Petco Text Logo
Petco Pet Logo
  • Two Easy Ways to Start Earning Rewards!

    rewards header
    Become a member today!
    Members-only pricing and offers, personalized care notifications, Vital Care points back on every purchase and more!
    Petco Pay LogoBecome a credit card member today!

    Earn 2X Pals Rewards points at Petco
    when you use Petco Pay!

    APPLY NOW
    Learn More About Petco Pay Benefits

Can I give my cat leftover Onsior for a swollen eye from herpes?

Updated on September 23rd, 2025

Pet's info: Cat | American Shorthair | Male | neutered | 1 year and 11 months old | 10.13 lbs

Our feline friend Al has been having a tough time with feline herpes affecting his eye. He’s seen his regular vet and an ophthalmologist. Yesterday his eye got very swollen (can’t open) and purulent, as it always does when this flares up. He’ll be seeing his ophthalmologist this coming week but in the mean time, we have some left over Onsior from his regular vet which was given to treat his eye swelling, several months ago. Would it be ok to give him a dose today?

1 Answer

Most Helpful Answer

Laura Johnson VMD

Answered By Laura Johnson VMD

Veterinarian

Published on June 17th, 2018

Hi, thanks for using Petco Pet Education Center, formerly Petcoach! Poor Al!

I feel so bad for him based on your description. If the Onsior isn't expired and is the appropriate dosing for his current weight then you can give him a tablet. Do not give it if he isn't eating or is vomiting. Do not give extra and follow the specific instructions, once daily for no more than 3 days. Call your Vet Monday before giving anymore.

Good luck!
Vote Icon1Pet Parents found this answer helpful

Smart Picks for Smart Questions

Have A Vet Question?

Book an appointment with the pros – our expert vets are here to help.

Share

Styled arrow button