Zorbium - Side Effects?! PLZ HELP!

Zorbium? Side effects?! Help!!

Had my cat neutered yesterday morning, and my vet gave him Zorbium, after the surgery was “totally successful”. Now my poor little dude- is TRIPPING so hard!!

He hasn’t slept in a day, at time’s lethargic, other time’s extremely zoomie; but my biggest concern is that he hasn’t used the liter box yet and it’s been a DAY! He is normally very hydrated, and well fed, but isn’t having it today.

Is there anything to do to help him pee? Make him more comfortable? Is this really going to turn off in 4 days?

HELP!