Metacam?!

Just stumbled across a thread in here saying Metacam can kill cats... so went to look at what the vet prescribed my 600g (1.3lb) Delilah today for the pain she suffers when her eyes swell, and yup its Metacam.
What do I do???

I would voice your concerns to your vet. I used to take a blanket no meta cam stance but I have softened a little used with caution for some conditions it can be beneficial

Metacam is a non-steroidal anti-inflammatory drug, like aspirin, and those are well tolerated by dogs and people but not cats.  If the purpose is just to kill pain, there are better and safer painkillers available, such as buprenex (either placed on their gums if you are giving it at home, or injected by the vet) or tramadol, which can be compounded into a gel and applied to the naked skin inside the ear. Both control pain better than metacam.   Metacam can be extremely useful in bringing down a high fever, but it can be tough on the kidneys and according to one of my vets, if using metacam on a cat, you should always give fluids at the same time.  Also, metacam should be dosed once only.  If your vet chose metacam because of its anti-inflammatory action, he could use steroids instead to bring down inflammation and swelling.  Steroids are tolerated by cats a lot better than by dogs and people.  If your vet is a general practitioner, he might not be aware of how sensitive cats can be to NSAIDs.  If there is a feline specialist in the practice, or a cats-only clinic in your area, I would suggest getting a second opinion and seeing if there might be a better and safer alternative for your cat.

Also, you did not explain why her eyes swell and what's going on with that, because if we get to the cause of the swelling and eliminate it, then she won't be needing pain medication.