Found a splendid article on TMJ. They talk about some hidden causes of TMJ and generally give a splendid overview of symptoms, causes, etc… They also talk reasonably a bit about prescription meds for TMJ. I would stay away from this. Bascially, a doctor can prescribe pain pills for you, but who wants to be taking pain pills for the rest of their life? I recommend more hollistic TMJ exercises rather than pills.
That article is here http://www.healthstatus.com/health_blog/2009/05/07/are-you-suffering-from-tmj/