How do you deal with a Narcissistic friend?

A friend of mine keeps making sly remarks with the intention of putting other downs.. often in a backhanded and subtle manner.. Recently, some of us friends went on a trip without inviting her. She made a big deal out of it and started sending hateful texts to the group that went out. I feel this has been like a final breaking point in our friendship..
Problem is she is an old friend. Do I completely cut her off? Anybody has dealt with similar people?