need to prescribe another antibiotic on Monday if necessary. Continue the steroid as this is the more important medication. Thanks for using Boop by Petco.
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