My kitten has flu. Can I use her prescribed meds for my other kitten?

Unfortunately no, that's not safe to do. Each kitten has to evaluated to be certain that a specific medication is safe for it. You will need to take your new kitten into the vet to get treated. Best of luck.

It looks like it is unknown if chlorpheniramine is excreted in milk - some antihistamines are while others aren't. All antihistamines may have the potential to decrease milk production so for this reason if the kittens are young it may be best to avoid the medication. If Kiko truly needs the medication you could discuss pros and cons of continuing with your vet - the benefits may outweigh the risks in her situation.

I would not use another cat's prescription as it may not be the same condition for your kitten. It is best to have the eye examined by your vet so they can rule out any issues such as injury to the eye, infections, etc that may require different treatments.

The majority of pet medicines are also used in humans. I am sure your vet understands which ones are safe to use in Jack. I don't use these medicines in the US, so I can't comment on their individual safety. You should call your vet with these additional questions.

There is nothing OTC that you can safely give them. It is important to keep them eating and as stress free as possible. Time in a steamed bathroom can loosen chest congestion if necessary. A respiratory infection can be quite serious in such a young kitten. Keep the kitten separate from the others if possible. Ideally, they should be examined by your veterinarian and placed on antibiotics if indicated.

Cat Flu is a general term that refers to an upper respiratory infection. In kittens, the biggest causes are usual one of a couple of different viruses that will go away with the infection. One of the viruses (herpes virus) will stay latent in the body and may come out again during times of stress. However, most cats have this virus already, so it's not standard for us to recommend isolation for the rest of kittenhood based on a history of cat flu. I would double-check the reason for the recommendation. I suspect there was something else going on with that case. The kitten should not be contagious if there were no signs of infection when you got her. Outside cats pose a risk of transmitting FIV and FeLV, which both affect the immune system and can be quite severe in kittens. I'm assuming that's why they recommended her not to go outside. From what you've described, I don't think you have much to worry about. Shelters commonly adopt out kittens with a history of cat flu and it's rarely a problem. Again, I think it's worth talking to the Vet at the SPCA. Sometimes the staff do not fully understand the situation and may have not explained this well enough. I hope that helps and you enjoy the new kitten. It's always great to see people adopting, so good on you.

Cat flu is very common in young cats and is very contagious to other cats as well. It is treated with antibiotic eye drops/ointment and oral antibiotics for about 2 weeks. if left untreated many cats will end up blind or even die from the disease. I advise going to your vet asap to start the treatment right away.