IS <BR> the only tag that is your concern?
If yes, instead of string HTML in your databse, just store it as plain text. From a textarea box, a line break will store in the database as chr(13).
When you pull it back out to display, apply the nl2br() function to your string.
But if there are other tags, then maybe you want to look for one of those JavaScript Formatting Bars like on this forum...