http://www.provet.co.uk/health/diseases/paracetamol.htmparacetamol is dangerous to all living things, in particular cats, it can cause irreversible liver damage.
If your animal is in pain and you do not wish to use an NSAID such as Rimadyl (which I will not use) then have arnica in the house.
It is the best thing for pain and bruising and trauma. It can be used by humans and animals alike; is not toxic and I give it to my dogs prior to any surgey and post surgery (200c or 30c) and then also for every day bashes etc (6c).
It is easy to administer and arnica cream is also good for bruises (do not use on broken skin).