Do I always need to seek the guidance of a veterinarian when giving my cat medicine?

I think that it’s a fabulous idea, and there's an excellent reason for that. Many of these cats can have multiple things going on, and they are very good at masking their signs until they're super sick. It's going to be vital that we get a good head-to-toe exam on these guys to get a feel for what's going on with them. Then we can identify any pain or disease to properly set up a medication if needed and get those things in order.

For most medications, I would say yes. Even if you are using something common like flea treatment, you want to make sure it's labeled for the cat. When cats are given an inappropriate medication or a dog medication, they can react severely to that.

Yes, cats are extremely sensitive creatures with more sensitivities to medications than humans. Veterinarians are professionals who can recommend and prescribe the appropriate therapy for your cat due to their understanding of cats' sensitivity to drugs.