An interesting article published at The Sydney Morning Herald explores the use of beta blockers among musicians as a way to control performance anxiety. Professor Dianna Kenny, of Sydney University, surveyed 357 musicians for top Australian orchestras and found that 106 of them use beta blockers as a way to get through every concert in which they perform. Professor Kenny says that performance anxiety is more acute in musicians than in other performers, and has written a book entitled The Psychology of Music Performance Anxiety.
Whether you use beta blockers, psychotherapy, or other methods, it's important to remember that performance anxiety and social phobia can be overcome. Streisand, for example, returned to live performances in 1994, embarking on a successful comeback tour after nearly 3 decades of avoiding such situations.