I conducted quite a few interviews at my previous job and my solution for the whiteboard anxiety problem is to give a set of coding exercises/questions on a pie

I conducted quite a few interviews at my previous job and my solution for the whiteboard anxiety problem is to give a set of coding exercises/questions on a piece of paper to the candidate and give him/her as much time as necessary to answer these in private in a separate office. When the candidate is ready he/she announces it and we review the solutions together. It is not perfect, but I find it much less taxing than being asked to solve a technical problem in a white board in front of an interviewer.