Help with medication

A very sweet autistic boy, has grown into a 21 yr man who bites, kicks and punches his family.

He never hit, even as a baby. Never yelled, was gentle and reasonable. So much so, that a women I worked with who had an autistic daughter came to work bruised, I was sure it was her husband. I couldn't believe it.

When he turned 17, he started freezing up. For no reason, he'd just stop. He also seemed very sad, and seemed to develop an interest in girls that was heartbreaking. We took him to a doctor, who gave him paxil. He started gaining a little weight and became slightly aggresive (aggressive). We took him to a university hospital, they gave him an MRI to make sure he wasn't having seizures. He wasn't, they told us it was normal and take him to a therapist. We did, he gave us Risperdal. Within a couple of weeks, his tummy expanded. Within a couple of months, he went from a 34 inch waist, to  42. They took him off that, and switched to Geodon. Some of the freezing stopped, but he started to hit and bite. He started to become almost, and I'm sorry to use this word but insane. I don't know how else to describe it, he started saying things that even with his limited speech was scary. He started demanding things, crying, jumping up and down. Hitting his chest, and ulimately attacking us. He never did those things in school, it was limited to family.

He was taken off the Geodon, because it appeared to be the problem. We noticed, pretty quickly that he wasn't being as violent (6 months without a problem), started losing some weight. But the freezing started again, and recently he went back to biting. He tells us he is going to be the wolf in Beauty and the Beast and bite like they bit, the beast.After he draws blood, he calms down and tells us he's sorry.

We are at a loss. The doctors don't seem to know what to do. Does anyone here have any medication suggestions. I think he's handling the sexual urges for his age badly, he doesn't understand. He seems physically full of pent up energy.

Any help would be appreciated. We are scared for him and ourselves. This morning, he bit me 4 times. Al the while yelling, that I shouldn't have told him he can't have a toy (this is from a conversation we had years ago) with each bite, he said I'm wolf, I'm a Great Dane,