Vomiting cat - question about digestion

Our cat has been vomiting up everything since early this morning. He has a history of these bouts every 4-6 months or so. We give him metronidazole and the it resolves.

Today, the vet did an x-ray and ran blood work and except for lots of gas, everything looked normal. He got an injection of pepcid and some IV fluids and we were told to feed him a little of the prescription canned food and to call them if he can't keep that down. One good sign is that his appetite is 100% unaffected. I let him get a few good bites of the food, but didn't want to shock his system. But he ate it without any coersion.

Long story to get to my question...how long until I can know for sure that he's kept it down? How long does kitty digestion take? He ate about a quarter of the can maybe 3 hours ago. Are we in the clear yet??

Thanks for any insight.

What a frustrating problem for you.
Cat digestion is probably not that different from humans. I'd say 3 hours is plenty of time.

Thank you for your response. It is frustrating and anxiety is getting the better of me. He did hold down the wet science diet both last night and this morning. But I figured, 'let me give him a little treat before I go out" and gave him about a tablespoon full of dry sensitive stomach..I think it was purina one. When I got home from being out this afternoon, there was a little bit of the dry food puked up on the carpet. It looked barely digested. So I just gave him a little more wet now. He ate a little bit of it. I'll see if he holds this down.