Hi there! My name is ***** ***** I'd be happy to answer your question about your kitty!
When an animal has irritation to the stomach, even something like water can cause further irritation and the vomiting can continue due to that irritation.
When we see an animal having a bout of vomiting, we usually do pull up both the food and the water for a couple of hours just to give their stomachs a chance to settle down. If after that time frame, you're not seeing any vomiting, you can reintroduce small amounts of water back to his diet, then slowly reintroduce small amounts of food.
Hopefully this should help to get him to feeling a little bit better and he'll stop vomiting. Ideally he should not start up again. Sometimes we may try to give them 1/4th of a 10 milligram plain pepcid AC/famotidine to help get the acid in their stomachs under control, and that can help with that icky tummy feeling.
However, given the age of your kitty, if the vomiting continues after you've given him a chance to settle, it's a good idea to get him into a vet to get checked out. Older kitties are prone to developing issues with their kidneys
and other organs, and often the first thing we see when they develop an issue like this is tummy upset.
A bug or mild stomach irritation that is manageable at home should stop after an hour or two with no food or water. Should the vomiting continue past that point, then we do start to get worried about secondary issues like dehydration as well as what's causing the vomiting to occur.
If over the next couple of hours, he starts to get worse, is vomiting profusely, he grows very lethargic, or is showing any decline, you will want to get him into a clinic to be checked out tonight.
If he is improving and the vomiting stops, you can probably keep him home over the weekend, but it would still be a good idea to get him checked out by a vet during regular office hours on Monday, just to be sure everything is okay.
If you have any further questions or concerns or need clarification on anything, please feel free to hit "reply" to get back with me.