What Dosage Of Buspirone Is Recommended For Anxiety?

My wife just started Buspirone as an antianxiety medication. Starting with a 5mg dosage, 3 times daily with titration to an eventual dosage of 20mg three times daily. I don't think this is going to work. The 5mg dose this morning at 0700 made her very very anxious. She tried the second 5mg dose at 1300 and has been unable to lie, sit or stay still. We just went for a walk and her walk is like she has weak knees. I know we will not take the third dose. I was looking for the half life or at what point this 10mg will somewhat metabolize or be almost out of her system? She is also on 40mg Prosac which I think may be interacting.