One of mine freaks out pretty badly too whenh they go in the carrier. I get scratched pretty good most of the time, but it is not very often. However, it not as bad as yours, once she is in the carrier everthing calms down.

Craftlady is right, before I would give seditives I would try to get yours used to the carrier. Sedating a cat is always a risky, and should only be done as a last measure. I know it is needed sometimes though.