Crazy siamese

I have a almost 3 year old siamese. She was always kinda crazy when she was younger but we thought that was her being a siamese cat. As she got older it got worse and we couldn't have anyone over the house. We thought that she was just unhappy, so we got another kitten. She absouletly hates him..We can't let him out of the spare room because she tries to attack him. We brought her to the Vet and the vet said that in her 12 years as a cat only vet our cat was the worst one she had ever seen. The vet put her on Clomicalm which did nothing.Talking to the vet some more she said that maybe the cat wasn't happy in our house or unhappy with us and recommended that we try to give her to someone else. We contacted a rescue that works with the vet and put her on an adoption list which was really hard for us to do. Finally about a week ago someone came and adopted her. 2 days later she was back and the guy was claiming she was trying to kill him. Chasing him around his house scratching and biting.
Looking ahead towards the future and hopefully having kids we don't se her fitting into that situation.We would be afraid that she would attack a little baby...

Sorry for the long post but just needed to vent and see if anyone has any opinions or can be of any help..
Thanks.

Has she been spayed? I think I'd have a more extensive medical evaluation. Maybe a blood workup. It is unusual that the cat is that vicious. If she's that bad, they won't adopt her out. You can't have a cat that attacks people.

If you can't find anything wrong with her (where did you get her originally?), then for everyone's protection you might have to consider putting her to sleep. Sometimes you have to make tough decisions and this may be one of them.

yes she's been spayed.All blood work was done before she was put on clomicalm. My girlfriend is a vet tech. The vet also thinks that the cat might be inbred or scitsofrenic sp? we got her from a breeder

Ask the vet about amitriptyline (Elavil) - it will calm her down, no question!